Update on non-O157 Shiga toxin-producing E. coli as a foodborne pathogen: analysis and control*

1 Update on non-O157 Shiga toxinproducing E. coli as a foodborne pathogen: analysis and control J. L. Smith, P. M. Fratamico and N. R. Launchi, United States Department of Agriculture, USA DOI: 10.1533/9781782421153.1.3 Abstract: Although Shiga toxin-producing Escherichia coli (STEC) O157:H7 is a leading cause of foodborne illness worldwide, non-O157 STEC serogroups may cause more illnesses than O157:H7, and information on transmission and outbreaks is presented. The role of ruminants as a major reservoir for both O157 and non-O157 STEC is explored, and how ingestion of contaminated animal products or produce contaminated by animal feces can lead to illness is discussed. Intervention strategies that control STEC O157:H7 and also inactivate non-O157 STEC are identified. Methods for detection of highly virulent non-O157 STEC are described and the need for additional research to understand the prevalence, epidemiology, and virulence of these pathogens is emphasized for their effective control. Key words: non-O157 Shiga toxin-producing Escherichia coli, foodborne pathogens, Shiga toxin, virulence genes, animal reservoirs.

1.1

Introduction

Shiga toxin-producing Escherichia coli (STEC) are diarrheic foodborne pathogens that are the major causative agents of hemorrhagic colitis (HC) and postdiarrheal hemolytic uremic syndrome (HUS) leading to severe kidney disease and even death. E. coli O157:H7 has, for many years, been Notice: This manuscript has been authored by J. L. Smith, P. M. Fratamico and N. R. Launchi with the Agricultural Research Service, United States Department of Agriculture. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes.

Published by Woodhead Publishing Limited, 2015

4

Advances in microbial food safety

the major STEC strain causing HUS. Use of improved methods for the detection and identification of non-O157 STEC have revealed that the number of non-O157 STEC infections is overtaking O157:H7 as the main cause of STEC-associated illness (Gould et al., 2013; Scallan et al., 2011). In general, the non-O157 STEC do not cause as severe disease as the O157 STEC but some non-O157 STEC strains have caused HUS (Gould et al., 2013). The intestinal tracts of animals used as a food source, particularly cattle and other ruminants, are reservoirs of both O157 and non-O157 STEC; therefore, during slaughtering operations, the carcass may become contaminated, leading to meat products containing the pathogens. Surveys of cattle (feces, hides, and pre- and post-intervention carcasses) showed similar levels of E. coli O157:H7 and non-O157 STEC. Produce and vegetables may be contaminated with STEC strains because fecal excretion by animals can contaminate soil and water sources (Kaspar et al., 2010). Other animal reservoirs for STEC include goats, sheep, guanaco, deer, and elk. There was an outbreak associated with deer meat contaminated with STEC O103:H2 in high school students in Minnesota in 2010 (Rounds et al., 2012). Non-ruminants, including cats, dogs, pigs, horses, rabbits, and poultry, as well as transport hosts, including birds, rodents, flies, and beetles can also carry STEC. An awareness of the importance of the non-O157 STEC as foodborne pathogens is critical for food microbiologists, food processors, food regulators, and clinicians; however, there is, overall, less known about this heterogeneous group of pathogens than about STEC O157:H7. This chapter provides information on transmission and outbreaks caused by non-O157 STEC, virulence factors, reservoirs, ecology, control strategies, and detection.

1.2 Virulence of non-O157 Shiga toxin-producing E. coli (STEC) 1.2.1

Non-O157 STEC serogroups and serotypes associated with human disease Based on data from US FoodNet sites for the period of 2000 to 2010, Gould et al. (2013) found that the non-O157 STEC serogroups caused a total of 2006 infections, and serogroup O157 was responsible for 5688 infections. Over 70% of the total non-O157 infections were caused by serogroup O26, O45, O103, O111, O121, and O145. Overall, 7.5% of non-O157 STEC infections were linked to outbreaks, whereas 19.5% of O157 STEC infections were outbreak-associated. Infections caused by non-O157 STEC were more commonly associated with international travel (16.2%) than O157 (2.7%). In addition to the six non-O157 serogroups listed above, Gould et al. (2013) list 66 other non-O157 serogroups responsible for illness in the United

Non-O157 Shiga toxin-producing E. coli as a foodborne pathogen

5

States. For the period 2007 to 2010, the European Union (EU) reported 2140 cases of STEC-induced illness. STEC O157:H7/H− was responsible for 1047/2140 (49.0%) cases, and 1093/2140 (51%) cases were attributable to non-O157 STEC (EFSA, 2013). Serogroups O26, O63, O91, O103, O111, O117, O121, O128, O145, and O146 accounted for 48.5% (530/1093) of non-O157 STEC cases in the EU. Non-O157 STEC serotypes associated with confirmed HUS cases in the EU during 2007 to 2010 include: O1:H42, O7:H6, O26:H11, O76:H19, O80:H2, O86:H27, O91:H10, O104:H21, O105:H18, O111:H−/H8, O121:H19/H2 , O123:H2, O128:H2, O145:H−/H28, and O174:H2/H21 (EFSA, 2013 [their table 13]). Although there are some STEC serotypes such as O26:H11, O111:H−, O121:H19, and O145:H− that are important causes of serious illness both in the USA and in Europe, there are other serotypes that are more common in Europe than in the USA and vice versa. 1.2.2 Diseases caused by non-O157 STEC In general, non-O157 STEC infections are not as severe as O157 infections. The median hospital stay is 3 days with both types of STEC infections; however, during the period of 2000 to 2010 in the USA, only 13.7% of patients infected with non-O157 STEC were hospitalized compared with 43.4% for O157 cases (Gould et al., 2013). During that period, 33 deaths were reported for O157 STEC but only two were due to non-O157 STEC. Data from cases reported in 2008 to 2009 indicated that diarrhea was common with both types of STEC but 85.5% of O157 STEC cases presented with bloody diarrhea compared with 54.8% of non-O157 STEC cases. Only 1.3% (4/301) of non-O157 cases developed HUS whereas 10.7% (83/773) of O157 cases contracted HUS. The four cases of HUS associated with non-O157 infection were attributable to serogroups O111 (two cases) and one case each by O103 and O121 (Gould et al., 2013). In 2012, STEC O157 accounted for 531 foodborne infections whereas non-O157 accounted for 551 infections. Reports indicated that O157 and non-O157 STEC caused 187 and 88 hospitalizations, respectively (CDC, 2013). Long-term consequences may occur in some patients with diarrhea-associated HUS. HUS occurs more often in children and the elderly, and it is the most common cause of acute renal failure in children. Shiga toxin causes glomerular damage with development of anemia, thrombocytopenia, and renal failure. Extrarenal lesions may involve the gastrointestinal tract, pancreas, liver, cardiovascular system, and central nervous system (Gallo and Gianantonio, 1995). Extrarenal lesions are rarer today because of early intervention by dialysis of the affected patient. 1.2.3 Non-O157 STEC virulence genes Some genes that may be necessary for virulence in O157:H7 and non-O157 STEC are presented in Table 1.1. The production of Shiga toxin (Stx) by

6

Advances in microbial food safety

Table 1.1 Virulence genes present in O157 and non-O157 STEC. Values are number of isolates positive by PCR with percentages given in parentheses O157:H7/H− (n = 52, and 14 associated with HUS)

Non-O157 STEC, associated with HUS (n = 19)

Non-O157 STEC, not associated with HUS (n = 194)

Shiga toxins 18 (34.6) stx1 52 (100) stx2

5 (26.3) 17 (89.5)

137 (70.6) 81 (41.7)

LEE genes 52 (100) eae

17 (89.5)

118 (60.8)

Plasmid-associated genes 51 (98.1) ehxA 0 (0.0) saa 0 (0.0) subA 48 (92.3) espP 48 (92.3) katP 51 (98.1) etpD

18 1 1 13 7 3

(94.7) (5.3) (5.3) (68.0) (37.0) (15.8)

133 12 7 76 44 22

(68.6) (6.2) (3.6) (39) (23.0) (11.3)

O-island 122 52 (100) pagC 52 (100) sen 52 (100) nleB 52 (100) nleE 52 (100) efa1 52 (100) efa2

8 17 17 17 17 17

(42.1) (89.5) (89.5) (89.5) (89.5) (89.5)

49 94 94 90 84 84

(25.2) (48.4) (48.4) (46.4) (43.3) (43.3)

Genes

Modified from Buvens and Piérard (2012).

STEC strains is the most critical virulence factor responsible for HC and HUS. There are two types of Stx: Stx1 and Stx2; and several variants of both are known. Stx2 is ca. 1000 times more toxic than Stx1 toward renal microvascular endothelial cells (Gyles, 2007). The toxins are encoded by genes carried on lysogenic phages located in the STEC chromosome. Both toxins have an A1B5 structure; the B moiety binds to globotriaosylceramide (Gb3) present on host microvascular endothelial cell surfaces (kidney, intestine, and brain) followed by endocytosis of the toxin (Ivarsson et al., 2012). The A subunit is released from the B moiety and enters the cytosol via chaperone-mediated transfer. The A subunit acts as a 28S RNA N-glycosidase, blocking protein synthesis and inducing apoptosis of endothelial cells, particularly those of the kidneys (Ivarsson et al., 2012; Khan and Naim, 2011). The renal glomerular endothelial cells swell and detach from the basement membrane, fibrin thrombi form, and there is narrowing of the capillary lumen leading to a reduced blood supply to the glomeruli causing a loss of kidney function (Gyles, 2007). Genes on the 35-kb chromosomal pathogenicity island, LEE (locus of enterocyte effacement), encode important STEC virulence factors. There are three distinct factors of LEE: the adhesin known as intimin and the

Non-O157 Shiga toxin-producing E. coli as a foodborne pathogen

7

translocatedintimin receptor (Tir), the type III protein secretion system (TTSS), and the secreted proteins EspA, EspB, and EspD (Khan and Naim, 2011). Intimin (encoded by eae) enables the STEC cell to attach to the intestinal epithelial cells and induce attaching and effacing (A/E) lesions. Tir (encoded by tir) passes through the host cell membrane via TTSS to form a transmembrane structure with one terminal located in the cytoplasm and the other terminal binding to intimin (Khan and Naim, 2011). Thus, the binding action of Tir produces an intimate attachment of the microorganisms to the host cell. The genes espADB encode the translocator proteins EspA, EspB, and EspD, which form the conduit through which the TTSS delivers effector proteins to the host cell. The LEE-encoded proteins induce efficient bacterial colonization, dissemination, and multiplication in the intestinal tract. In addition, these proteins induce A/E lesions with resultant microvillus destruction and actin reorganization to form a cup-like structure around the micro-organism attached to the enterocyte (pedestal formation). Pedestal formation allows STEC to remain extracellular while enabling the cells to avoid immune consequences (Lara-Ochoa et al., 2010). Individuals infected with STEC producing Stx2 have an increased risk of developing HUS and the presence of both the stx2 and eae genes is a strong predictor of HUS induction (Gyles, 2007). The data presented in Table 1.1 indicate that a higher percentage of non-O157 STEC strains associated with HUS were more likely to carry the stx2, ehxA, and eae genes, as well as some O-island 122 (OI-122)-associated genes than strains not associated with HUS. Additionally, other genes postulated to be associated with virulence are found on large plasmids present in STEC strains. For example, pO157, present in O157:H7 STEC carries the ehx operon responsible for synthesis and transport of enterohemolysin, katP, and espP genes encoding a biofunctional catalase peroxidase and serine protease, respectively, as well as the etpD gene, which is involved in type II secretion (Caprioli et al., 2005; Khan and Naim, 2011). The katP, espP, and ehx operon genes are present on the large plasmid present in LEE-positive O26:H11 and O145:NM STEC indicating that the plasmids from these STEC strains are closely related (Fratamico et al., 2011b; Yan et al., 2012). Non-O157 STEC lacking LEE (i.e., eae negative), also have similar large plasmids which carry genes such as ehxA and espP (Newton et al., 2009). In addition, LEE-negative nonO157 STEC strains may have plasmid-associated subAB and saa genes, which encode for the subtilasecytotoxin and autoagglutinating adhesion proteins, respectively (Irino et al., 2010; Paton et al., 2001). The saa and subAB genes appear to be limited to eae-negative STEC. The STEC strains have been divided into seropathotypes (SPT): STEC in SPT-A are HUS- and outbreak-associated (O157:H7); STEC in SPT-B are less commonly associated with outbreaks but can cause severe disease (O26:H11, O103:H2, O111:H8/NM, O121:H19, O145:NM), SPT-C can cause severe illness, but rarely causes outbreaks (O91:H21, O104:H21, O113:H21, as well as other serotypes), SPT-D is diarrhea-associated and rarely

