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The need to differentiate Campylobacter fetus subspecies isolated from humans
CORRESPONDENCE
The need to differentiate Campylobacter fetus subspecies isolated from humans The recent review in Clinical Microbiology and Infection by Butzler [1] described how collaboration between medical doctors and their veterinary colleagues during the 1970s led to the discovery of Campylobacter enteritis. Nowadays, Campylobacter spp. are a leading cause of foodborne illness in the industrialised world. Campylobacter jejuni and Campylobacter coli are the most frequent species isolated from humans. However, the public health burden of other Campylobacter spp., such as Campylobacter fetus, remains unmeasured [1]. C. fetus is thought to be an underdiagnosed cause of human disease because of its fastidious requirements for growth media and incubation atmosphere. In particular, selective media used routinely for the isolation of Campylobacter spp. contain antibiotics such as cephalothin and cefoperazone, to which C. fetus can be susceptible [2]. The species C. fetus is divided into subspecies fetus (Cff) and venerealis (Cfv) on the basis of their biochemical differences [3]. Cff is recovered commonly from the gastrointestinal tract of animals, including food-producing animals, but has also been isolated occasionally from local and systemic infections in humans [4]. In contrast, Cfv appears to be adapted to the bovine genital tract, where it causes bovine genital campylobacteriosis. There are only seven reported cases of its isolation from human patients: from the stools of two homosexual men; from two women with bacterial vaginosis; and from blood and other, non-defined, samples from three patients [4–7]. The only accepted phenotypic method for subspeciation in routine laboratories is the glycine tolerance assay [3]. In contrast to Cff, Cfv fails to grow on media containing glycine 1% w ⁄ v, although some glycine-tolerant variants of Cfv (biovar intermedius) have been reported [6,8]. Glycine tolerance can be mediated by bacteriophages or spontaneous mutation, and may be highly dependent on the methods used [9,10]. Recommendations exist for performing glycine testing, but have not yet been adopted widely [10]. Commonly, clinical cases of C. fetus infection are reported following subspeciation by commercially available identification systems that do not contain the glycine tolerance test, or by molecular methods such as
10.1111/j.1469-0691.2005.01071.x
16S rDNA and 16S rRNA sequencing that do not determine the subspecies adequately [7,11–13]. Pulsed-field gel electrophoresis (PFGE)-DNA numerical analysis, amplified fragment length polymorphism (AFLP) analysis and PCR are effective methods for differentiating subspecies of C. fetus [7,14,15]. However, in a few cases, the results of subspeciation by AFLP and PFGE-DNA numerical analysis do not correlate with the results of biochemical and PCR typing, suggesting that distinct strains may be evolving in other geographical regions [7,14,16]. C. fetus may potentially be a new emerging zooanthroponotic pathogen, because the population at risk for systemic infections is increasing worldwide. The significance of international animal trade, and its relevance to the epidemiology of infectious disease in humans, has not yet been investigated extensively. Changes in food consumption in industrialised countries, with a trend towards undercooked or raw foods and unpasteurised milk, augment the risk of exposure to C. fetus, and might result in a change in its habitat [2]. Resistance to quinolones has been described, and relapse after termination of antibiotic therapy is a frequent occurrence [2,17]. Following collaborative efforts, we recently identified the first human isolate of C. fetus from a patient with underlying liver cirrhosis suffering from pneumonia-associated bacteraemia. This isolate was identified as Cfv by phenotyping methods and as Cff by AFLP and PCR (data available from corresponding author). Given that C. fetus continues to be considered as an underdiagnosed zooanthroponotic emerging human pathogen, and that subspecies discrimination remains challenging, we recommend that identification of human isolates of C. fetus should be performed in specialised diagnostic and veterinary laboratories by genotyping methods, such as AFLP, in addition to phenotyping, in order to build up a database for monitoring any change in habitat and to determine the true public health burden. W. M. Kalka-Moll*, M. A. P. Van Bergen, G. Plum, M. Kro¨nke, J. A. Wagenaar Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne, Goldenfelsstrasse 19–21, 50935 Cologne, Germany *E-mail: [email protected]
2005 Copyright by the European Society of Clinical Microbiology and Infectious Diseases
342 Clinical Microbiology and Infection, Volume 11 Number 4, April 2005
REFERENCES 1. Butzler J. Campylobacter, from obscurity to celebrity. Clin Microbiol Infect 2004; 10: 868–876. 2. Blaser MJ. Campylobacter fetus—emerging infection and model system for bacterial pathogenesis at mucosal surfaces. Clin Infect Dis 1998; 27: 256–258. 3. Nachamkin I. Campylobacter and Arcobacter. In: Murray PR, Baron EJ, Pfaller MA et al., eds. Manual of clinical microbiology, 7th edn. Washington, DC: ASM Press, 1999; 716– 726. 4. Blaser MJ. Campylobacter jejuni and related species. In: Mandell GL, Bennett JE, Dolin R, eds. Principle and practice of infectious diseases. Philadelphia, PA: Churchill Livingstone, 2000; 2276–2285. 5. Quinn TC, Goodell SE, Fennell C. Infections with Campylobacter jejuni and Campylobacter-like organisms in homosexual men. Ann Intern Med 1984; 101: 187–192. 6. Salama SM, Garcia MM, Taylor DE. Differentiation of the subspecies of Campylobacter fetus by genomic sizing. Int J Syst Bacteriol 1992; 42: 446–450. 7. On SL, Harrington CS. Evaluation of numerical analysis of PFGE-DNA profiles for differentiating Campylobacter fetus subspecies by comparison with phenotypic, PCR and 16S rDNA sequencing methods. J Appl Microbiol 2001; 90: 285– 293. 8. Ve´ron M, Chatelain R. Taxonomic study of the genus Campylobacter Sebald and Ve´ron and designation of the neotype strain for the type species Campylobacter fetus (Smith and Taylor) Sebald and Ve´ron. Int J Syst Bacteriol 1973; 23: 122–134.
