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Primary pyogenic liver abscess caused by magA+ Klebsiella pneumoniae in Spain
Case Report
Primary Pyogenic Liver Abscess Caused by magA+ Klebsiella pneumoniae in Spain Carmen Gomez, M.S., Amparo Broseta, M.S., Joaquín R. Otero, M.D., and Fernando Chaves, M.D., Servicio de Microbiología, Hospital Doce de Octubre, Madrid 28041, Spain
Introduction Klebsiella pneumoniae is an important opportunistic pathogen in humans. Klebsiella spp. are ubiquitous in nature, with two common habitats, one being the environment and the other being the mucosal surfaces of mammals. In humans, K. pneumoniae is present as a saprophyte in the intestinal tract and nasopharynx (1). This enteric gramnegative bacillus is a common nosoco-
Mailing Address: Dr Fernando Chaves, Servicio de Microbiología, Hospital Doce de Octubre, Avenida de Cordoba sn, Madrid 28041, Spain. Tel.: (34) 913908239. Fax: (34) 915652765. E-mail: [email protected].
100
0196-4399/00 (see frontmatter)
mial pathogen, causing pneumonia and soft tissue, intra-abdominal, and urinary tract infections. This microorganism is also a potential community-acquired pathogen.
Case Report A 61-year-old Spanish male presented to the emergency room (ER) with a 6-day history of fever, chills, abdominal pain, anorexia, malaise, and a dry cough. During the previous weeks, he had experienced occasional pain in the upper right quadrant of his abdomen. His medical record indicated a history of heavy smoking, alcohol abuse, hypercholesterolemia, colonic diverticulosis, and prostate cancer with multiple bone metastases treated with © 2007 Elsevier
hormonal therapy. He denied any significant travel history. Five years prior to this visit, he had been diagnosed with a right-lobe liver abscess with bacteremia due to K. pneumoniae, and he was treated only with antibiotics. A physical examination in our ER revealed mild tenderness in the upper right quadrant and a liver edge that was palpable 3 cm below the right costal margin. Laboratory values were normal except for a total bilirubin of 3.1 mg/dl, alkaline phosphatase of 894 IU/L, alanine aminotransferase of 97 IU/L, and aspartate aminotransferase of 108 IU/L. Serologic tests for hepatitis viruses B and C and Entamoeba histolytica were negative. An abdominal ultrasound, followed by computerized tomography Clinical Microbiology Newsletter 29:13,2007
scanning, showed a 10 x 7 x 6.5-cm multiloculated abscess in the right hepatic lobe. The patient was treated empirically with intravenous piperacillin/ tazobactam. On day 1 of hospitalization, blood cultures from admission grew gram-negative rods that were later identified as K. pneumoniae. The patient’s fever persisted, and 7 days later, computed tomography (CT)-guided drainage of the abscess yielded purulent material that grew K. pneumoniae. Both clinical isolates were susceptible to all antimicrobial agents tested, except for ampicillin, and they had a hyperviscous phenotype, characterized by the formation of elongated (>5 mm) mucoviscous strings when a loop was passed through a colony. Antimicrobial treatment was switched to intravenous ceftriaxone and oral ciprofloxacin for 3 weeks. Clinically, the patient improved and was given an additional 4-week course of oral ciprofloxacin. A follow-up CT scan after antibiotic therapy showed abscess resolution.