8

Advances in microbial food safety

outbreak-associated, and serotypes in SPT-E are not associated with illness. Multiple serotypes are found in SPT-D and SPT-E (Karmali et al., 2003; Mora et al., 2012). In addition to the LEE pathogenicity island (PAI), several other PAIs (n = 11) are found in seropathotypes A and B; PAIs are rarer in strains within seropathotypes C, D, and E (Imamovic et al., 2010). Important PAIs associated with HUS present in SPT-A, -B, and -C strains include OI-122 and OI-57. OI-122 was present in 19/34 (55.9%) of SPT-A and -B strains but in only 17.2% (11/64) of SPT-C,D,E strains. HUS was induced by 26/56 (46.4%) strains of SPT-A, -B, and -C strains containing OI-122 but in only 4/42 (9.5%) of SPT-D and -E strains (Ju et al., 2013). Genes present on OI-122 include pagC (encodes a virulence factor required for survival in macrophages), sen (encodes an enterotoxin), efa1/2 (encode adherence factors), and nleB/E (encode proteins that inhibit host cell inflammatory responses). OI-57 was present in 28/34 (82.3%) SPT-A and -B but in only 14 of 64 (21.9%) of SPT-C,D,E strains. HUS was induced by 60.7% (34/56) of SPT-A,B,C strains whereas only 19.0% (8/42) of SPT-D,E strains containing OI-57 induced HUS. OI-57 genes include nleG genes whose functions are unknown (Ju et al., 2013). The presence of OI-122 and OI-57 is strongly associated with the presence of LEE in STEC strains (Ju et al., 2012). The data presented in Table 1.1 suggest that a number of genes may be associated with severe illness (HC and HUS), but Gyles (2007) and Konczy et al. (2008) indicate that the eae and stx2 genes are the most important virulence genes.

1.2.4 Impact of diet on O157 and non-O157 STEC virulence Fermentation of dietary fiber in the colon results in the formation of shortchain fatty acids including butyrate. Butyrate leads to the increased expression of Gb3. Binding of Stx to Gb3 is an important part of the disease process induced by STEC (Zumbrun et al., 2013). Utilizing mice fed a high fiber diet, Zumbrun et al. (2013) found that this diet increased the intestinal colonization of E. coli O157:H7 86-24 and led to a 25% greater mortality than in mice fed a low fiber diet. They further demonstrated that binding of Stx to colonocytes and renal tissue of the mice fed a high fiber diet was greater than that of mice fed a low fiber diet. In addition, mice fed a high fiber diet had a reduced level of commensal E. coli that may promote enhanced colonization of STEC. The experiments in mice suggest that a high fiber diet with resultant increased binding of Stx may result in a higher incidence of severe disease induced by O157 and non-O157 STEC.

1.3 Animal reservoirs of non-O157 STEC Non-O157 STEC have been isolated from the feces of a variety of animals, both domestic and wild. However, ruminants, particularly beef and dairy

Non-O157 Shiga toxin-producing E. coli as a foodborne pathogen

9

cattle, are the most important reservoirs of both O157 and non-O157 STEC (Hussein and Bollinger, 2005; Hussein and Sakuma, 2005).

1.3.1 Cattle Surveying published studies from a number of countries (1989–2004), Hussein and Bollinger (2005) found that testing of beef cattle feces for O157 STEC showed a prevalence rate ranging from 0.2 to 27.8%, whereas the prevalence rate for non-O157 STEC was 2.1 to 70.1%. Hussein and Sakuma (2005) did a similar survey (1991–2004) to examine fecal shedding of STEC in dairy cattle. The prevalence rate for shedding O157 STEC was 0.2 to 48.8%, whereas the prevalence rate for non-O157 STEC serogroups was 0.4 to 74.0%. Jeon et al., (2006) obtained 809 fecal samples from beef and dairy cattle located on 209 farms in Korea and found that 54 fecal samples were positive for E. coli serogroup O26 (49 of these strains were positive for stx) and 77 samples contained serogroup O111 (28 strains were positive for stx). Pearce et al., (2006) determined the fecal shedding prevalence of E. coli serogroups O26, O103, O111, and O145 in Scottish beef cattle. They investigated 6086 fecal pats from 338 farms. Serogroup O26 was present in 279 fecal pats, serogroup O103 was present in 164, and serogroup O145 was present in 43 fecal pats. Serogroups O103 and O145 rarely carried the stx gene; however, 49.0% of the serogroup O26 isolates were positive for stx. The stx, eae, and ehxA genes were present in 28.9% of the O26 isolates (Pearce et al., 2006). In a survey of 20 Irish cattle farms (both dairy and beef), 107 of 1200 fecal samples and 600 soil samples contained STEC strains (Monaghan et al., 2011). The most common isolate was serotype O113:H4 (n = 31); other serotypes were O26:H11 (n = 14), O2:H27 (n = 13), and O168:H2 (n = 10) (Monaghan et al., 2011). Tanaro et al. (2012) studied the STEC prevalence in 292 fecal swabs obtained on an Argentinian beef farm between September 2005 and November 2006. The prevalence of STEC in the fecal samples was 37.7% (110/292). The STEC strains consisted of 24 serotypes and included O103:H2 (n = 12), O136:H12 (n = 8), O178:H19 (n = 8), and O103:NM (n = 5) (Tanaro et al., 2012). Fecal samples obtained from beef cattle in 21 feedlots from four US states were tested by PCR for seven STEC serogroups (Dargatz et al., 2013). All of the feedlots (100%) were positive for O157 and O45, 90.5% for O26, 85.7% for O103, 76.2% for O121, 33.3% for O145, and 19.1% were positive for O111. All of the feedlots were positive for one or more of the serogroups (Dargatz et al., 2013). In a study that compared the prevalence of non-O157 STEC in Spanish beef herds to dairy cattle herds, Oporto et al. (2008) found the prevalence in dairy herds was 20.7% (17/82), whereas the prevalence of non-O157 STEC was higher in beef cattle herds at 46.0% (57/124 herds). A total of 2540 isolates from dairy cattle feces, farm environments, and manure piles

10

Advances in microbial food safety

on eight organic and 20 conventional farms in the state of Minnesota were examined for the presence of STEC (Cho et al., 2006). The prevalence of Shiga toxin-encoding E. coli in organic dairy farms ranged from 0 to 26% (median 5.4%) and that for conventional farms ranged from 0 to 13.9% (median 1.1%). Forty-three STEC strains belonging to 19 different serogroups were isolated (Cho et al., 2006). Using rectal stool samples from 932 healthy dairy cows from 123 farms in Japan, Kobayashi et al. (2009) demonstrated the presence of the stx gene in 283 animals, and they isolated 118 STEC strains. Serogroup O157 was not isolated and about half of the strains belonged to serogroups O2 (n = 12), O8 (n = 18), O26 (n = 8), O117 (n = 6), and O153 (n = 14). The STEC isolates from five Argentinian dairy farms consisted of 156 strains belonging to 29 serogroups (Fernández et al., 2010). The major serotypes consisted of O130:H11 (n = 37), O178:H19 (n = 34), O113:H21 (n = 17), and O91:H21 (n = 15). Thus, a number of studies indicate that dairy and beef cattle carrying STEC normally excrete the organisms in their feces; most animals excrete ca. 102 cfu g–1. However, there are animals known as super-shedders of STEC, and Chase-Topping et al. (2008) have defined super-shedders of O157 as cattle that excrete >104 cfu g−1. As expected, cattle can also be super-shedders of non-O157 STEC. Menrath et al. (2010) studied the fecal shedding of non-O157 STEC in 133 dairy cows in Germany over a period of one year and found that 14 of these cows were super-shedders. Thus, super-shedding of STEC is not limited to O157 strains but also includes non-O157 strains. This study showed that super-shedders are an important cause of STEC shedding on cattle farms, and Menrath et al. suggested that removing super-shedders from farms would reduce the STEC burden. A review by Arthur et al. (2010) describes the impact of super-shedders on transmission of E. coli O157:H7 on cattle farms, on hide contamination, and on subsequent beef carcass contamination.

1.3.2 Other animals Ruminants such as sheep, goats, buffaloes, and cervids have been shown to excrete non-O157 STEC, but they may be minor sources of STEC-induced disease compared with cattle. Animals such as swine, rabbits, and companion animals harbor STEC but are not considered to be important sources leading to infection of humans. STEC are rarely found in horses and poultry (Kaspar et al. 2010). It has been shown that wild birds, rodents, and insects may carry STEC and may transport the pathogens to foods (Kaspar et al., 2010).

1.4

Outbreaks caused by non-O157 STEC

In Table 1.2, reports (1993–2013) of outbreaks caused by various serogroups or serotypes of non-O157 STEC are listed. A number of reports list only

35 (2 HUS)

19 states

USA, 11 states

Norway Colorado, USA Colorado, USA Maine, New York state, USA

O26 O111 O26:H11 O26

8 (2 HUS)

France

O26

29

Minnesota

USA, 9 states

3 (1 HUS)

19 8 45 3

29

18

52

26

New York state, USA New York state, USA Northern Ireland

O145

O111:H21 (stx2c+, aggR+) O103:H2 and stx¯ O145:NM O104:H4 (stx2a+, aggR+)

O45

O111

23 (4 HUS)

Germany

O104:H4 (stx2+, aggR+) O121

? (9 HUS)

Italy

O26

Cases

Location

Reported non-O157 STEC outbreaks

STEC strain

Table 1.2

Farms, animal contact ? Person-to-person Ground beef

Raw clover sprouts

Travelers to Turkey; not believed to be related to eating sprouts ?

Venison

?

Unpasteurized apple cider Ill food handler

Frozen food products

Infected food handler

?

Vehicle

(Continued)

www.cdc.gov/ecoli/2012/O145-06-12/index.html Accessed 16 February 2014 www.cdc.gov/ecoli/2012/O26-02-12/index.html Accessed 16 February 2014 Møller-Stray et al., 2012 CDC, 2012 Brown et al. 2012 See footnote a

Jourdan-da Silva et al., 2012

Rounds et al., 2012

Dallman et al., 2012

Schaffzin et al., 2012

www.cdc.gov/ecoli/2013/O121-03-13/index.html Accessed 16 February 2014 Schaffzin et al., 2012

www.promedmail.org/direct. php?id=20130815.1881558Accessed 16 February 2014 Diercke et al., 2013

Reference

33 12

Norway Oklahoma, USA

USA, five states

France

Denmark Norway Belgium

Japan Japan

O145

O123:H−

O26:H11 O103:H25 O145:H28 and O26:H11 O26:H11 O103:H2

O26:H11 O21:H19

O26 O26:H11, O80:H2 O148:H8 O45:NM

20 17 (10 HUS) 12 (5 HUS)

Europe

O104:H4 (stx2+, aggR+) O145:H28 O111:NM

10 (2 HUS) 52

France New York state, USA Ireland Japan 13 (1 HUS) 63

16 (16 HUS)

Japan France

2 (1 HUS)

31 (3 HUS)

86 (34 HUS, 21 encephalopathy, five deaths) >4000 (>900 HUS) 16 341 (25 HUS)

Japan

O111

Cases

Location

Continued

STEC strain

Table 1.2

? Contact with animals

Person-to-person Probable person-toperson ? Camembert made from raw milk Undercooked mutton Ill food worker

Sprouts from fenugreek seeds ? Restaurant-associated food Shredded romaine lettuce Undercooked ground beef Fermented beef sausage Cured mutton sausage Ice cream

Raw meat

Vehicle

Sayers et al., 2006 Akiba et al., 2005

Espié et al., 2006 CDC, 2006

Miyajima et al., 2007 INVS, 2007

Sonoda et al., 2008 Muraoka et al., 2007

Ethelberg et al., 2009 Schimmer et al., 2008 Buvens et al., 2011; De Schrijver et al., 2008

Wahl et al., 2011 Calderon et al., 2010; Piercefield et al., 2010; Bradley et al., 2012 www.cdc.gov/ecoli/2010/ecoli_O145/index.html Accessed 16 February 2014; Taylor et al., 2013 King et al., 2010

World Health Organization, 2011

Takanashi et al., 2014

Reference

4 58 (2 HUS) 32 (3 HUS) 10 126 (10 HUS) (21 HUS) 5 (1 HUS) 18 53 (23 HUS) (9 HUS) (6 HUS)

Ireland Texas, USA Japan Australia Ireland Japan France

Australia Ohio, USA Montana USA Australia Italy France

Mettwurst ? Pasteurized milk Fermented sausage ? ?

