- Email: [email protected]
Antimicrobial susceptibility of Aeromonas spp., Vibrio spp. and Plesiomonas shigelloides isolated in the Philippines and Thailand
348
Letters to the Editor / International Journal of Antimicrobial Agents 25 (2005) 345–353
M. Maniati 1 E. Petinaki 1 Kontos A.N. Maniatis ∗ a Department of Microbiology, School of Medicine University of Thessalia, Papakyriazi 22, Larissa, Greece b Department
I. Spiliopoulou of Microbiology, School of Medicine University of Patras, Greece
D. Petropoulou-Mylona H. Malamou-Lada c Department of Microbiology, General Hospital of Athens “G. Genimatas”, Athens L. Spaliara Ch. Koutsia-Carouzou d Department of Microbiology, General Hospital “Asclepeion”, Voula, Athens ∗ Corresponding
author. Tel.: +30 41 0682514 fax: +30 41 0682508 E-mail addresses: [email protected] (E. Petinaki) [email protected] (A.N. Maniatis) 1 These two authors contributed equally to this work
doi:10.1016/j.ijantimicag.2005.01.015
Antimicrobial susceptibility of Aeromonas spp., Vibrio spp. and Plesiomonas shigelloides isolated in the Philippines and Thailand Aeromonas spp., non-cholera vibrios (NCVs) and Plesiomonas shigelloides belong to the expanding group of water and food-borne pathogens. They are widely distributed in aquatic environments and are increasingly regarded as important pathogens of aquatic animals, causing significant economic losses in the aquaculture industry worldwide. In addition, these bacteria have been implicated as opportunistic pathogens, mainly causing gastroenteritis in humans [1]. The occurrence and isolation of these bacteria from different sources has been reported in Asia, including the Philippines and Thailand [2–4]. However, information on antimicrobial susceptibility of these isolates, especially those recovered from aquaculture and aquatic environments is scarce [5]. The aim of this study was to acquire data on the occurrence of antimicrobial resistance among 38 strains of Aeromonas spp., NCVs and P. shigelloides isolated from different sources in the Philippines and Thailand. In addition, the production of extended-spectrum -lactamases (ESBLs) by selected strains was determined. Thirty-eight strains belonging to Aeromonas spp. (n = 9), NCVs (n = 27) and P. shigelloides (n = 2) were used in the study. Six of the Aeromonas spp. were derived from human patients and one each from the Nile Tilapia, the spot-
ted Ghost Catfish and creek water. Twenty-one NCVs were from environmental sources and six from aquatic animals. The two isolates of P. shigelloides came from catfish. A broth microdilution method (VETMICTM , National Veterinary Institute (SVA), Uppsala, Sweden) was used for susceptibility testing. The standards of the National Committee for Clinical Laboratory Standards (NCCLS) M31-A were followed with some modifications [6]. The direct inoculum method, with Mueller–Hinton broth (MHB, Difco, MD, USA) as test medium, was used and the microdilution panels were incubated at 28 ◦ C for 18 h. Escherichia coli ATCC 25922 was included as a quality control strain; Aeromonas hydrophila ATCC 35654, and V. harveyi CCUG 28584 were included as reference strains. Minimum inhibitory concentration (MIC) was registered as the lowest concentration of an antimicrobial agent completely inhibiting bacterial growth. As no criteria were available for these bacteria, the Swedish Veterinary Antimicrobial Resistance Monitoring (SVARM 2002, SVA, Uppsala) susceptibility criterion for Enterobacteriaceae was used [7]. Strains resistant to ampicillin (n = 22) were tested for the presence of ESBLs by a combination disk diffusion method and susceptibility to imipenem used NCCLS standards M100-S9 with