Discussion Over the past 25 years, a new type of invasive K. pneumoniae disease, which typically appears as a communityacquired primary liver abscess with bacteremia, has emerged in Taiwan (2,3). This syndrome has been described mainly in Asian countries, where nearly 1,000 cases of Klebsiella liver abscesses (KLA) have been reported (4). KLA occur mainly in diabetic patients without intra-abdominal or biliary tract infection. The development of metastatic infections, a rare complication of gram-negative septicemia, is a characteristic feature of KLA. Approximately 10 to 12% of reported cases developed metastatic meningitis or endophthalmitis and metastatic infections in other anatomic sites (2). Capsular serotyping of K. pneumoniae isolates from KLA in Taiwan demonstrated that serotype K1 was significantly associated with liver abscesses and the complication of endophthalmitis (3). Ribotyping in these isolates identified different degrees of genetic polymorphism among isolates with the same K1 serotype, indicating no particular prevalence of any one strain in KLA. A recent report from Taiwan has demonstrated a novel virulence gene, magA, in K. pneumoniae strains causing Clinical Microbiology Newsletter 29:13,2007
pyogenic liver abscesses (5). The magA gene (mucoviscosity-associated gene A) was associated with the hypermucoviscosity phenotype and was detected in the majority of K. pneumoniae strains causing primary liver abscess and septic metastatic complications. This gene is a component of capsule formation and is specific for K. pneumoniae serotype K1 (6-8). Using primer pairs derived from the magA gene, PCR is a rapid and accurate method to detect K1 strains. Microorganisms with the magA gene were highly resistant to killing by human serum and phagocytosis. A recent report, which studied the genomic variations between tissue-invasive strains and non-invasive strains of K. pneumoniae, found that strains from patients with KLA plus endophthalmitis or meningitis contained all three specific DNA regions, including the magA region (9). These authors proposed that K. pneumoniae gains entry into the bloodstream via the gastrointestinal tract. Bacteria containing these genomic regions would have an increased ability to invade tissue because of its enhanced survival and ability to compete for nutrients. Although many bacteria would likely be trapped in the liver by Kupffer cells, these invasive strains would be resistant to phagocytosis by polymorphonuclear leukocytes and serum killing, which could result in the subsequent formation of liver abscesses. Because of the hypermucoviscous colony characteristic of the K. pneumoniae strain isolated from the liver abscess and blood of our patient and the similarity of the Spanish case to the clinical presentation of the cases reported in Taiwan, we examined these isolates for the presence of the magA gene. The presence of this gene in Spanish isolates had not yet been assessed. Genomic DNA was extracted from our two clinical isolates and two isolates (one from urine and the other from sputum) from unrelated patients. Unfortunately, the clinical isolate that was obtained from a blood sample 5 years prior to this episode was not available for further studies. A 540-bp fragment was amplified by PCR with the primers magA-F (5'-CGC-CGC-AAA-TAC-GAG-AAGTG-3') and magA-R (5'-GCA-ATCGAA-GTG-AAG-AGT-GC-3') (10). Fragments were detected by electro© 2007 Elsevier
phoresis through 1.5% agarose. The two clinical isolates from the liver abscess case contained the magA gene. The amplified products were sequenced for confirmation by using the BigDye Terminator v3.1 Cycle Sequencing Kit and an ABI Prism 3100 Avant genetic analyzer (Applied Biosystems, Foster City, CA). The sequences of the isolates (GenBank accession no. DQ677561) were compared to all bacterial sequences available from the GenBank database by using the BLAST program (http:// www.ncbi.nlm.nih.gov/BLAST/BLAST .cgi) and showed 100% similarity to the sequences of the magA gene of K. pneumoniae (GenBank accession no. AY762939, AB198423, AB117611, and AB085741). To further investigate the prevalence of the magA gene in the cases of K. pneumoniae bacteremia, we studied a collection of 45 clinical isolates obtained from blood during an 18-month period (January 2004 to June 2005) in our hospital. Analysis by realtime PCR did not yield positive results, with the exception of the blood sample from our clinical case. This represents the first reported clinical case of a magA+ K. pneumoniae strain associated with liver abscess and bacteremia in Spain. At this time, we believe that these strains are still rare in our country. We do not know the origin of these strains in Spain or whether the strains may have been present previously in the country (11). Some clinical cases of KLA have been reported recently in Western countries, affecting patients originating from Asian countries and patients born in Western countries without a recent travel history to Asian countries (12,13). In Taiwan, KLA and the septic metastatic complications have emerged as one of the most common community-acquired bacterial diseases, and K. pneumoniae has replaced Streptococcus pneumoniae as the leading cause of adult community-acquired bacterial meningitis (5). The reason for this rapid increase of primary KLA remains unclear. A survey performed 2 decades ago showed a small number of K1 serotypes of K. pneumoniae to be associated with bacteremia in Europe (14). Further large-scale studies of the serotype prevalence of K. pneumoniae in Spain may be necessary. The increase in the number of reported cases of KLA in non-Asian 0196-4399/00 (see frontmatter)
101
countries (12,13) that involve patients of Asian descent and the autochthonous population of those countries suggests that KLA may represent a significant and emerging infectious disease in Western countries. Rapid identification of the virulent K1 serotype, and/or detection of the magA gene by PCR analysis, will be very useful in diagnosis and treatment of severe infections and in epidemiological studies.