? Salad, ice Mixed vegetables ? ? Salad (probable) Person-to-person

? ? ? ? ? Unpasteurized cow’s milk ? Beef (probable) Swimming, ingestion lake water

Paton et al., 1996 Banatvala et al., 1996 CDC, 1995b CDC, 1995a Caprioli et al., 1994 Mariani-Kurkdjian et al., 1993

McMaster et al., 2001 CDC 2000; Brooks et al., 2004 Hiruta et al., 2000 Paton et al., 1999 Birchard, 1999 Hashimoto et al., 1999 Boudailliez et al., 1997; Morabito et al., 1998

Misselwitz et al., 2003 Werber et al., 2002 McCarthy et al., 2001

Kato et al., 2005 Kato et al., 2005 Kato et al., 2005 Kato et al., 2005 Kato et al., 2005 Allerberger et al., 2003

a

http://www.outbreakdatabase.com/details/cargill-meat-solutionsbjs-wholesale-club-ground-beef-2010/?organism=Non-O157+STEC Accessed 16 February 2014.

(3 HUS) 11 11 (3 HUS)

Germany Germany Connecticut, USA

O26:H11 O26:H11 O121; one isolate was O121:H19 O26:H11 O111:H8 O26:H11 O113:H21 O26 O118:H2 O111:H2 (Stx2 + EAgg) O111:H− O111:NM O104:H21 O111:NM O111:NM O103:H2

73 6 2 6 5 (2 HUS)

Japan Japan Japan Japan Japan Austria

O111:NM O26:H11 O146:H19 O169:H19 O103:H2 O26:H−

14

Advances in microbial food safety

the number of HUS cases, so it is not clear how many patients suffered diarrhea or HC. The vehicle was unknown in 19/53 outbreaks, but meat was identified as the vehicle in 10/53 outbreaks. Serogroup O26 was involved in 18/53 outbreaks, and serogroup O111 was associated with 11/53 of the outbreaks. Serogroups O45, O103, O121, and O145 accounted for 14/53 of the outbreaks. Thus, these six serogroups were responsible for 43/53 (81.1%) of the non-O157 STEC outbreaks reported from North America, Europe, Japan, and Australia.

1.5 Transmission of non-O157 STEC to humans The primary source of STEC leading to human infections is cattle feces (Karch et al., 2005). Therefore, contact with cattle, the cattle environment, or cattle products are major risk factors for sporadic and outbreak associated STEC infections. A Canadian study (Valcour et al., 2002) and a German study (Frank et al., 2008) demonstrated that there is a relationship between the density of cattle and risk for contracting a STEC infection. An increase in the ratio of cattle to humans and living in a rural environment were positively related to STEC infection. In the German study, the risk for STEC infection (both O157 and non-O157) increased by ca. 70% with an increase of 100 cattle/km2. Haus-Cheymol et al. (2006) investigated pediatric HUS cases occurring in France between 1996 and 2001 and found that HUS incidence was correlated with an increased density of dairy cattle. An increased ratio of calves to the population of children was significantly associated with pediatric HUS (Haus-Cheymol et al., 2006). Unlike other pathogenic E. coli (for example, enterotoxigenic E. coli), only a few STEC cells are needed to cause an infection. The estimated infectious dose of O157:H7 is quite low, in the range of less than 100 organisms (Karch et al., 2005). The infectious dose of STEC O26, O111, and O145 appears to be similar to that of O157 strains; however, the infectious dose for most non-O157 STEC is unknown (FSIS, 2012). Animal contact, particularly ruminants, is an important route of transmission of STEC infection to humans. Hale et al. (2012) estimated that 7.3% of the domestically acquired non-O157 STEC infections in the USA are the result of contact with animals on the farm, petting zoos, or pets. Facilities for thorough hand-washing, banning food consumption around animals, and educating individuals about microbial transmission by animals are important recommendations to ensure that animal contact does not lead to disease (Hale et al., 2012). The presence of STEC in ruminants and contamination of carcasses by feces during slaughter indicate that meats from ruminants, particularly beef cattle, are the major route by which STEC are transmitted to humans (Karch et al., 1999; Kaspar et al., 2010). Other food products such as milk and dairy products, and fruit and vegetables, as well

Non-O157 Shiga toxin-producing E. coli as a foodborne pathogen

15

as foods containing STEC as a result of cross-contamination can lead to infection (Kaspar et al., 2010; Mathusa et al., 2010). An important mode of STEC transmission in mental institutions, daycare centers, elderly care centers, schools, hospitals, and families is personto-person transmission. The infected index case sheds STEC and infects individuals in his/her immediate environment. Person-to-person transmission of STEC may be direct by physical contact or indirect through the use of materials handled by an infected person or through ingestion of food or water contaminated by an infected individual (Kaspar et al., 2010). Both recreational and drinking water have been implicated in several outbreaks of bloody diarrhea and HUS induced by O157:H7 STEC in the USA (Craun et al., 2005; Nwachuku and Gerba, 2008). However, waterborne outbreaks of non-O157 STEC are rarely reported. An outbreak that occurred in the state of Connecticut as a result of lake water contaminated with STEC O121:H19 involved 11 individuals (three had HUS) and was probably caused by swallowing water while swimming (McCarthy et al., 2001). A Japanese community water system contaminated by STEC O26:H11 was responsible for hemorrhagic diarrhea in a 2-year old girl but no other ill individuals were found (Hoshina et al., 2001). However, the feces of 11 nonsymptomatic individuals were positive for O26:H11. Water sources are probably an important means of non-O157 STEC transmission but are rarely reported.

1.6

Interventions for control of non-O157 STEC in produce

Information concerning the presence of non-O157 STEC in leafy greens, fruit, and vegetables appears to be limited. STEC O157:H7 has been associated with several outbreaks resulting from contaminated produce, especially leafy greens (Cooley et al., 2007; Jay et al., 2007; Slayton et al., 2013; Söderström et al., 2008). The data presented in Table 1.2 indicate that nonO157 STEC have also caused outbreaks in produce: O111 in apple cider, O26 in red clover sprouts, O104:H4 (stx2 and aggR positive) in fenugreek seed sprouts, O145 in shredded romaine lettuce, O111:H8 in salad, and O26:H11 in mixed vegetables. The outbreak data indicate that both O157:H7 and non-O157 STEC can be present in produce; however, the incidence of non-O157 STEC in produce has not been reported in systematic studies. Sources of produce contamination by STEC include run-off water from livestock areas (dairy farms or beef and swine-raising facilities) that drain into irrigation waters, use of animal manure as a fertilizer, and wild and domestic animal invasion of produce growing areas (Berger et al., 2010, Kase et al., 2012a). Land used for the growth of produce crops should not be in close proximity to animal-rearing facilities and the land should not be fertilized with animal manure unless it has been properly composted. Care must be taken that irrigation water not be contaminated with run-off water

16

Advances in microbial food safety

from dairy farms and animal-rearing facilities (EFSA, 2011). After harvesting, produce should be washed with potable water and the products handled in a hygienic manner. At the retail level, personnel must be trained to handle produce appropriately and the produce must be stored at proper temperatures (EFSA, 2011). The consumer must also practice good hand hygiene, must prevent cross contamination, and must store produce at the proper temperature. Leafy greens are a particular concern to consumers. Consumers should ensure that cut package leafy greens have been refrigerated at the store. They should be aware that cut, washed, and packaged leafy greens are not free of bacteria and may be contaminated (Kase et al., 2012b) and that the cut surfaces leak fluid, which is an excellent bacterial medium. Thus, such products have a limited shelf life.

1.7

Interventions for control of STEC in cattle

Many studies have been performed to determine the effect of cattle feeding regimens on shedding of STEC O157:H7 (Callaway et al., 2009; Jacob et al., 2009). Reducing or eliminating fecal carriage of STEC in cattle and other ruminants before the animals enter the food chain is important for decreasing human illness induced by STEC. Reductions of STEC shedding on the farm can reduce human exposure due to direct animal contact, as well as to STEC illness associated with water, fruit, and vegetables (Callaway et al., 2009; Jacob et al., 2009). Various types of cattle feedstuffs have been shown to reduce O157:H7 shedding; however, the results are inconsistent and often not reproducible. The inconsistent results of feeding studies suggest that the host–bacteria relationship is more complex than dietary influences alone (Jacob et al., 2009). So far, feeding studies in attempts to reduce STEC shedding in cattle have not provided reliable means of STEC control. Besides feeding studies, other interventions have been suggested as a means of reducing the colonization and shedding of STEC in cattle before slaughter. A US Government Accountability Office report (GAO, 2012) suggested that interventions such as antimicrobial compounds, bacteriophages, colicins, natural product extracts, prebiotics, probiotics, sodium chlorate, and vaccines could be used to reduce STEC shedding. However, the pathogens may develop resistance against antimicrobials, bacteriophages, and colicins. The production of bacteriophages, colicins, probiotics, and natural product extracts (for example, essential oils from citrus peel) in large enough quantities at reasonable cost for use in the large cattle population of the USA is probably not feasible (GAO, 2012). Studies indicate that pre-slaughter treatment of cattle with chlorate (Anderson et al., 2005; Sargeant et al., 2007) or with lactic acid bacteria used as probiotics (Sargeant et al., 2007) can reduce fecal shedding of E. coli O157; however, the results were not consistent. It would appear that these intervention techniques are unreliable as pre-slaughter interventions to reduce serogroup O157 colonization

Non-O157 Shiga toxin-producing E. coli as a foodborne pathogen

17

and shedding in cattle, and the use of these techniques are probably also of limited use in the prevention of shedding of non-O157 STEC. Vaccination studies conducted during the period of 2004 through 2009 focusing on examining the reduction of fecal shedding of O157:H7 were reviewed by Snedeker et al. (2012) and Varela et al. (2013). The vaccines used in the studies were based on type III secreted proteins or on siderophore receptor/porin proteins of E. coli O157:H7. There was a significant reduction in O157:H7 shedding by cattle with both anti-O157 vaccines; however, vaccination did not completely eliminate the organism from the cattle intestinal tract (Snedeker et al., 2012; Varela et al., 2013). Recently, Matthews et al. (2013) modeled the benefits of vaccinating cattle against O157 STEC as a method for the reduction of STEC illness in humans. Their model indicated that vaccination would reduce human disease by approximately 85%. Matthews and her coworkers suggest that super-shedding of O157 STEC by cattle is responsible for most of the STEC cases, and vaccination would reduce super-shedding. However, Gould et al. (2013) and Scallan et al. (2011) indicated that non-O157 STEC are responsible for more STEC disease than O157 STEC in the USA and, in addition, Menrath et al. (2010) have demonstrated that super-shedding cattle can also excrete non-O157 STEC. Development of a vaccine that would prevent the supershedding of O157 and non-O157 STEC may be a feasible means for reducing STEC illness in humans. Through an assessment of the STEC prevalence rate of cattle in three Midwestern beef processing plants, Barkocy-Gallagher et al. (2003) found that the prevalence of O157:H7 STEC was 6.1, 61.0, 27.1, and 1.3% in feces (distal colon), hides, pre-evisceration carcasses, and post-intervention carcasses, respectively. The prevalence rate of non-O157 STEC was 19.4, 56.3, 58.1, and 9.0% in feces (distal colon), hides, pre-evisceration carcasses, and post-intervention carcasses, respectively. The data obtained by BarkocyGallagher et al. (2003) indicate that except for hides, the prevalence of non-O157 STEC was higher than that of O157 STEC. Although Carlson et al. (2008) did not study the decontamination of non-O157 STEC on cattle hides, they did show that spraying with sodium hydroxide (3%, 23 °C), acetic acid (10%, 55 °C), or lactic acid (10%, 55 °C) reduced O157:H7 STEC by at least 2 log CFU cm−2. Elramady et al. (2013) demonstrated that spraying cattle hides contaminated with 6.0 log cfu cm−2 O157:H7 with a mixture of 1% lactic acid and 1% sodium dodecyl sulfate reduced the bacterial numbers by 4.6 log cfu cm−2. Other procedures that have been used to reduce O157:H7 on hides include chemical dehairing, and spraying with cetylpyridinium chloride, ozonated water or electrolyzed water (Koohmaraie et al., 2005). Bosilevac et al., (2006) found that a hot water wash (74 °C) was more effective than a 2% lactic acid wash (ca. 42 °C) in reducing O157:H7 STEC present on pre-evisceration beef carcasses. A ‘multiple’ hurdle approach would appear to be a better means for reducing O157:H7 on beef carcasses (Koohmaraie et al., 2005). After removing the hide, the noneviscerated