some modifications [8]. Mueller–Hinton agar (Oxoid, Hampshire, England) was used and the plates were incubated at 28 ◦ C for 18 h. The results for MIC determination and antimicrobial susceptibility are summarised in Table 1 . Eight of nine Aeromonas isolates (89%) were resistant to ampicillin, including seven strains of A. hydrophila and one strain of A. veronii bv sobria; these were all clinical strains. An environmental strain of A. hydrophila was susceptible to ampicillin. Of the NCVs, all Vibrio spp. (non-human, environmental) were susceptible to ampicillin, while 12 strains of V. parahaemolyticus and both strains of V. cholerae Non-O1 were susceptible. Five strains of A. hydrophila and one strain of A. veronii bv sobria were resistant to ceftiofur, whereas all strains of NCVs were susceptible. In the case of aminoglycosides (gentamicin, neomycin, streptomycin), florfenicol and TMPS all Aeromonas spp. and NCVs were susceptible. Two strains of A. hydrophila and one strain of A. veronii bv sobria were resistant to enrofloxacin; whereas four strains of A. hydrophila and one strain of A. veronii bv sobria were resistant to oxytetracycline. Both strains of P. shigelloides were resistant to ampicillin, neomycin and streptomycin; and one strain (no. 14) was resistant to enrofloxacin, oxytetracycline and TMPS. None of the ampicillin-resistant strains was an ESBL producer and all strains of Aeromonas, NCVs and P. shigelloides were susceptible to imipenem. Except for the observed resistance to ampicillin, antimicrobial resistance among the strains was rare in this study, especially for those strains that were recovered from the environment. Significant findings were observed among clinical strains that although previously reported as susceptible, now appear to be developing resistance. This is in the case of several A. hydrophila strains from
Letters to the Editor / International Journal of Antimicrobial Agents 25 (2005) 345–353
349
Table 1 Distribution of MICs for bacterial strains examined MIC (mg/L)
A. hydrophila
A. veronii bv sobria
Vibrio spp.a
V. parahaemolytiucs
V. cholerae Non-O1
P. shigelloides
Number
8
1
11
14
2
2
Ampicillin ≤1 2 4 8 >8
1 0 0 0 7
0 0 0 0 1
8 2 0 1 0
0 1 1 0 12
0 0 1 1 0
0 0 0 0 2
Ceftiofur ≤0.25 0.5 1 2 4 8 16 >16
0 1 1 1 0 1 1 3
0 0 0 0 0 0 0 1
4 7 0 0 0 0 0 0
1 3 9 1 0 0 0 0
0 0 0 2 0 0 0 0
0 0 0 1 1 0 0 0
Gentamicin ≤2 4 8 16 >16
7 1 0 0 0
1 0 0 0 0
11 0 0 0 0
8 6 0 0 0
2 0 0 0 0
0 0 2 0 0
Neomycin ≤4 8 16 32 >32
7 1 0 0 0
1 0 0 0 0
11 0 0 0 0
14 0 0 0 0
2 0 0 0 0
0 0 2 0 0
Streptomycin ≤4 8 16 32 >32
0 4 3 1 0
0 0 1 0 0
1 8 2 0 0
0 1 9 4 0
0 0 2 0 0
0 0 0 0 2b
Enrofloxacin ≤0.12 0.25 0.5 1 2 4 >4
6 0 0 1 0 0 1
0 0 0 1 0 0 0
9 2 0 0 0 0 0
1 12 1 0 0 0 0
2 0 0 0 0 0 0
1 0 0 0 0 0 1
Florfenicol ≤2 4 8 16 >16
7 1 0 0 0
1 0 0 0 0
11 0 0 0 0
14 0 0 0 0
2 0 0 0 0
2 0 0 0 0
Oxytetracycline ≤1 2 4 8 16 32 64
3 0 0 1c 0 2 2
0 0 0 0 0 1 0
11 0 0 0 0 0 0
14 0 0 0 0 0 0
2 0 0 0 0 0 0
1 0 0 0 0 0 1
350
Letters to the Editor / International Journal of Antimicrobial Agents 25 (2005) 345–353
Table 1 (Continued ) MIC (mg/L) >64 TMPS ≤0.5/9.5 1/19 2/38 4/76 >4/76
Vibrio spp.a
A. hydrophila
A. veronii bv sobria
0
0
0
7 1 0 0 0
1 0 0 0 0
10 1 0 0 0
V. parahaemolytiucs
V. cholerae Non-O1
P. shigelloides
0
0
0
14 0 0 0 0
2 0 0 0 0
0 0 1 1 0
Shaded areas indicate resistance. a Species that are pathogenic for humans were ruled out using 25 biochemical tests, which include the following species: V. cholerae, V. parahaemolyticus, V. vulnificus, V. mimicus, V. fluvialis, V. furnissii, V. (Grimontia) hollisae, V. (Listonella) damselae, V. alginolyticus, V. metschnikovii, V. cincinnatiensis, V. harveyi (V. charchariae). b ≥256. c >8.