9. Chang W, Ogg J. Transduction and mutation to glycine tolerance in Vibrio fetus. Am J Vet Res 1971; 32: 649–653. 10. On SL. Identification methods for campylobacters, helicobacters, and related organisms. Clin Microbiol Rev 1996; 9: 405–422. 11. Herve J, Aissa N, Legrand P et al. Campylobacter fetus meningitis in a diabetic adult cured by imipenem. Eur J Clin Microbiol Infect Dis 2004; 23: 722–724. 12. Harvey SM, Greenwood JR. Relationships among catalasepositive campylobacters determined by deoxyribonucleic acid hybridization. Int J Syst Bacteriol 1983; 33: 275–284. 13. Woo PC, Leung KW, Tsoi HW et al. Thermo-tolerant Campylobacter fetus bacteraemia identified by 16S ribosomal RNA gene sequencing: an emerging pathogen in immunocompromised patients. J Med Microbiol 2002; 51: 740–746. 14. Wagenaar JA, van Bergen MA, Newell DG et al. Comparative study using amplified fragment length polymorphism fingerprinting, PCR genotyping, and phenotyping to differentiate Campylobacter fetus strains isolated from animals. J Clin Microbiol 2001; 39: 2283–2286. 15. Duim B, Vandamme PA, Rigter A et al. Differentiation of Campylobacter species by AFLP fingerprinting. Microbiology 2001; 147: 2729–2737. 16. Vargas AC, Costa MM, Vainstein MH et al. Phenotypic and molecular characterization of bovine Campylobacter fetus strains isolated in Brazil. Vet Microbiol 2003; 93: 121–132. 17. Meier PA, Dooley DP, Jorgensen JH et al. Development of quinolone-resistant Campylobacter fetus bacteremia in human immunodeficiency virus-infected patients. J Infect Dis 1998; 177: 951–954.
2005 Copyright by the European Society of Clinical Microbiology and Infectious Diseases, CMI, 11, 341–342
The need to differentiate Campylobacter fetus subspecies isolated from humans The recent review in Clinical Microbiology and Infection by Butzler [1] described how collaboration between medical doctors and their veterinary colleagues during the 1970s led to the discovery of Campylobacter enteritis. Nowadays, Campylobacter spp. are a leading cause of foodborne illness in the industrialised world. Campylobacter jejuni and Campylobacter coli are the most frequent species isolated from humans. However, the public health burden of other Campylobacter spp., such as Campylobacter fetus, remains unmeasured [1]. C. fetus is thought to be an underdiagnosed cause of human disease because of its fastidious requirements for growth media and incubation atmosphere. In particular, selective media used routinely for the isolation of Campylobacter spp. contain antibiotics such as cephalothin and cefoperazone, to which C. fetus can be susceptible [2]. The species C. fetus is divided into subspecies fetus (Cff) and venerealis (Cfv) on the basis of their biochemical differences [3]. Cff is recovered commonly from the gastrointestinal tract of animals, including food-producing animals, but has also been isolated occasionally from local and systemic infections in humans [4]. In contrast, Cfv appears to be adapted to the bovine genital tract, where it causes bovine genital campylobacteriosis. There are only seven reported cases of its isolation from human patients: from the stools of two homosexual men; from two women with bacterial vaginosis; and from blood and other, non-defined, samples from three patients [4–7]. The only accepted phenotypic method for subspeciation in routine laboratories is the glycine tolerance assay [3]. In contrast to Cff, Cfv fails to grow on media containing glycine 1% w ⁄ v, although some glycine-tolerant variants of Cfv (biovar intermedius) have been reported [6,8]. Glycine tolerance can be mediated by bacteriophages or spontaneous mutation, and may be highly dependent on the methods used [9,10]. Recommendations exist for performing glycine testing, but have not yet been adopted widely [10]. Commonly, clinical cases of C. fetus infection are reported following subspeciation by commercially available identification systems that do not contain the glycine tolerance test, or by molecular methods such as
10.1111/j.1469-0691.2005.01071.x