18

Advances in microbial food safety

carcass is steam vacuumed followed by a hot water or organic acid wash; after eviscerating and splitting, the carcass is treated with hot water (74 °C) to further cleanse the carcass. A final treatment of hot organic acid or acidified chlorine rinse is applied before removal to the cooler (Koohmaraie et al., 2005). E-beam irradiation (ca. 1 kGy) of O157:H7 inoculated onto the surface of cutaneous trunchi muscle (to simulate the surface of a chilled beef carcass) showed a reduction of ca. 6 log CFU cm−2 (Arthur et al., 2005). However, even though E-beam irradiation appears promising, it has not been used as a means of reducing or eliminating STEC from beef carcasses. STEC serotypes O26:H11, O45:H2, O103:H2, O111:NM, O121:H19, O121:H7, O145:NM, and O157:H7 were inoculated on the surfaces of prerigor beef flanks at 104 CFU cm−2, which were subjected to 15 s of spraying with acidified sodium chlorite (1000 ppm), peroxyacetic acid (200 ppm), lactic acid (4%), or hot water (85 °C) (Kalchayanand et al., 2012). The most effective treatment was hot water spraying, which gave a reduction of STEC levels by ca. 10-fold from a mean of log 4.2 cfu cm−2 (range 3.6 to 4.6) to a mean of log 0.39 (range 0.2 to 0.9). Both non-O157 and O157 behaved similarly to the hot water spray treatment. The data obtained by Kalchayanand et al. (2012) and other workers indicate that STEC present on the surfaces of beef carcasses or meat are not completely removed by various intervention techniques. Thus, it appears that a beef carcass completely free of O157 and non-O157 STEC is difficult to achieve. Rigorous in-plant hygiene involving equipment and personnel is effective in keeping STEC contamination on meat products at a low level. Rigorous personal hygiene, prevention of cross-contamination, proper cooking, and proper storage of meat products must be practiced by consumers.

1.7.1 Prevalence of STEC in meat Between the years 1983 to 2002, state public health laboratories in the USA submitted 940 non-O157 STEC isolates responsible for human infection. Serogroups O26, O45, O103, O111, O121, and O145 accounted for ca. 70% of the infectious agents isolated from individuals with STEC-induced illnesses (Brooks et al., 2005). These six serogroups are considered to be adulterants if present in raw beef products (Federal Register, 2011). Scallan et al. (2011) have estimated that non-O157 STEC are responsible for 64.1% of foodborne illness induced by STEC in the USA. Hussein (2007) assessed world-wide published reports describing the prevalence of STEC in beef cattle and beef products. He demonstrated that the prevalence rates of STEC O157 and non-O157 in beef cattle in feed lots were 0.3 to 19.7% and 4.6 to 55.9%, respectively; prevalence rates for beef cattle on pasture were 0.7 to 27.3% and 4.7 to 44.8%, respectively. Hussein (2007) also determined the prevalence rates of O157 and non-O157 STEC in ground beef, sausages, retail cuts, and whole carcasses. For whole carcasses, the

Non-O157 Shiga toxin-producing E. coli as a foodborne pathogen

19

prevalence rates were 0.1 to 43.4% for O157 and 1.7 to 58.0 for non-O157; for ground beef, they were 0.1 to 54.2 and 2.4 to 30.0; for sausages, the rates were 0.1 to 4.4% and 17.0 to 49.2%; and for various retail cuts, the prevalence rates for O157 were 1.1 to 36.0%, whereas the rates for non-O157 were 11.4 to 49.6%. Barlow et al. (2006) investigated 285 Australian ground beef samples over a one-year period and isolated 46 (16.1%) STEC strains; 95% of the STEC strains were positive for stx2. Ten strains belonged to serogroup O91, and 9 were serogroup O174 (Barlow et al., 2006). Spanish ground beef collected from stores in Lugo, Spain between 1995 and 2003 showed a STEC prevalence of 12.1% (96/785) (Mora et al., 2007). The isolates belonged to 42 O serogroups and 61 O:H serotypes. PCR assays indicated that 28/96 strains were positive for stx1, 49/96 for stx2, and 19/96 carried both stx1 and stx2 genes. Cobbold et al. (2008) determined the presence of STEC in ground beef in the Pacific Northwest over a period of one year; 173/480 samples were positive for the stx gene. STEC were identified in 7.5% (36/480) of the ground beef samples. Serotypes identified included O8, O18, O35, O46, O108, O116, O128, O157, O160, and O175 (Cobbold et al., 2008). The prevalence of STEC strains in 4133 ground beef samples obtained from various areas of the USA over a period of 24 months was determined by Bosilevac and Koohmaraie (2011); stx genes were detected in 24.3% (1006/4133) of the samples. The 300 samples (7.3%; 300/4133) yielded 338 unique STEC isolates comprised of 90 different serotypes. Ju et al. (2012) determined the prevalence of nonO157 STEC in 249 ground beef and 231 ground pork samples from three grocery stores in the Washington, DC, area. STEC was present in 12/231 (5.2%) samples of ground pork and in 13/249 (5.2%) samples of ground beef, 32 different STEC isolates were identified. Ten of the 32 isolates were positive for stx1, and 22 were positive for stx2; stx1 was detected more often in ground pork, whereas stx2 was more common in ground beef. Using PCR assays for serogroups O8, O26, O28, O45, O91, O103, O111, O145, and O157, Ju et al. (2012), found that nine isolates belonged to serogroup O91 (8/231 samples of ground pork and 1/249 ground beef samples); the other isolates did not belong to the serogroups that they targeted.

1.8

Resistance of non-O157 STEC to stress

A bacterium is continually challenged with different environmental conditions. To adapt and survive environmental stress, bacteria utilize global response systems that result in changes in gene expression and cellular metabolism. These responses are controlled by master regulators such as the alternative sigma factor RpoS, the small molecule effector ppGpp, the gene repressor LexA, and the inorganic molecule polyphosphate. The response mechanisms overlap and a particular stress may induce crossprotection to other stresses (Foster, 2007). Food processing, food storage,

20

Advances in microbial food safety

and food preparation provide stressful environments for foodborne bacteria such as the STEC. The most common stresses faced by bacteria present in foods are heat, cold, osmotic pressure, and various acidulants (Chung et al., 2006; Jones, 2012). There is a large body of work concerning the effect of stress on E. coli O157:H7 and how the organism responds to stress (Chung et al., 2006); however, little is known about the effect of stress on non-O157 STEC. A recent review on the effects of various stresses on nonO157 STEC was published by Smith and Fratamico (2012). However, most of the studies discussed in that review were concerned with comparing the effect of stress on STEC O157:H7 to only a few (often one or two) nonO157 STEC serotypes. A study by Luchansky et al. (2011, 2012) demonstrated the effect of grilling of nonintact steaks contaminated with either five strains of O157:H7 STEC or a cocktail of non-O157 STEC serotypes O45:H2, O103:H22, O111:H–, O121:H10, and O145:NM (ca. 5.5 log CFU g−1). The steaks were cooked on an open-flame gas grill to 48.9 to 71.1 °C. Both non-O157 and O157:H7 STEC behaved similarly to grilling; however, even at 71.1 °C, not all of the STEC were inactivated. In another study, Luchansky et al. (2013) compared the heat inactivation of six serotypes of non-O157 STEC with that of O157:H7 inoculated into hamburger patties using an open-flame gas grill or a clamshell electric grill. They found that cooking the patties to an internal temperature of 71.1 or 76.6 °C reduced the STEC levels by 5.1 to 7.0 log cfu g−1. Vasan et al. (2013) compared the heat resistance of non-O157 STEC (O26:H11, O45:H2, O103:H2, O111:H8, O121:H19, and O145:H−) with that of O157:H7 STEC. The D58 values in a beef broth model system of the six non-O157 STEC strains ranged from 0.87 to 1.02 min, compared with 1.02 min for O157:H7. A recent study of the effect of x-ray irradiation of STEC suspended in phosphate-buffered saline (pH 7.0) indicated that the mean D-value for five strains of O157:H7 STEC was 0.074 kGy and that for non-O157 STEC (27 strains) was 0.073 kGy (Kundu et al., 2013). Thus, thermal and radiation data indicate that treatments that inactivate O157:H7 STEC also inactivate non-O157 STEC. There is a paucity of data concerning the effect of stresses on the survival and growth of the non-O157 STEC. The limited amount of published information available suggests that stress interventions utilized in food production and preparation that inactivate O157:H7 also inactivate non-O157 STEC (Kaspar et al., 2010; Mathusa et al., 2010). It is evident that more thorough studies are needed to determine the effect of stresses on nonO157 STEC, examining a wide variety of strains.

1.9

Detection of non-O157 STEC

The USDA Food Safety and Inspection Service (FSIS) classified E. coli O157:H7 as an adulterant in raw ground beef in response to a large

Non-O157 Shiga toxin-producing E. coli as a foodborne pathogen

21

outbreak associated with undercooked ground beef, and in 1994 a verification testing program for this pathogen was established. Evidence has shown that non-O157 STEC, particularly STEC serogroups O26, O45, O103, O111, O121, and O145 cause illnesses similar to those caused by E. coli O157:H7. These STEC serogroups are commonly referred to as the ‘top six’ non-O157 STEC, and they are also an important cause of illness in other countries. Because the top six non-O157 STEC are carried by cattle and thus can contaminate beef, can cause severe illness, may not be destroyed by ordinary cooking, can probably cause illness at low dose, and can spread by person-to-person contact, these STEC serogroups were declared as adulterants in beef trim, and FSIS verification testing for these pathogens began on June 4, 2012 in domestic and imported beef manufacturing trimmings. Expanding the verification testing program to other beef products is being considered. Outbreaks due to non-O157 STEC, including O26 and O111, have been associated with beef, although produce and other foods, as well as animal contact have also been linked to outbreaks (Table 1.2). The method used by the FSIS for non-O157 STEC testing is included in the FSIS Microbiology Laboratory Guidebook (MLG) (http://www.fsis. usda.gov/wps/portal/fsis/topics/science/laboratories-and-procedures/guidebooksand-methods/microbiology-laboratory-guidebook/microbiology-laboratoryguidebook). Because the non-O157 STEC comprise a heterogeneous group of pathogens with phenotypic and genotypic differences, development of methods for detection of these pathogens in beef and other foods has been a challenge. In addition, non-O157 STEC generally ferment sorbitol and are β-glucuronidase positive, unlike O157:H7; therefore, it is difficult to distinguish these pathogens from non-pathogenic E. coli on selective and differential agars that are useful for O157:H7. The method described in the FSIS MLG involves multiplex PCR screening of enrichments for the stx genes and for the eae gene because most strains implicated in HC and HUS carry eae. Primers and probes targeting stx and eae were designed to allow detection of most of the variants of these genes and the DNA extraction method was designed to allow good sensitivity (Wasilenko et al., 2012). However, eae-negative non-O157 STEC, including serogroups O91, O113, and O104, can cause serious illness and have caused outbreaks, and thus vigilant monitoring for emerging non-O157 STEC serogroups is critical. One concern is that samples may be positive for stx1/2 and eae, but the target genes may not be found in the same bacterium (stx1/2 and eae carried by different strains in the sample), thus generating a false positive PCR result. Targeting an additional virulence gene(s) associated with STEC that cause severe disease may partially overcome this problem, and many laboratories throughout the world are working on identifying important STEC virulence markers. Because the phenotypic and biochemical characteristics of STEC vary and, thus, their sensitivity to selective agents used in enrichment media also