5.
6.
References 1. Podschun, R. and U. Ullmann. 1998. Klebsiella spp. as nosocomial pathogens: epidemiology, taxonomy, typing methods, and pathogenicity factors. Clin. Microbiol. Rev. 11:589-603. 2. Wang, J.H. et al. 1998. Primary liver abscess due to Klebsiella pneumoniae in Taiwan. Clin. Infect. Dis. 26:1434-1438.
7.
8.
3. Fung, C.P. et al. 2002. A global emerging disease of Klebsiella pneumoniae liver abscess: is serotype K1 an important factor for complicated endophthalmitis? Gut 50:420-424. 4. Ko, W.C. et al. 2002. Community-
102
0196-4399/00 (see frontmatter)
9.
acquired Klebsiella pneumoniae bacteremia: global differences in clinical patterns. Emerg. Infect. Dis. 8:160-166. Fang, C.T. et al. 2004. A novel virulence gene in Klebsiella pneumoniae strains causing primary liver abscess and septic metastatic complications. J. Exp. Med. 199:697-705. Struve, C. et al. 2005. Investigation of the putative virulence gene magA in a worldwide collection of 495 Klebsiella isolates: magA is restricted to the gene cluster of Klebsiella pneumoniae capsule serotype K1. J. Med. Microbiol. 54:1111-1113. Chuang, Y.P. et al. 2006. Genetic determinants of capsular serotype K1 of Klebsiella pneumoniae causing primary pyogenic liver abscess. J. Infect. Dis. 193:645-654. Yeh, K.M. et al. 2006. magA is not a specific virulence gene for Klebsiella pneumoniae strains causing liver abscess but is part of the capsular polysaccharide gene cluster of K. pneumoniae serotype K1. J. Med. Microbiol. 55:803-804. Ma, L.C. et al. 2005. Genomic hetero-
© 2007 Elsevier
geneity in Klebsiella pneumoniae strains is associated with primary pyogenic liver abscess and metastatic infection. J. Infect. Dis. 192:117-128. 10. Fang, F.C., N. Sandler, and S.J. Libby. 2005. Liver abscess caused by magA+ Klebsiella pneumoniae in North America. J. Clin. Microbiol. 43:991992. 11. Casanova, C. et al. 1989. Klebsiella pneumoniae liver abscess associated with septic endophthalmitis. Arch. Intern. Med. 149:1467. 12. Lederman, E.R. and N.F. Crum. 2005. Pyogenic liver abscess with a focus on Klebsiella pneumoniae as a primary pathogen: an emerging disease with unique clinical characteristics. Am. J. Gastroenterol. 100:322-331. 13. Rahimian, J. et al. 2004. Pyogenic liver abscess: recent trends in etiology and mortality. Clin. Infect. Dis. 39:16541659. 14. Cryz, S.J. et al. 1986. Seroepidemiology of Klebsiella bacteremic isolates and implications for vaccine development. J. Clin. Microbiol. 23:687-690.