R.P. Maluping a,b C.R. Lavilla-Pitogo c A. DePaola d J.M. Janda e K. Krovacek a,∗ C. Greko f
human diarrhoeic patients wherein acquired resistance to tetracycline and fluoroquinolone was demonstrated. It could be possible that this acquired resistance is associated with the use of antimicrobials in therapy.
Acknowledgements The Swedish Foundation for International Co-operation in Research and Higher Education (STINT) awarded R.P. Maluping with a scholarship. We thank Dr. Pongrama Ramasoota and Dr. Temdoung Somsiri for providing some of the strains.
a
Department of Biomedical Sciences and Veterinary Public Health, Faculty of Veterinary Medicine, SLU, Box 7036, SE-75007 Uppsala, Sweden b Department
of Veterinary Paraclinical Sciences, College of Veterinary Medicine, University of the Philippines-Los Banos, 4031 College, Laguna, Philippines c Aquaculture Department, Southeast Asian Fisheries Development Centre, Tigbauan, 5021 Iloilo, Philippines
References [1] Austin B, Austin DA. Bacterial fish pathogens. In: Disease in farmed and wild fish. Chichester, UK: Ellis Horwood; 1993. [2] Adkins HJ, Escamilla J, Santiago LT, Ranoa C, Echeverria P, Cross JH. Two-year survey of etiologic agents of diarrheal disease at San Lazaro Hospital, Manila Republic of the Philippines. J Clin Microbiol 1987;25:1143–7. [3] Haque QM, Sugiyama A, Iwade Y, et al. Characterization of Aeromonas hydrophila: a comparative study of strains isolated from diarrheal feces and the environment. Southeast Asian J Trop Med Pub Health 1996;27:132–8. [4] Pascual KC, Vizmanos MFC, Masangkay JS, Padilla MA, Albaladejo JD. Isolation of Vibrio spp. from shrimp disease epizootic in Panay Island, Philippines. Phil J Vet Med 1996;33:67–71. [5] Gr¨aslund S, Bengtsson B. Chemicals and biological products used in south-east Asian shrimp farming, and their potential impact on the environment—a review. Sci Total Environ 2001;280:93–131. [6] National Committee for Clinical Standards. Performance standards for antimicrobial disk and dilution susceptibility test for bacteria isolated from animals. Approved standard M31-A. Wayne, PA: National Committee for Clinical Laboratory Standards; 1999. [7] SVARM 2002. In: Bengtsson B, Greko C, Wall´en C, editors. Swedish veterinary antimicrobial resistance monitoring. Uppsala, Sweden: National Veterinary Institute. ISSN 1650-6332. [8] National Committee for Clinical Standards. Performance standards for antimicrobial susceptibility testing. Approved standard M100-S9. Wayne, PA: National Committee for Clinical Laboratory Standards; 1999.