22

Advances in microbial food safety

differs, it has been a challenge to identify an enrichment medium suitable for good growth of all STEC while also suppressing growth of background flora. The current FSIS MLG method for non-O157 STEC (MLG 5B.04) describes the use of mTSB without novobiocin to allow simultaneous enrichment of E. coli O157:H7, non-O157 STEC, and Salmonella (FSIS, 2013). Immunomagnetic separation (IMS) is often used to aid in isolation of foodborne pathogens and there is still a need for high-quality antibodies that can be used to prepare IMS and latex reagents, as well as immunologicbased assays for detection and isolation of non-O157 STEC. Finally, there is still no selective and differential agar suitable for isolation of all STEC. Unfortunately, the available agars do not clearly distinguish non-O157 STEC colonies from non-pathogenic E. coli. Furthermore, many agars contain tellurite as a selective agent, and STEC may be sensitive to tellurite, thus their growth is inhibited (Tzschoppe et al., 2012). In one study by Fratamico et al. (2011a), ground beef enrichments were plated onto Rainbow Agar O157 after performing IMS and non-O157 STEC colonies were identified by the colony color; however, strains belonging to some serogroups, including O45 and O103 may have different colony colors. A modified Rainbow Agar O157 (mRBA), containing lower concentrations of potassium tellurite and novobiocin than what is recommended by the manufacturer (mRBA) was developed by Tillman et al. (2012), and this agar was less inhibitory to STEC. Also, the investigators employed a post-IMS acid treatment step before to plating onto mRBA to reduce the level of background flora, which made it easier to isolate the target STEC. Wang et al. (2013) reviewed the current methods, including immunological and DNA-based techniques, developed for detection of non-O157 STEC, and challenges associated with method development were also discussed.

1.10

Conclusions

The non-O157 STEC comprise a diverse group of pathogens found worldwide in ruminants and other animals and in the environment. These pathogens have been associated with sporadic cases and outbreaks of foodborne illness and it is estimated that non-O157 STEC cause a higher number of illnesses than E. coli O157:H7 annually. There are many E. coli serotypes that produce Shiga toxins and these are, therefore, referred to as STEC; however, only a small number of these non-O157 STEC have been associated with severe human illness and outbreaks. More research is needed to better understand STEC virulence mechanisms, their ecology, and their prevalence in animals, food, and the environment. E. coli O157 and nonO157 STEC are apparently similar in their responses to food-related stress and to interventions used during food processing; however, additional research in this area is needed using a variety of strains belonging to

Non-O157 Shiga toxin-producing E. coli as a foodborne pathogen

23

different serogroups and serotypes. Outbreaks caused by non-O157 STEC have been traced to food of bovine origin and produce. Therefore, effective control measures should be developed to reduce STEC colonization and shedding in cattle and to prevent of contamination of meat during slaughter, as well as to prevent contamination of produce during pre- and postharvesting. Methodologies for rapid and reliable detection and for isolation of non-O157 STEC require further development.

1.11

References

Akiba, Y., Kimura, T., Takagi, M., Akimoto, T., Mitsui, Y., Ogasawara, Y. and Omichi, M. (2005) ‘Outbreak of enterohemorrhagic Escherichia coli O121 among school children exposed to cattle in a ranch for Public Education on Dairy Farming’, Jpn. J. Infect Dis., 58, 190–192. Allerberger, F., Friedrich, A. W., Grif, K., Dierich, M. P., Dornbusch, H-J., Mache, C. J., Nachbaur, E., Freilinger, M., Rieck, P., Wagner, M., et al. (2003) ‘Hemolyticuremic syndrome associated with enterohemorrhagic Escherichia coli O26:H¯ infection and consumption of unpasteurized cow’s milk’, Int. J. Infect. Dis., 7, 42–45. Anderson, R. C., Carr, M. A., Miller, R. K., King, D. A., Carstens, G. E., Genovese, K. J., Callaway, T. R., Edrington, T. S. Jung, Y. S., et al. (2005) ‘Effects of experimental chlorate preparations as feed and water supplements on Escherichia coli colonization and contamination of beef cattle and carcasses’, Food Microbiol., 22, 439–447. Arthur, T. M., Wheeler, T. L., Shackelford, S. D., Bosilevac, J. M., Nou, X. and Koohmaraie, M. (2005) ‘Effects of low-dose, low-penetration electron beam irradiation of chilled beef carcass surface cuts on Escherichia coli O157:H7 and meat quality’, J. Food Prot., 68, 666–672. Arthur, T. M., Brichta-Harhay, D. M., Bosilevac, J. M., Kalchayanand, N., Shackelford, S. D., Wheeler, T. L., and Koohmaraie, M. (2010) ‘Super shedding of Escherichia coli O157:H7 by cattle and the impact on beef carcass contamination’, Meat Sci., 86, 32–37. Banatvala, N., Debeukelaer, M. M., Griffin, P. M., Barrett, T. J., Greene, K. D., Green, J. H., and Wells, J. G. (1996) ‘Shiga-like toxin-producing Escherichia coli O111 and associated hemolytic-uremic syndrome: a family outbreak’, Pediatr. Infect. Dis. J., 15, 1008–1011. Barkocy-Gallagher, G. A., Arthur, T. M., Rivera-Betancourt, M., Nou, X., Shackelford, S. D., Wheeler, T. L., and Koohmaraie, M. (2003) ‘Seasonal prevalence of Shiga toxin-producing Escherichia coli, O157:H7 and non-O157 serotypes, and Salmonella in commercial beef processing plants’, J. Food Prot., 66, 1978–1986. Barlow, R. S., Gobius, K. S., and Desmarchelier, P. M. (2006) ‘Shiga toxin-producing Escherichia coli in ground beef and lamb cuts: results of a one-year study’, Int. J. Food Microbiol., 111, 1–5. Berger, C. N., Sodha, S. V., Shaw, R. K., Griffin, P. M., Pink, D., Hand, P., and Frankel, G. (2010) ‘Fresh fruit and vegetables as vehicles for the transmission of human pathogens’, Environ. Microbiol., 12, 2385–2397. Birchard, K. (1999) ‘E. coli O26 outbreak reported in Ireland’, Lancet., 354, 1706. Bosilevac, J. M. and Koohmaraie, M. (2011) ‘Prevalence and characterization of non-O157 Shiga toxin-producing Escherichia coli isolates from commercial ground beef in the United States’, Appl. Environ. Microbiol., 77, 2103–2112.

24

Advances in microbial food safety

Bosilevac, J. M., Nou, X., Barkoxy-Gallagher, G. A., Arthur, T. M. and Koohmaraie, M. (2006) ‘Treaments using hot water instead of lactic acid reduce levels of aerobic bacteria and Enterobacteriaceae and reduce the prevalence of Escherichia coli O157:H7 on preevisceration beef carcasses’, J. Food Prot., 69, 1808–1813. Boudailliez, B., Berquin, P., Mariani-Kurkdjian, P., Ilef D, Cuvelier, B., Capek, L., Tribout, B., Bingen, E., and Piussan, C. (1997) ‘Possible person-to-person transmission of Escherichia coli O111–associated hemolytic uremic syndrome’, Pediatr. Nephrol., 11, 36–39. Bradley, K. K., Williams, J. M., Burnsed, L. J., Lytle, M. B., McDermott, M. D., Mody, R. K., Bhattarai, A., Mallonee, S., Piercefield, E. W., et al. (2012) ‘Epidemiology of a large restaurant-associated outbreak of Shiga toxin-producing Escherichia coli O111:NM’, Epidemiol. Infect. Dis., 140, 1644–1654. Brooks, J. T., Bergmire-Sweat, D., Kennedy, M., Hendicks, K., Garcia, M., Marengo, L., Wells, J., Ying, M., Bibb, W., Griffin, P. M., et al. (2004) ‘Outbreak of Shiga toxin-producing Escherichia coli O111:H8 infections among attendees of a high school cheerleading camp’, Clin. Infect. Dis., 38, 190–198. Brooks, J. T., Sowers, E. G., Wells, J. G., Greene, K. D., Griffin, P. M., Hoekstra, R. M., and Strockbine, N. A. (2005) ‘Non-O157 Shiga toxin-producing Escherichia coli infections in the United States, 1983–2002’, J. Infect. Dis., 192, 1422–1429. Brown, J. A., Hite, D. S., Gillim-Ross, L. A., Maguire, H. F., Bennett, J. K., Patterson, J. J., Comstock, N. A., Watkins, A. K., Ghosh, T. S., and Vogt, R. L. (2012) ‘Outbreak of Shiga toxin-producing Escherichia coli serotype O26:H11 infection at a child care center in Colorado’, Pediatr. Infect. Dis. J., 31, 379–383. Buvens, G. and Piérard, D. (2012) ‘Virulence profiling and disease association of verocytotoxin-produced Escherichia coli O157 and non-O157 isolates in Belgium’, Foodborne Pathog. Dis., 9, 530–535. Buvens, G., Possé, B., De Schrijver, K., De Zutter, L., Lauwers, S., and Piérard, D. (2011) ‘Virulence profiling and quantification of verocytotoxin-producing Escherichia coli O145:H28 and O26:H11 isolated during an ice cream-related hemolytic uremic syndrome outbreak’, Foodborne Pathog. Dis., 8, 421–426. Calderon, V. E., Chang, Q., McDermott, M., Lytle, M. B., McKee, G., Rodiguez, K., Rasko, D. A., Sperandio, V., and Torres, A. G. (2010) ‘Outbreak caused by cadnegative Shiga toxin-producing Escherichia coli O111, Oklahoma’, Foodborne Pathog. Dis., 7, 107–109. Callaway, T. R., Carr, M. A., Edrington, T. S., Anderson, R. C., and Nisbet, D. J. (2009) ‘Diet, Escherichia coli O157:H7, and cattle: a review after 10 years’, Curr. Issues Mol. Biol., 11, 67–80. Caprioli, A., Luzzi, I., Rosmini, F., Resti, C., Edefonti, A., Perfumo, F., Farina, C., Goglio, A., Gianviti, A., and Rizzoni, G. (1994) ‘Communitywide outbreak of hemolytic–uremic syndrome associated with non-O157 verocytotoxin-producing Escherichia coli’, J. Infect. Dis., 169, 208–211. Caprioli, A., Morabito, S., Brugère, H., and Oswald, E. (2005) ‘Enterohaemorrhagic Escherichia coli: emerging issues on virulence and modes of transmission’, Vet. Res., 36, 289–311. Carlson, B. A., Ruby, J., Smith, G. C., Sofos, J. N., Bellinger, G. R., Warren-Serna, W., Centrella, B., Bowling, R. A., and Belk, K. E. (2008) ‘Comparison of antimicrobial efficacy of multiple beef hide decontamination strategies to reduce levels of Escherichia coli O157:H7 and Salmonella’, J. Food Prot., 71, 2223–2227. CDC (1995a) ‘Community outbreak of hemolytic uremic syndrome attributable to Escherichia coli O111:NM – South Australia, 1995’, MMWR, 44, 550–551, 557–558. CDC (1995b) ‘Outbreak of acute gastroenteritis attributable to Escherichia coli serotype O104:H21 – Helena, Montana, 1994’, MMWR, 44, 501–503.