Clinical Microbiology Newsletter 29:13,2007
Primary Pyogenic Liver Abscess Caused by magA+ Klebsiella pneumoniae in Spain Carmen Gomez, M.S., Amparo Broseta, M.S., Joaquín R. Otero, M.D., and Fernando Chaves, M.D., Servicio de Microbiología, Hospital Doce de Octubre, Madrid 28041, Spain
Introduction Klebsiella pneumoniae is an important opportunistic pathogen in humans. Klebsiella spp. are ubiquitous in nature, with two common habitats, one being the environment and the other being the mucosal surfaces of mammals. In humans, K. pneumoniae is present as a saprophyte in the intestinal tract and nasopharynx (1). This enteric gramnegative bacillus is a common nosoco-
Mailing Address: Dr Fernando Chaves, Servicio de Microbiología, Hospital Doce de Octubre, Avenida de Cordoba sn, Madrid 28041, Spain. Tel.: (34) 913908239. Fax: (34) 915652765. E-mail: [email protected].
100
0196-4399/00 (see frontmatter)
mial pathogen, causing pneumonia and soft tissue, intra-abdominal, and urinary tract infections. This microorganism is also a potential community-acquired pathogen.
Case Report A 61-year-old Spanish male presented to the emergency room (ER) with a 6-day history of fever, chills, abdominal pain, anorexia, malaise, and a dry cough. During the previous weeks, he had experienced occasional pain in the upper right quadrant of his abdomen. His medical record indicated a history of heavy smoking, alcohol abuse, hypercholesterolemia, colonic diverticulosis, and prostate cancer with multiple bone metastases treated with © 2007 Elsevier
hormonal therapy. He denied any significant travel history. Five years prior to this visit, he had been diagnosed with a right-lobe liver abscess with bacteremia due to K. pneumoniae, and he was treated only with antibiotics. A physical examination in our ER revealed mild tenderness in the upper right quadrant and a liver edge that was palpable 3 cm below the right costal margin. Laboratory values were normal except for a total bilirubin of 3.1 mg/dl, alkaline phosphatase of 894 IU/L, alanine aminotransferase of 97 IU/L, and aspartate aminotransferase of 108 IU/L. Serologic tests for hepatitis viruses B and C and Entamoeba histolytica were negative. An abdominal ultrasound, followed by computerized tomography Clinical Microbiology Newsletter 29:13,2007
scanning, showed a 10 x 7 x 6.5-cm multiloculated abscess in the right hepatic lobe. The patient was treated empirically with intravenous piperacillin/ tazobactam. On day 1 of hospitalization, blood cultures from admission grew gram-negative rods that were later identified as K. pneumoniae. The patient’s fever persisted, and 7 days later, computed tomography (CT)-guided drainage of the abscess yielded purulent material that grew K. pneumoniae. Both clinical isolates were susceptible to all antimicrobial agents tested, except for ampicillin, and they had a hyperviscous phenotype, characterized by the formation of elongated (>5 mm) mucoviscous strings when a loop was passed through a colony. Antimicrobial treatment was switched to intravenous ceftriaxone and oral ciprofloxacin for 3 weeks. Clinically, the patient improved and was given an additional 4-week course of oral ciprofloxacin. A follow-up CT scan after antibiotic therapy showed abscess resolution.