d
Gulf Coast Seafood Laboratory, U.S. Food and Drug Administration (FDA), Dauphin Island AL 36528-0158, USA
e Microbial
Diseases Laboratory, California Department of Health, 850 Marina Bay Parkway, Room E164, Richmond, CA 94804, USA f
Department of Antibiotics, National Veterinary Institute (SVA), SE-75189 Uppsala, Sweden ∗ Corresponding
author. Tel.: +46 18 673191 fax: +46 18 504461 E-mail address: [email protected] (K. Krovacek)
doi:10.1016/j.ijantimicag.2005.01.003
Emergence of CTX-M-type -lactam resistance in Shigella spp. in Hong Kong Sir, In Hong Kong, the Public Health Laboratory Services Branch (PHLSB) under Centre for Health Protection
Letters to the Editor / International Journal of Antimicrobial Agents 25 (2005) 345–353
M. Maniati 1 E. Petinaki 1 Kontos A.N. Maniatis ∗ a Department of Microbiology, School of Medicine University of Thessalia, Papakyriazi 22, Larissa, Greece b Department
I. Spiliopoulou of Microbiology, School of Medicine University of Patras, Greece
D. Petropoulou-Mylona H. Malamou-Lada c Department of Microbiology, General Hospital of Athens “G. Genimatas”, Athens L. Spaliara Ch. Koutsia-Carouzou d Department of Microbiology, General Hospital “Asclepeion”, Voula, Athens ∗ Corresponding
author. Tel.: +30 41 0682514 fax: +30 41 0682508 E-mail addresses: [email protected] (E. Petinaki) [email protected] (A.N. Maniatis) 1 These two authors contributed equally to this work
doi:10.1016/j.ijantimicag.2005.01.015
Antimicrobial susceptibility of Aeromonas spp., Vibrio spp. and Plesiomonas shigelloides isolated in the Philippines and Thailand Aeromonas spp., non-cholera vibrios (NCVs) and Plesiomonas shigelloides belong to the expanding group of water and food-borne pathogens. They are widely distributed in aquatic environments and are increasingly regarded as important pathogens of aquatic animals, causing significant economic losses in the aquaculture industry worldwide. In addition, these bacteria have been implicated as opportunistic pathogens, mainly causing gastroenteritis in humans [1]. The occurrence and isolation of these bacteria from different sources has been reported in Asia, including the Philippines and Thailand [2–4]. However, information on antimicrobial susceptibility of these isolates, especially those recovered from aquaculture and aquatic environments is scarce [5]. The aim of this study was to acquire data on the occurrence of antimicrobial resistance among 38 strains of Aeromonas spp., NCVs and P. shigelloides isolated from different sources in the Philippines and Thailand. In addition, the production of extended-spectrum -lactamases (ESBLs) by selected strains was determined. Thirty-eight strains belonging to Aeromonas spp. (n = 9), NCVs (n = 27) and P. shigelloides (n = 2) were used in the study. Six of the Aeromonas spp. were derived from human patients and one each from the Nile Tilapia, the spot-
ted Ghost Catfish and creek water. Twenty-one NCVs were from environmental sources and six from aquatic animals. The two isolates of P. shigelloides came from catfish. A broth microdilution method (VETMICTM , National Veterinary Institute (SVA), Uppsala, Sweden) was used for susceptibility testing. The standards of the National Committee for Clinical Laboratory Standards (NCCLS) M31-A were followed with some modifications [6]. The direct inoculum method, with Mueller–Hinton broth (MHB, Difco, MD, USA) as test medium, was used and the microdilution panels were incubated at 28 ◦ C for 18 h. Escherichia coli ATCC 25922 was included as a quality control strain; Aeromonas hydrophila ATCC 35654, and V. harveyi CCUG 28584 were included as reference strains. Minimum inhibitory concentration (MIC) was registered as the lowest concentration of an antimicrobial agent completely inhibiting bacterial growth. As no criteria were available for these bacteria, the Swedish Veterinary Antimicrobial Resistance Monitoring (SVARM 2002, SVA, Uppsala) susceptibility