Non-O157 Shiga toxin-producing E. coli as a foodborne pathogen

25

CDC (2000) ‘Escherichia coli O111:H8 outbreak among teenage campers – Texas, 1999’, MMWR, 49, 321–324. CDC (2006) ‘Importance of culture confirmation of Shiga toxin-producing Escherichia coli infection as illustrated by outbreaks of gastroenteritis – New York and North Carolina, 2005’, MMWR, 55, 1042–1045. CDC (2012) ‘Outbreak of Shiga toxin-producing Escherichia coli O111 infections associated with a correctional facility dairy – Colorado, 2010’, MMWR, 61, 149–152. CDC (2013) ‘Incidence and trends of infection with pathogens transmitted commonly through food – Foodborne Diseases Active Surveillance Network, 10 U.S. sites, 1996–2012’, MMWR, 62, 283–287. Chase-Topping, M., Gally, D., Low, C., Matthews, L., and Woolhouse, M. (2008) ‘Super-shedding and the link between human infection and livestock carriage of Escherichia coli O157’, Nat. Rev. Microbiol., 6, 904–912. Cho, S., Diez-Gonzalez, F., Fossler, C. P., Wells, S. J., Hedberg, C. W., Kaneene, J. B., Ruegg, P. L., Warnick, L. D., and Bender, J. B. (2006) ‘Prevalence of Shiga toxinencoding bacteria and Shiga toxin-producing Escherichia coli isolates from dairy farms and county fairs’, Vet. Microbiol., 118, 289–298. Chung, H. J., Bang, W., and Drake, M. A. (2006) ‘Stress response of Escherichia coli’, Compr. Rev. Food Sci. F, 5, 52–64. Cobbold, R. N., Davis, M. A., Rice, D. H., Szymanski, M., Tarr, P. I., Besser, T. E., and Hancock, D. D. (2008) ‘Associations between bovine, human, and raw milk, and beef isolates of non-O157 Shiga toxigenic Escherichia coli within a restricted geographic area of the United States’, J. Food Prot., 71, 1023–1027. Cooley, M., Carychao, D., Crawford-Miksza, L., Jay, M. T., Myers, C., Rose, C., Keys, C., Farrar, J., and Mandrell, R. E. (2007) ‘Incidence and tracking of Escherichia coli O157:H7 in a major produce production region in California’, PLoS ONE, 2, e1159. Craun G. F., Calderon, R. L., and Craun, M. F. (2005) ‘Outbreaks associated with recreational water in the United States’, J. Environ. Health Res., 15, 243–262. Dallman, T, Smith, G. P., O’Brien, B., Chattaway, M. A., Finlay, D., Grant, K. A., and Jenkins, C. (2012) ‘Characterization of a verocytotoxin-producing enteroaggregative Escherichia coli serogroup O111:H21 strain associated with a household outbreak in Northern Ireland’, J. Clin. Microbiol., 50, 4116–4119. Dargatz, D. A., Bai, J., Lubbers, B. V., Kopral, C. A., An, B., and Anderson, G. A. (2013) ‘Prevalence of Escherichia coli O-types and Shiga-toxin genes in fecal samples from feedlot cattle’, Foodborne Pathog. Dis., 10, 392–396. De Schrijver, K., Buvens, G., Possé, B., Van den Branden, D., Oosterlynck, O., De Zutter, L., Eilers, K., Piérard, D., et al. (2008) ‘Outbreak of verocytotoxinproducing E. coli O145 and O26 infections associated with the consumption of ice cream produced at a farm, Belgium, 2007’, Euro Surveill., 13(7):pii=8041. Available online: http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=8041. Diercke, M., Kirchner, M., Claussen, K., Mayr, E., Strotmann, I., Frangenberg, J., Schiffmann, A., Bettge-Weller, G., Arvand, M., and Uphoff, H. (2013) ‘Transmission of Shiga toxin-producing Escherichia coli O104:H4 at a family party possibly due to contamination by a food handler, Germany 2011’, Epidemiol. Infect., 142, 99–106. DOI:10.1017/S0950268813000769. EFSA (European Food Safety Authority) (2011) ‘Urgent advice on the public health risk of Shiga-toxin producing Escherichia coli in fresh vegetables’, EFSA J., 9, 2274. doi:10.2903/j.efsa.2011.2274. EFSA (European Food Safety Authority) (2013) ‘EFSA Panel on Biological Hazards (BIOHAZ); scientific opinion on VTEC-seropathotype and scientific criteria regarding pathogenicity assessment’, EFSA J., 11, 3138. DOI:10.2903/ j.efsa.2013.3138.

26

Advances in microbial food safety

Elramady, M. G., Aly, S. S., Rossitto, P. V., Crook, J. A. and Cullor, J. S. (2013) ‘Synergistic effects of lactic acid and sodium dodecyl sulfate to decontaminate Escherichia coli O157:H7 on cattle hide sections’, Foodborne Pathog. Dis., 10, 661–662. Espié, E, Grimont, F., Vaillant, V., Montet, M. P., Carle, I., Bavai, C., de Valk, H, and Vernozy-Rozand, C. (2006) ‘O148 Shiga toxin-producing Escherichia coli outbreak: microbiological investigation as a useful complement to epidemiological investigation’, Clin., Microbiol. Infect., 12, 992–998. Ethelberg, S., Smith, B., Torpdahl, M., Lisby, M., Boel, J., Jensen, T., Nielsen, E. M. and Mølbak, K. (2009) ‘Outbreak of non-O157 Shiga toxin-producing Escherichia coli infection from consumption of beef sausage’, Clin. Infect. Dis., 48, 78–81. Federal Register (2011) Shiga toxin-producing Escherichia coli in certain raw beef products, (USDA, FSIS, 9 CFR Parts 416, 417, and 430. 76 (No. 182), 58157–58165. Fernández, D., Irino, K., Sanz, M. E., Padola, N. L., and Parma, A. E. (2010) ‘Characterization of Shiga toxin-producing Escherichia coli isolated from dairy cows in Argentina’, Lett. Appl. Microbiol., 51, 377–382. Foster, P. L. (2007) ‘Stress-induced mutagenesis in bacteria’, Crit Rev. Biochem. Mol. Biol., 42, 373–397. Frank, C., Kaphammer, S., Werber, D., Stark, K. and Held, L. (2008) ‘Cattle density and Shiga toxin-producing Escherichia coli infection in Germany: increased risk for most but not all serogroups’, Vector Borne Zoonotic Dis., 8, 635–643. Fratamico, P. M., Bagi, L. K., Cray, W. C. Jr., Narang, N., Yan, X., Medina, M., and Liu, Y. (2011a) ‘Detection by multiplex real-time polymerase chain reaction assays and isolation of Shiga toxin-producing Escherichia coli serogroups O26, O45, O103, O111, O121, and O145 in ground beef’, Foodborne Pathog. Dis., 8, 601–607. Fratamico, P. M., Yan, X., Caprioli, A., Esposito, G., Needleman, D. S., Pepe, T., Tozzoli, R., Cortesi, M. L., and Morabito, S. (2011b) ‘The complete DNA sequence and analysis of the virulence plasmid and of five additional plasmids carried by Shiga toxin-producing Escherichia coli O26:H11 strain H30’, Int. J. Med. Microbiol., 301, 192–203. FSIS (2012), Risk profile for pathogenic non-O157 Shiga toxin-producing Escherichia coli (non-O157 STEC). Available from: http://www.fsis.usda. gov/PDF/Non_O157_STEC_Risk_Profile_May2012.pdf. Accessed 16 February 2014. FSIS (2013). Detection and isolation of non-O157 Shiga toxin-producing Escherichia coli (STEC) from meat products and carcass and environmental sponges. U.S. Department of Agriculture, Food Safety and Inspection Service. Available at http://www.fsis.usda.gov/wps/wcm/connect/7ffc02b5-3d33-4a79-b50c81f208893204/MLG-5B.pdf?MOD=AJPERES. Accessed 16 February 2014. Gallo, G. E. and Gianantonio, C. A. (1995) ‘Extrarenal involment in diarrheaassociated haemolytic–uraemic syndrome’, Pediatr.Nephrol., 9, 117–119. GAO (U. S. Government Accountability Office) (2012) ‘Preslaughter interventions could reduce E. coli in cattle’, GAO, 12(257), 29 pages. Gould, L. H., Mody, R. K., Ong, K. L., Clogher, P., Cronquist, A. B., Garman, K. N., Lathrop, S., Medus, N. L., Spina, C., Webb, T. H., et al. (2013) ‘Increased recognition of non-O157 Shiga toxin-producing Escherichia coli infections in the United States during 2000–2010: Epidemiologic features and comparison with E. coli O157 infections’, Foodborne Pathog. Dis., 10, 453–460. Gyles, C. L. (2007) ‘Shiga toxin-producing Escherichia coli: an overview’, J. Anim. Sci., 85, E45–E62. Hale, C. R., Scallan, E., Cronquist, A. B., Dunn, J., Smith, K., Robinson, T., Lathrop, S., Tobin-D’Angelo, M., and Clougher, P. (2012) ‘Estimates of enteric illness

Non-O157 Shiga toxin-producing E. coli as a foodborne pathogen

27

attributable to contact with animals and their environments in the United States’, Clin. Infect. Dis., 54, (Suppl 5), S472–S479. Hashimoto, H., Mizukoshi, K., Nishi, M., Kawakita, T., Hasui, S., Kato, Y., Ueno, Y., Takeya, R., Okuda, N., and Takeda, T. (1999) ‘Epidemic of gastrointestinal tract infection including hemorrhagic colitis attributable to Shiga toxin 1-producing Escherichia coli O118:H2 at a junior high school in Japan’, Pediatrics, 103, e2. Haus-Cheymol, R., Espie, E., Che, D., Vaillant, V., De Valk, H., and Desenclos, J. C. (2006) ‘Association between indicators of cattle density and incidence of paediatrichaemolytic–uraemic syndrome (HUS) in children under 15 years of age in France between 1996 and 2001: an ecological study’, Epidemiol. Infect., 134, 712–718. Hiruta, N., Murase, T, and Okamura, N. (2000) ‘An outbreak of diarrhea due to multiple antimicrobial-resistant Shiga toxin-producing Escherichia coli O26:H11 in a nursery’, Epidemiol. Infect., 127, 221–227. Hoshina, K., Itagaki, A., Seki, R., Yamamoto, K., Masuda, S., Muku, T., and Okada, N. (2001) ‘Enterohemorrhagic Escherichia coli O26 outbreak caused by contaminated natural water supplied by facility owned by local community’, Jpn. J. Infect. Dis., 54, 247–248. Hussein, H. S. (2007) ‘Prevalence and pathogenicity of Shiga toxin-producing Escherichia coli in beef cattle and their products’, J. Anim. Sci., 85, E63–E72. Hussein, H. S. and Bollinger, L. M. (2005) ‘Prevalence of Shiga toxin-producing Escherichia coli in beef cattle’, J. Food Prot., 68, 2224–2241. Hussein, H. S. and Sakuma T. (2005) ‘Prevalence of Shiga toxin-producing Escherichia coli in dairy cattle and their products’, J. Dairy Sci., 88, 450–465. Imamovic, L., Tozzoli, R., Michelacci, V., Minelli, F., Marziano, M. L., Caprioli, A., and Morabito, S. (2010) ‘OI-57, a genomic island of Escherichia coli O157, is present in other seropathotypes of Shiga toxin-producing E. coli associated with severe human disease’, Infect. Immunol., 78, 4697–4704. INVS (Institut de Veille Sanitaire) (2007) Epidémie d’infections à E. coli producteurs de Shiga-toxines non O157 liée à la consommation de camembert au lait cru, nord-ouest de la France, octobre–décembre 2005 http://www.invs.sante.fr/ publications/2008/epidemie_e_coli_camembert/rapport_epidemie_stec.pdf. Accessed 16 February 2014. Irino K., Vieira, M. A., Gomes, T. A., Guth, B. E., Naves, Z. V., Oliveira, M. G., dos Santos, L. F., Guirro, M., Timm, C. D., et al. (2010) ‘Subtilasecytotoxin-encoding subAB operon found exclusively among Shiga toxin-producing Escherichia coli strains’, J. Clin. Microbiol., 48, 988–990. Ivarsson, M. E., Leroux, J-C., and Castagner, B. (2012) ‘Targeting bacterial toxins’, Angew. Chem. Int. Ed. Engl., 51, 4024–4045. Jacob, M. E., Callaway, T. R., and Nagaraja, T. G. (2009) ‘Dietary interactions and interventions affecting Escherichia coli O157 colonization and shedding in cattle’, Foodborne Pathog. Dis., 6, 785–792. Jay, M. T., Cooley, M., Carychao, D., Wiscomb, G. W., Sweitzer, R. A., CrawfordMiksza, L., Farrar, J. A., Lau, D. K., et al. (2007) ‘Escherichia coli O157:H7 in feral swine near spinach fields and cattle, Central California Coast’, Emerg. Infect. Dis., 13, 1908–1911. Jeon, B-W., Jeong, J-M., Won, G-Y., Park, H., Eo, S-K., Kang, H-Y., Hur, J., and Lee, J. H. (2006) ‘Prevalence and characteristics of Escherichia coli O26 and O111 from cattle in Korea’, Int. J. Food Microbiol., 110, 123–126. Jones, T. H. (2012), ‘Response of Escherichia coli to environmental stress’, in H-C. Wong, Stress response of foodborne microorganisms, Happauge, Nova Science Publishers, Inc., 52–75. Jourdan-da Silva, N., Watrin, M., Weill, F. X., King, L. A., Gouali, M., Mailles, A., van Cauteren, D., Bataille, M., Guettier, S., et al. (2012) ‘Outbreak of haemolytic