Discussion Over the past 25 years, a new type of invasive K. pneumoniae disease, which typically appears as a communityacquired primary liver abscess with bacteremia, has emerged in Taiwan (2,3). This syndrome has been described mainly in Asian countries, where nearly 1,000 cases of Klebsiella liver abscesses (KLA) have been reported (4). KLA occur mainly in diabetic patients without intra-abdominal or biliary tract infection. The development of metastatic infections, a rare complication of gram-negative septicemia, is a characteristic feature of KLA. Approximately 10 to 12% of reported cases developed metastatic meningitis or endophthalmitis and metastatic infections in other anatomic sites (2). Capsular serotyping of K. pneumoniae isolates from KLA in Taiwan demonstrated that serotype K1 was significantly associated with liver abscesses and the complication of endophthalmitis (3). Ribotyping in these isolates identified different degrees of genetic polymorphism among isolates with the same K1 serotype, indicating no particular prevalence of any one strain in KLA. A recent report from Taiwan has demonstrated a novel virulence gene, magA, in K. pneumoniae strains causing Clinical Microbiology Newsletter 29:13,2007
pyogenic liver abscesses (5). The magA gene (mucoviscosity-associated gene A) was associated with the hypermucoviscosity phenotype and was detected in the majority of K. pneumoniae strains causing primary liver abscess and septic metastatic complications. This gene is a component of capsule formation and is specific for K. pneumoniae serotype K1 (6-8). Using primer pairs derived from the magA gene, PCR is a rapid and accurate method to detect K1 strains. Microorganisms with the magA gene were highly resistant to killing by human serum and phagocytosis. A recent report, which studied the genomic variations between tissue-invasive strains and non-invasive strains of K. pneumoniae, found that strains from patients with KLA plus endophthalmitis or meningitis contained all three specific DNA regions, including the magA region (9). These authors proposed that K. pneumoniae gains entry into the bloodstream via the gastrointestinal tract. Bacteria containing these genomic regions would have an increased ability to invade tissue because of its enhanced survival and ability to compete for nutrients. Although many bacteria would likely be trapped in the liver by Kupffer cells, these invasive strains would be resistant to phagocytosis by polymorphonuclear leukocytes and serum killing, which could result in the subsequent formation of liver abscesses. Because of the hypermucoviscous colony characteristic of the K. pneumoniae strain isolated from the liver abscess and blood of our patient and the similarity of the Spanish case to the clinical presentation of the cases reported in Taiwan, we examined these isolates for the presence of the magA gene. The presence of this gene in Spanish isolates had not yet been assessed. Genomic DNA was extracted from our two clinical isolates and two isolates (one from urine and the other from sputum) from unrelated patients. Unfortunately, the clinical isolate that was obtained from a blood sample 5 years prior to this episode was not available for further studies. A 540-bp fragment was amplified by PCR with the primers magA-F (5'-CGC-CGC-AAA-TAC-GAG-AAGTG-3') and magA-R (5'-GCA-ATCGAA-GTG-AAG-AGT-GC-3') (10). Fragments were detected by electro© 2007 Elsevier
phoresis through 1.5% agarose. The two clinical isolates from the liver abscess case contained the magA gene. The amplified products were sequenced for confirmation by using the BigDye Terminator v3.1 Cycle Sequencing Kit and an ABI Prism 3100 Avant genetic analyzer (Applied Biosystems, Foster City, CA). The sequences of the isolates (GenBank accession no. DQ677561) were compared to all bacterial sequences available from the GenBank database by using the BLAST program (http:// www.ncbi.nlm.nih.gov/BLAST/BLAST .cgi) and showed 100% similarity to the sequences of the magA gene of K. pneumoniae (GenBank accession no. AY762939, AB198423, AB117611, and AB085741). To further investigate the prevalence of the magA gene in the cases of K. pneumoniae bacteremia, we studied a collection of 45 clinical isolates obtained from blood during an 18-month period (January 2004 to June 2005) in our hospital. Analysis by realtime PCR did not yield positive results, with the exception of the blood sample from our clinical case. This represents the first reported clinical case of a magA+ K. pneumoniae strain associated with liver abscess and bacteremia in Spain. At this time, we believe that these strains are still rare in our country. We do not know the origin of these strains in Spain or whether the strains may have been present previously in the country (11). Some clinical cases of KLA have been reported recently in Western countries, affecting patients originating from Asian countries and patients born in Western countries without a recent travel history to Asian countries (12,13). In Taiwan, KLA and the septic metastatic complications have emerged as one of the most common community-acquired bacterial diseases, and K. pneumoniae has replaced Streptococcus pneumoniae as the leading cause of adult community-acquired bacterial meningitis (5). The reason for this rapid increase of primary KLA remains unclear. A survey performed 2 decades ago showed a small number of K1 serotypes of K. pneumoniae to be associated with bacteremia in Europe (14). Further large-scale studies of the serotype prevalence of K. pneumoniae in Spain may be necessary. The increase in the number of reported cases of KLA in non-Asian 0196-4399/00 (see frontmatter)
101
countries (12,13) that involve patients of Asian descent and the autochthonous population of those countries suggests that KLA may represent a significant and emerging infectious disease in Western countries. Rapid identification of the virulent K1 serotype, and/or detection of the magA gene by PCR analysis, will be very useful in diagnosis and treatment of severe infections and in epidemiological studies.