criterion for Enterobacteriaceae was used [7]. Strains resistant to ampicillin (n = 22) were tested for the presence of ESBLs by a combination disk diffusion method and susceptibility to imipenem used NCCLS standards M100-S9 with some modifications [8]. Mueller–Hinton agar (Oxoid, Hampshire, England) was used and the plates were incubated at 28 ◦ C for 18 h. The results for MIC determination and antimicrobial susceptibility are summarised in Table 1 . Eight of nine Aeromonas isolates (89%) were resistant to ampicillin, including seven strains of A. hydrophila and one strain of A. veronii bv sobria; these were all clinical strains. An environmental strain of A. hydrophila was susceptible to ampicillin. Of the NCVs, all Vibrio spp. (non-human, environmental) were susceptible to ampicillin, while 12 strains of V. parahaemolyticus and both strains of V. cholerae Non-O1 were susceptible. Five strains of A. hydrophila and one strain of A. veronii bv sobria were resistant to ceftiofur, whereas all strains of NCVs were susceptible. In the case of aminoglycosides (gentamicin, neomycin, streptomycin), florfenicol and TMPS all Aeromonas spp. and NCVs were susceptible. Two strains of A. hydrophila and one strain of A. veronii bv sobria were resistant to enrofloxacin; whereas four strains of A. hydrophila and one strain of A. veronii bv sobria were resistant to oxytetracycline. Both strains of P. shigelloides were resistant to ampicillin, neomycin and streptomycin; and one strain (no. 14) was resistant to enrofloxacin, oxytetracycline and TMPS. None of the ampicillin-resistant strains was an ESBL producer and all strains of Aeromonas, NCVs and P. shigelloides were susceptible to imipenem. Except for the observed resistance to ampicillin, antimicrobial resistance among the strains was rare in this study, especially for those strains that were recovered from the environment. Significant findings were observed among clinical strains that although previously reported as susceptible, now appear to be developing resistance. This is in the case of several A. hydrophila strains from
Letters to the Editor / International Journal of Antimicrobial Agents 25 (2005) 345–353
349
Table 1 Distribution of MICs for bacterial strains examined MIC (mg/L)
A. hydrophila
A. veronii bv sobria
Vibrio spp.a
V. parahaemolytiucs
V. cholerae Non-O1
P. shigelloides
Number
8
1
11
14
2
2
Ampicillin ≤1 2 4 8 >8
1 0 0 0 7
0 0 0 0 1
8 2 0 1 0
0 1 1 0 12
0 0 1 1 0
0 0 0 0 2
Ceftiofur ≤0.25 0.5 1 2 4 8 16 >16
0 1 1 1 0 1 1 3
0 0 0 0 0 0 0 1
4 7 0 0 0 0 0 0
1 3 9 1 0 0 0 0
0 0 0 2 0 0 0 0
0 0 0 1 1 0 0 0
Gentamicin ≤2 4 8 16 >16
7 1 0 0 0
1 0 0 0 0
11 0 0 0 0
8 6 0 0 0
2 0 0 0 0
0 0 2 0 0
Neomycin ≤4 8 16 32 >32
7 1 0 0 0
1 0 0 0 0
11 0 0 0 0
14 0 0 0 0
2 0 0 0 0
0 0 2 0 0
Streptomycin ≤4 8 16 32 >32
0 4 3 1 0
0 0 1 0 0
1 8 2 0 0
0 1 9 4 0
0 0 2 0 0
0 0 0 0 2b
Enrofloxacin ≤0.12 0.25 0.5 1 2 4 >4
6 0 0 1 0 0 1
0 0 0 1 0 0 0
9 2 0 0 0 0 0
1 12 1 0 0 0 0
2 0 0 0 0 0 0
1 0 0 0 0 0 1
Florfenicol ≤2 4 8 16 >16
7 1 0 0 0
1 0 0 0 0
11 0 0 0 0
14 0 0 0 0
2 0 0 0 0
2 0 0 0 0
Oxytetracycline ≤1 2 4 8 16 32 64
3 0 0 1c 0 2 2
0 0 0 0 0 1 0
11 0 0 0 0 0 0
14 0 0 0 0 0 0
2 0 0 0 0 0 0
1 0 0 0 0 0 1
350
Letters to the Editor / International Journal of Antimicrobial Agents 25 (2005) 345–353
Table 1 (Continued ) MIC (mg/L) >64 TMPS ≤0.5/9.5 1/19 2/38 4/76 >4/76
Vibrio spp.a
A. hydrophila
A. veronii bv sobria
0
0
0
7 1 0 0 0
1 0 0 0 0
10 1 0 0 0
V. parahaemolytiucs
V. cholerae Non-O1
P. shigelloides
0
0
0
14 0 0 0 0
2 0 0 0 0
0 0 1 1 0
Shaded areas indicate resistance. a Species that are pathogenic for humans were ruled out using 25 biochemical tests, which include the following species: V. cholerae, V. parahaemolyticus, V. vulnificus, V. mimicus, V. fluvialis, V. furnissii, V. (Grimontia) hollisae, V. (Listonella) damselae, V. alginolyticus, V. metschnikovii, V. cincinnatiensis, V. harveyi (V. charchariae). b ≥256. c >8.