28

Advances in microbial food safety

uraemic syndrome due to Shiga toxin-producing Escherichia coli O104:H4 among French tourists returning from Turkey, September 2011’, Euro Surveill., 17(4), pii: 20065. Ju, W., Shen, J., Li, Y., Toro, M. A., Zhao, S., Ayers, S., Najjar, M. B., and Meng, J. (2012) ‘Non-O157 Shiga toxin-producing Escherichia coli in retail ground beef and pork in the Washington, D.C. area’, Food Microbiol., 32, 371–377. Ju, W, Shen, J., Toro, M., Zhao, S., and Meng, J. (2013) ‘Distribution of pathogenicity islands OI-122, OI-43/48, and OI-57 and a high-pathogenicity island in Shiga toxin-producing Escherichia coli’, Appl. Environ.Microbiol., 79, 3406–3412. Kalchayanand, N, Arthur, T. M., Bosilevac, J. M., Schmidt, J. W., Wang, R., Shackelford, S. D., and Wheeler, T. L. (2012) ‘Evaluation of commonly used antimicrobial interventions for fresh beef inoculated with Shiga toxin-producing Escherichia coli serotypes O26, O45, O103, O111, O121, O145, and O157:H7’, J. Food Prot., 75, 1207–1212. Karch, H., Bielaszewska, M., Bitzan, M., and Schmidt, H. (1999) ‘Epidemiology and diagnosis of Shiga toxin-producing Escherichia coli infections’, Diagn.Microbiol. Infect. Dis., 34, 229–243. Karch, H., Tarr, P. I., and Bielaszewska, M. B. (2005) ‘Enterohaemorrhagic Escherichia coli in human medicine’, Int. J. Med. Microbiol., 295, 405–418. Karmali, M. A., Mascarenhas, M., Shen, S., Ziebell, K., Johnson, S., Reid-Smith, R., Isaac-Renton, J., Clark, C., Rahn, K., and Kaper, J. B. (2003) ‘Association of genomic O island 122 of Escherichia coli EDL933 with verocytotoxin-producing seropathotypes that are linked to epidemic and/or serious disease’, J. Clin. Microbiol., 41, 4930–4940. Kase, J. A., Maounounen-Laasri, A., Son, I., Deer, D. M., Borenstein, S., Prezioso, S., and Hammack, T. S. (2012a) ‘Comparison of different sample preparation procedures for the detection and isolation of Escherichia coli O157:H7 and non-O157 STECs from leafy greens and cilantro, Food Microbiol., 32, 423–426. Kase, J. A., Borenstein, S., Blodgett, R. J., and Feng, P. C. H. (2012b) ‘Microbial quality of bagged baby spinach and romaine lettuce: effect of top versus bottom sampling’, J. Food Prot., 75, 132–136. Kaspar, C., Doyle, M. E., and Archer, J. (2010) White paper on non-O157:H7 Shiga toxin-producing E. coli from meat and non-meat sources. Available from: http:// fri.wisc.edu/docs/pdf/FRI_Brief_NonO157STEC_4_10.pdf (accessed 16 February 2014). Kato, K., Shimoura, R., Nashimura, K., Yoshifuzi, K., Shiroshita, K., Sakurai, N., Kodama, H., and Kuramoto, S. (2005) ‘Outbreak of enterohemorrhagic Escherichia coli O111 among high school participants in excursion to Korea’, Jpn. J. Infect. Dis., 58, 332–333. Khan, A. B. and Naim, A. (2011) ‘Virulence traits of Shiga toxin producing Escherichia coli’, the Health, 2, 119–127. King, L. A., Filliol-Toutain, I., Mariani-Kurkidjian, P., Vaillant, V., Vernozy-Rozand, C., Ganet, S., Pihier, N., Niaudet, P., and de Valk, H. (2010) ‘Family outbreak of Shiga toxin-producing Escherichia coli O123:H−, France, 2009’, Emerg. Infect. Dis., 16, 1491–1493. Kobayashi, H., Kanazaki, M., Ogawa, T., Iyoda, S. and Hara-Kudo, Y. (2009) ‘Changing prevalence of O-serogroups and antimicrobial susceptibility among STEC strains isolated from healthy dairy cows over a decade in Japan between 1998 and 2007’, J. Vet. Med. Sci., 71, 363–366. Konczy, P., Ziebell, K., Mascarenhas, M., Choi, A., Michaud, C., Kropinski, A. M., Whittam, T. S., Wickham, M., Finlay, B., and Karmali, M. A. (2008) ‘Genomic O island 122, locus for enterocyte effacement, and the evolution of virulent verocytotoxin-producing Escherichia coli’, J. Bacteriol., 190, 5832–5840.

Non-O157 Shiga toxin-producing E. coli as a foodborne pathogen

29

Koohmaraie, M., Arthur, T. M., Boselevac, J. M., Guerini, M., Shackelford, S. D., and Wheeler, T. L. (2005) ‘Post-harvest interventions to reduce/eliminate pathogens in beef’, Meat Sci., 71, 79–91. Kundu, D., Gill, A., and Holley, R. (2013) ‘Use of low-dose irradiation to evaluate the radiation sensitivity of Escherichia coli O157:H7, non-O157 verotoxigenic Escherichia coli, and Salmonella in phosphate-buffered saline’, J. Food Prot., 76, 1438–1442. Lara-Ochoa, C., Oropeza, R,, and Huerta-Saquero, A. (2010), ‘Regulation of the LEE-pathogenicity island in attaching and effacing bacteria’ in A. Méndez-Vila, Current research, technology and education topics in applied microbiology and microbial technology, Vol. 1, p. 635–645. Available from: http://www.formatex.info/ microbiology2/635-645.pdf. Accessed 16 February 2014. Luchansky, J. B., Porto-Fett, A. C. S., Shoyer, B. A., Call, J. E., Schlosser, W., Bauer, N., and Latimer, H. (2011) ‘Inactivation of Shiga toxin-producing O157:H7 and non-O157:H7 Escherichia coli in brine-injected, gas-grilled steaks’, J. Food Prot., 74, 1054–1064 Luchansky, J. B., Porto-Fett, A. C. S., Shoyer, B. A., Call, J. E., Schlosser, W., Bauer, N., and Latimer, H. (2012) ‘Fate of Shiga toxin-producing O157:H7 and nonO157:H7 Escherichia coli within blade tenderized beef steaks after cooking on a commercial open-flame gas grill’, J. Food Prot., 75, 62–70. Luchansky, J. B., Porto-Fett, A. C. S., Shoyer, B.A., Phillips, J., Chen, V., Eblen, E. R., Cook, L. V., Mohr, T. B., Esteban, E. and Bauer, N. (2013) ‘Fate of Shiga toxinproducing O157:H7 and non-O157:H7 Escherichia coli cells within refrigerated, frozen, or frozen then thawed ground beef patties cooked on a commercial openflame gas or a clamshell electric grill’, J. Food Prot., 76, 1500–1512. Mariani-Kurkdjian, P., Denamur, E., Milon, A., Picard, B., Cave, H., LambertZechovsky, N., Loirat, C., Goullet, P., Sansonetti, P. P., and Elion, J. (1993) ‘Identification of a clone of Escherichia coli O103:H2 as a potential agent of hemolytic–uremic syndrome in France’, J. Clin. Microbiol., 31, 296–301. Mathusa, E. C., Chen, Y., Enache, E., and Hontz, L. (2010) ‘Non-O157 Shiga toxinproducing Escherichia coli in foods’, J. Food Prot., 73, 1721–1736. Matthews, L., Reeve, R., Gally, D. L., Low, J. C., Woolhouse, M. E. J., McAteer, S. P., Locking, M. E., Chase-Topping, M. E., Haydon, D. T. et al. (2013) ‘Predicting the public health benefit of vaccinating cattle against Escherichia coli’, Proc. Natl. Acad. Sci. USA, 110, 16265–16270. McCarthy, T. A., Barrett, N. L., Hadler, J. L., Salsbury, B., Howard, R. T., Dingman, D. W., Brinkman, C. D., Bibb, W. F., and Cartter, M. L. (2001) ‘Hemolytic–uremic syndrome and Escherichia coli O121 at a Lake in Connecticut, 1999’, Pediatrics, 108, e59. McMaster, C., Roch, E. A., Willshaw, G. A., Doherty, A., Kinnear, W., and Cheasty, T. (2001) ‘Verotoxin-producing Escherichia coli serotype O26:H11 outbreak in an Irish crèche’, Eur. J. Clin. Microbiol. Infect. Dis., 20, 430–432. Menrath, A., Wieler, L. H., Heidemanns, K., Semmler, T., Fruth, A., and Kemper, N. (2010) ‘Shiga toxin producing Escherichia coli: identification of non-O157:H7super-shedding cows and related risk factors’, Gut Pathog, 2, 7. Misselwitz, J., Karch, H., Bielazewska, M., John, U., Ringelmann, F., Rönnefarth, G., and Patzer, L. (2003) ‘Cluster of hemolytic–uremic syndrome caused by Shiga toxin-producing Escherichia coli O26:H11’, Pediatr. Infect. Dis. J., 22, 349–354. Miyajima, Y., Takahashi, M., Eguchi, H., Honma, M., Tanahashi, S., Matui, Y., Kobayashi, G., Tanaka, M., Higuchi, T., and Takeuchi, Y. (2007) ‘Outbreak of enterohemorrhagic Escherichia coli O26 in Niigata City, Japan’, Jpn. J. Infect. Dis., 60, 238–239. Møller-Stray, J., Eriksen, H. M., Bruhelm, T., Kapperud, G., Lindstedt, B. A., Skele, Å., Sunde, M., Urdahl, A. M., Øygard, B., and Vold, L. (2012) ‘Two outbreaks of