5.
6.
References 1. Podschun, R. and U. Ullmann. 1998. Klebsiella spp. as nosocomial pathogens: epidemiology, taxonomy, typing methods, and pathogenicity factors. Clin. Microbiol. Rev. 11:589-603. 2. Wang, J.H. et al. 1998. Primary liver abscess due to Klebsiella pneumoniae in Taiwan. Clin. Infect. Dis. 26:1434-1438.
7.
8.
3. Fung, C.P. et al. 2002. A global emerging disease of Klebsiella pneumoniae liver abscess: is serotype K1 an important factor for complicated endophthalmitis? Gut 50:420-424. 4. Ko, W.C. et al. 2002. Community-
102
0196-4399/00 (see frontmatter)
9.
acquired Klebsiella pneumoniae bacteremia: global differences in clinical patterns. Emerg. Infect. Dis. 8:160-166. Fang, C.T. et al. 2004. A novel virulence gene in Klebsiella pneumoniae strains causing primary liver abscess and septic metastatic complications. J. Exp. Med. 199:697-705. Struve, C. et al. 2005. Investigation of the putative virulence gene magA in a worldwide collection of 495 Klebsiella isolates: magA is restricted to the gene cluster of Klebsiella pneumoniae capsule serotype K1. J. Med. Microbiol. 54:1111-1113. Chuang, Y.P. et al. 2006. Genetic determinants of capsular serotype K1 of Klebsiella pneumoniae causing primary pyogenic liver abscess. J. Infect. Dis. 193:645-654. Yeh, K.M. et al. 2006. magA is not a specific virulence gene for Klebsiella pneumoniae strains causing liver abscess but is part of the capsular polysaccharide gene cluster of K. pneumoniae serotype K1. J. Med. Microbiol. 55:803-804. Ma, L.C. et al. 2005. Genomic hetero-
© 2007 Elsevier
geneity in Klebsiella pneumoniae strains is associated with primary pyogenic liver abscess and metastatic infection. J. Infect. Dis. 192:117-128. 10. Fang, F.C., N. Sandler, and S.J. Libby. 2005. Liver abscess caused by magA+ Klebsiella pneumoniae in North America. J. Clin. Microbiol. 43:991992. 11. Casanova, C. et al. 1989. Klebsiella pneumoniae liver abscess associated with septic endophthalmitis. Arch. Intern. Med. 149:1467. 12. Lederman, E.R. and N.F. Crum. 2005. Pyogenic liver abscess with a focus on Klebsiella pneumoniae as a primary pathogen: an emerging disease with unique clinical characteristics. Am. J. Gastroenterol. 100:322-331. 13. Rahimian, J. et al. 2004. Pyogenic liver abscess: recent trends in etiology and mortality. Clin. Infect. Dis. 39:16541659. 14. Cryz, S.J. et al. 1986. Seroepidemiology of Klebsiella bacteremic isolates and implications for vaccine development. J. Clin. Microbiol. 23:687-690.
Clinical Microbiology Newsletter 29:13,2007