R.P. Maluping a,b C.R. Lavilla-Pitogo c A. DePaola d J.M. Janda e K. Krovacek a,∗ C. Greko f
human diarrhoeic patients wherein acquired resistance to tetracycline and fluoroquinolone was demonstrated. It could be possible that this acquired resistance is associated with the use of antimicrobials in therapy.
Acknowledgements The Swedish Foundation for International Co-operation in Research and Higher Education (STINT) awarded R.P. Maluping with a scholarship. We thank Dr. Pongrama Ramasoota and Dr. Temdoung Somsiri for providing some of the strains.
a
Department of Biomedical Sciences and Veterinary Public Health, Faculty of Veterinary Medicine, SLU, Box 7036, SE-75007 Uppsala, Sweden b Department
of Veterinary Paraclinical Sciences, College of Veterinary Medicine, University of the Philippines-Los Banos, 4031 College, Laguna, Philippines c Aquaculture Department, Southeast Asian Fisheries Development Centre, Tigbauan, 5021 Iloilo, Philippines
References [1] Austin B, Austin DA. Bacterial fish pathogens. In: Disease in farmed and wild fish. Chichester, UK: Ellis Horwood; 1993. [2] Adkins HJ, Escamilla J, Santiago LT, Ranoa C, Echeverria P, Cross JH. Two-year survey of etiologic agents of diarrheal disease at San Lazaro Hospital, Manila Republic of the Philippines. J Clin Microbiol 1987;25:1143–7. [3] Haque QM, Sugiyama A, Iwade Y, et al. Characterization of Aeromonas hydrophila: a comparative study of strains isolated from diarrheal feces and the environment. Southeast Asian J Trop Med Pub Health 1996;27:132–8. [4] Pascual KC, Vizmanos MFC, Masangkay JS, Padilla MA, Albaladejo JD. Isolation of Vibrio spp. from shrimp disease epizootic in Panay Island, Philippines. Phil J Vet Med 1996;33:67–71. [5] Gr¨aslund S, Bengtsson B. Chemicals and biological products used in south-east Asian shrimp farming, and their potential impact on the environment—a review. Sci Total Environ 2001;280:93–131. [6] National Committee for Clinical Standards. Performance standards for antimicrobial disk and dilution susceptibility test for bacteria isolated from animals. Approved standard M31-A. Wayne, PA: National Committee for Clinical Laboratory Standards; 1999. [7] SVARM 2002. In: Bengtsson B, Greko C, Wall´en C, editors. Swedish veterinary antimicrobial resistance monitoring. Uppsala, Sweden: National Veterinary Institute. ISSN 1650-6332. [8] National Committee for Clinical Standards. Performance standards for antimicrobial susceptibility testing. Approved standard M100-S9. Wayne, PA: National Committee for Clinical Laboratory Standards; 1999.
d
Gulf Coast Seafood Laboratory, U.S. Food and Drug Administration (FDA), Dauphin Island AL 36528-0158, USA
e Microbial
Diseases Laboratory, California Department of Health, 850 Marina Bay Parkway, Room E164, Richmond, CA 94804, USA f
Department of Antibiotics, National Veterinary Institute (SVA), SE-75189 Uppsala, Sweden ∗ Corresponding
author. Tel.: +46 18 673191 fax: +46 18 504461 E-mail address: [email protected] (K. Krovacek)
doi:10.1016/j.ijantimicag.2005.01.003
Emergence of CTX-M-type -lactam resistance in Shigella spp. in Hong Kong Sir, In Hong Kong, the Public Health Laboratory Services Branch (PHLSB) under Centre for Health Protection