30

Advances in microbial food safety

diarrhea in nurseries in Norway after farm visits, April to May 2009’, Euro Surveill., 17(47):pii=20321. Available online: http://www.eurosurveillance.org/ ViewArticle.aspx?ArticleId=20321 Monaghan, Á., Byrne, B., Fanning, S., Sweeney, T., McDowell, D., and Bolton, D. J. (2011) ‘Serotypes and virulence profiles of non-O157 Shiga toxin-producing Escherichia coli isolates from bovine farms’, Appl. Environ. Microbiol., 77, 8662–8668. Mora, A., Blanco, M., Blanco, J. E., Dabbi, G., López, C., Justel, P., Alonso, M. P., Echeita, A., Bernárdez, M. I., González, E. A., and Blanco, J. (2007) ‘Serotypes, virulence genes and intimin types of Shiga toxin (verocytotoxin)-producing Escherichia coli isolates from minced beef in Lugo (Spain) from 1995 through 2003’, BMC Microbiol., 7, 13. Mora, A., López, C., Dhabi, G., López-Beceiro, A. M., Fidalgo, L. E., Diaz, E. A., Martinez-Carrasco, C., Mamani, R., Herrera, A., Blanco, J. E., Blanco, M., and Blanco, J. (2012) ‘Seropathotypes, phylogroups, stx subtypes, and intimin types of wildlife-carried, Shiga toxin-producing Escherichia coli strains with the same characteristics as human pathogenic types’, Appl. Environ. Microbiol., 78, 2578–2585. Morabito, S., Karch, H., Mariani-Kurkdjian, P., Schmidt, H., Minelli, F., Bingen, E., and Caprioli, A. (1998) ‘Enteroaggregative, Shiga toxin-producing Escherichia coli O111:H2 associated with an outbreak of hemolytic–uremic syndrome’, J. Clin. Microbiol., 36, 840–842. Muraoka, R., Okazaki, J., Fujimoto, Y., Jo, N., Yoshida, R., Kiyoyama, T., Oura, Y., Hirakawa, K., Jyukurogi, M., Kawano, K., et al. (2007) ‘An enterohemorrhagic Escherichia coli O103 outbreak at a nursery school in Miyazaki Prefecture, Japan’, Jpn. J. Infect. Dis., 60, 410–411. Newton, H. J., Sloan, J., Bulach, D. M., Seemann, T., Allison, C. C., Tauschek, M., Robins-Browne, R. M., Paton, J. C., Whittam, T. S., Paton, A. W., and Hartland, E. L. (2009) ‘Shiga toxin-producing Escherichia coli strains negative for locus of enterocyte effacement’, Emerg. Infect. Dis., 15, 272–380. Nwachuku, N. and Gerba, C. P. (2008) ‘Occurrence and persistence of Escherichia coli O157:H7 in water’, Rev. Environ. Sci. Biotechnol., 7, 267–273. Oporto, B., Esteban, J. I., Aduriz, G., Just, R. A., and Hurtado, A. (2008) ‘Escherichia coli O157:H7 and non-O157 Shiga toxin-producing E. coli in healthy cattle, sheep, and swine herds in northern Spain’, Zoonoses Public Health, 55, 73–81. Paton, A. W., Ratcliff, R. M., Doyle, R. M., Seymour-Murray, J., Davos, D., Lanser, J. A., and Paton, J. C. (1996) ‘Molecular microbiological investigation of an outbreak of hemolytic–uremic syndrome caused by dry fermented sausage contaminated with Shiga-like toxin-producing Escherichia coli’, J. Clin. Microbiol., 34, 1622–1627. Paton, A. W., Srimanote, P., Woodrow, M. C., and Paton, J. C. (2001) ‘Characterization of Saa, a novel autoagglutinatin adhesion produced by locus of enterocyte effacement-negative Shiga-toxigenic Escherichia coli strains that are virulent for humans’, Infect. Immunol., 69, 6999–7009. Paton, A. W., Woodrow, M. C., Doyle, R. M., Lanser, J. A., and Paton, J. C. (1999) ‘Molecular characterization of a Shiga toxigenic Escherichia coli O113:H21 strain lacmissel eae responsible for a cluster of cases of hemolytic–uremic syndrome’, J. Clin. Microbiol., 37, 3357–3361. Pearce, M. C., Evans, J., Mckendrick, I. J., Smith, A. W., Knight, H. I., Mellor, D. J., Woolhouse, M. E., Gunn, G. J., and Low, J. C. (2006) ‘Prevalence and virulence factors of Escherichia coli serogroups O26, O103, O111, and O145 shed by cattle in Scotland’, Appl. Environ. Microbiol., 72, 653–659.

Non-O157 Shiga toxin-producing E. coli as a foodborne pathogen

31

Piercefield, E. W., Bradley, K. K., Coffman, R. L., and Mallonee, S. M. (2010) ‘Hemolytic uremic syndrome after an Escherichia coli O111 outbreak’, Arch. Intern. Med., 107, 1656–1663. Rounds, J. M., Rigdon, C. E., Muhl, L. J., Forstner, M., Danzeisen, G. T., Koziol, B. S., Taylor, C., Shaw, B. T., Short, G. L., and Smith, K. E. (2012) ‘Non-O157 Shiga toxin-producing Escherichia coli associated with venison’, Emerg. Infect. Dis., 18, 279–282. Sargeant, J. M., Amezcua, M. R., Rajic, A. and Waddell, L. (2007) ‘Pre-harvest interventions to reduce the shedding of E. coli O157 in the faeces of weaned domestic ruminants: a systematic review’, Zoonoses Public Health., 54, 260–277. Sayers, G., McCarthy, T., O’Connell, M., O’Leary, M., O’Brien, D., Cafferkey, M. and McNamara, E. (2006) ‘Haemolytic uraemic syndrome associated with interfamilial spread of E. coli O26:H11, Epidemiol. Infect., 134, 724–728. Scallan, E., Hoekstra, R. M., Angulo, F. J., Tauxe, R. V., Widdowson, M. A., Roy, S. L., Jones, J. L. and Griffin, P. M. (2011) ‘Foodborne illness acquired in the United States – major pathogens’, Emerg. Infect. Dis., 17, 7–14. Schaffzin, J. K., Coronado, F., Dumas, N. B., Root, T. P., Halse, T. A., SchoonmakerBopp, D. J., Lurie, M. M., Nicholas, D., et al. (2012) ‘Public health approach to detection of non-O157 Shiga toxin-producing Escherichia coli: summary of two outbreaks and laboratory procedures’, Epidemiol. Infect., 140, 283–289. Schimmer, B., Nygard, K., Eriksen, H-M., Lassen, J., Lindstedt, B-A., Brandal, L. T., Kapperud, G., and Aavitsland, P. (2008) ‘Outbreak of haemolytic uraemic syndrome in Norway caused by stx2-positive Escherichia coli O103:H25 traced to cured mutton sausages’, BMC Infect. Dis., 8, 41. Slayton, R. B., Turabelidze, G., Bennett, S. D., Schwensohn, C. A., Yaffee, A. Q., Khan, F., Butler, C., Trees, E., Ayers, T. L., et al. (2013) ‘Outbreak of Shiga toxinproducing Escherichia coli (STEC) O157:H7 associated with romaine lettuce consumption, 2011, PLOS One, 8, e55300. Smith, J. L. and Fratamico, P. M. (2012) ‘Effect of stress on non-O157 Shiga toxinproducing Escherichia coli’, J. Food Prot., 75, 2241–2250. Snedeker, K. G., Campbell, M., and Sargeant, J. M. (2012) ‘A systemic review of vaccinations to reduce the shedding of Escherichia coli O157 in the faeces of domestic ruminants’, Zoonoses Public Health, 59, 126–138. Söderström, A., Österberg, P., Lindqvist, A., Jönsson, B., Lindberg, A., Ulander, S. B., Welinder-Olsson, C., Löfdahl, S., Kaijser, B., et al. (2008) ‘A large Escherichia coli O157:H7 outbreak in Sweden associated with locally produced lettuce’, Foodborne Pathog. Dis., 5, 339–349. Sonoda, C., Tagami, A., Nagatomo, D., Yamada, S., Fuchiwaki, R., Haruyama, M., Nakamura, Y., Kawano, K., Okada, M., et al. (2008) ‘An enterohemorrhagic Escherichia coli O26 outbreak at a nursery school in Miyazaki, Japan’, Jpn. J. Infect. Dis., 61, 92–93. Takanashi, J.-I., Taneichi, H., Misaki, T., Yahata, Y., Okumura, A., Ishiada, Y.-I., Miyawaki, T., Okabe, N., Sata, T., and Mizuguchi, M. (2014) ‘Clinical and radiologic features of encephalopathy during 2011 E. coli O111 outbreak in Japan’, Neurology, 82, 564–572. Tanaro, J. D., Galli, L., Lound, L. H., Leotta, G. A., Piaggio, M. C., Carbonari, C. C., Irino, K., and Rivas, M. (2012) ‘Non-O157:H7 Shiga toxin-producing Escherichia coli in bovine rectums and surface water streams on a beef cattle farm in Argentina’, Foodborne Pathog. Dis., 9, 878–884. Taylor, E. V., Nguyen, T. A., Machesky, K. D., Koch, E., Sotir, M. J., Bohm, S. R., Folster, J. P., Rokanyhi, R., Kupper, A., Bidol, S. A., et al. (2013) ‘Multistate outbreak of Escherichia coli O145 infections associated with romaine lettuce consumption, 2010’, J. Food Prot., 76, 939–944.

32

Advances in microbial food safety

Tillman, G. E.,Wasilenko, J. L., Simmons, M., Lauze, T. A, Minicozzi, J., Oakley, B. B., Narang, N., Fratamico, P., Cray, W. C, Jr. (2012) ‘Isolation of Shiga toxinproducing Escherichia coli serogroups O26, O45, O103, O111, O121, and O145 from ground beef using modified rainbow agar and post-immunomagnetic separation acid treatment’, J. Food Prot.,75, 1548–1554. Tzschoppe, M., Martin, A., Beutin, L. (2012) ‘A rapid procedure for the detection and isolation of enterohaemorrhagic Escherichia coli (EHEC) serogroup O26, O103, O111, O118, O121, O145 and O157 strains and the aggregative EHEC O104:H4 strain from ready-to-eat vegetables’ Int. J. Food Microbiol., 152, 19–30. Valcour, J. E., Michel, P., McEwen, S. A., and Wilson, J. B. (2002) ‘Association between indicators of livestock farming intensity and incidence of human Shiga toxinproducing Escherichia coli infection’, Emerg. Infect. Dis., 8, 252–257. Varela, N. P., Dick, P., and Wilson, J. (2013) ‘Assessing the existing information on the efficacy of bovine vaccination against Escherichia coli O157:H7 – a systematic review and meta-analysis’, Zoonoses Public Health, 60, 253-268. Vasan, A., Leong, W. M., Ingham, S. C. and Ingham, B. H. (2013) ‘Thermal tolerance characteristics of non-O157 Shiga toxigenic strains of Escherichia coli (STEC) in a beef broth model system are similar to those of O157::H7 STEC’, J. Food Prot., 76, 1120–1128. Wahl, E., Vold, L., Lindstedt, B. A., Brujheim, T., and Afset, J. E. (2011) ‘Investigation of an Escherichia coli O145 outbreak in a child day-care centre – extensive sampling and characterization of eae- and stx1-positive E. coli yields epidemiological and socioeconomic insight’, BMC Infect. Dis., 11, 238. Wang, F., Yang, Q., Kase, J. A., and Meng, J. (2013) ‘Current trends in detecting nonO157 Shiga toxin-producing Escherichia coli in food’ Foodborne Pathog. Dis., 10, 1–13. Wasilenko, J. L., Fratamico, P. M., Narang, N., Tillman, G. E., Ladely, S., Simmons, M., Cray, W. C., Jr, (2012) ‘Influence of primer sequences and DNA extraction method on detection of non-O157 Shiga toxin-producing Escherichia coli in ground beef by real-time PCR targeting the eae, stx, and serogroup-specific genes’ J. Food Prot., 75, 1939–1950. Werber, D., Fruth, A., Liesegang, A., Littmann, M., Buchholz, U., Prager, R., Karch, H., Breuer, T., Tschäpe, H., and Ammon, A. (2002) ‘A multistate outbreak of Shiga toxin-producing Escherichia coli O26:H11 infections in Germany, detected by molecular subtyping surveillance’, J. Infect. Dis., 186, 419–422. World Health Organization (2011), International Health Regulations, Outbreaks of E. coli O104:H4 infections: update 30. Available from: http://www.euro.who.int/ en/health-topics/emergencies/international-health-regulations/outbreaks-of-e.coli-o104h4-infection. Accessed 16 February 2014. Yan, X., Fratamico, P. M., Needleman, D. S., and Bayles, D. O. (2012) ‘DNA sequence and analysis of a 90.1-kb plasmid in Shiga toxin-producing Escherichia coli (STEC) O145:NM 83–75’, Plasmid, 68, 25–32. Zumbrun, S. D., Melton-Celsa, A. R., Smith, M. A., Gilbreath, J. J., Merrell, D. S., and O’Brien, A. D. (2013) ‘Dietary choice affects Shiga toxin-producing Escherichia coli (STEC) O157:H7 colonization and disease’, Proc. Natl. Acad. Sci. U S A, 110, E2126–2133.