16S rDNA and 16S rRNA sequencing that do not determine the subspecies adequately [7,11–13]. Pulsed-field gel electrophoresis (PFGE)-DNA numerical analysis, amplified fragment length polymorphism (AFLP) analysis and PCR are effective methods for differentiating subspecies of C. fetus [7,14,15]. However, in a few cases, the results of subspeciation by AFLP and PFGE-DNA numerical analysis do not correlate with the results of biochemical and PCR typing, suggesting that distinct strains may be evolving in other geographical regions [7,14,16]. C. fetus may potentially be a new emerging zooanthroponotic pathogen, because the population at risk for systemic infections is increasing worldwide. The significance of international animal trade, and its relevance to the epidemiology of infectious disease in humans, has not yet been investigated extensively. Changes in food consumption in industrialised countries, with a trend towards undercooked or raw foods and unpasteurised milk, augment the risk of exposure to C. fetus, and might result in a change in its habitat [2]. Resistance to quinolones has been described, and relapse after termination of antibiotic therapy is a frequent occurrence [2,17]. Following collaborative efforts, we recently identified the first human isolate of C. fetus from a patient with underlying liver cirrhosis suffering from pneumonia-associated bacteraemia. This isolate was identified as Cfv by phenotyping methods and as Cff by AFLP and PCR (data available from corresponding author). Given that C. fetus continues to be considered as an underdiagnosed zooanthroponotic emerging human pathogen, and that subspecies discrimination remains challenging, we recommend that identification of human isolates of C. fetus should be performed in specialised diagnostic and veterinary laboratories by genotyping methods, such as AFLP, in addition to phenotyping, in order to build up a database for monitoring any change in habitat and to determine the true public health burden. W. M. Kalka-Moll*, M. A. P. Van Bergen, G. Plum, M. Kro¨nke, J. A. Wagenaar Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne, Goldenfelsstrasse 19–21, 50935 Cologne, Germany *E-mail: [email protected]
2005 Copyright by the European Society of Clinical Microbiology and Infectious Diseases
342 Clinical Microbiology and Infection, Volume 11 Number 4, April 2005
REFERENCES 1. Butzler J. Campylobacter, from obscurity to celebrity. Clin Microbiol Infect 2004; 10: 868–876. 2. Blaser MJ. Campylobacter fetus—emerging infection and model system for bacterial pathogenesis at mucosal surfaces. Clin Infect Dis 1998; 27: 256–258. 3. Nachamkin I. Campylobacter and Arcobacter. In: Murray PR, Baron EJ, Pfaller MA et al., eds. Manual of clinical microbiology, 7th edn. Washington, DC: ASM Press, 1999; 716– 726. 4. Blaser MJ. Campylobacter jejuni and related species. In: Mandell GL, Bennett JE, Dolin R, eds. Principle and practice of infectious diseases. Philadelphia, PA: Churchill Livingstone, 2000; 2276–2285. 5. Quinn TC, Goodell SE, Fennell C. Infections with Campylobacter jejuni and Campylobacter-like organisms in homosexual men. Ann Intern Med 1984; 101: 187–192. 6. Salama SM, Garcia MM, Taylor DE. Differentiation of the subspecies of Campylobacter fetus by genomic sizing. Int J Syst Bacteriol 1992; 42: 446–450. 7. On SL, Harrington CS. Evaluation of numerical analysis of PFGE-DNA profiles for differentiating Campylobacter fetus subspecies by comparison with phenotypic, PCR and 16S rDNA sequencing methods. J Appl Microbiol 2001; 90: 285– 293. 8. Ve´ron M, Chatelain R. Taxonomic study of the genus Campylobacter Sebald and Ve´ron and designation of the neotype strain for the type species Campylobacter fetus (Smith and Taylor) Sebald and Ve´ron. Int J Syst Bacteriol 1973; 23: 122–134.
9. Chang W, Ogg J. Transduction and mutation to glycine tolerance in Vibrio fetus. Am J Vet Res 1971; 32: 649–653. 10. On SL. Identification methods for campylobacters, helicobacters, and related organisms. Clin Microbiol Rev 1996; 9: 405–422. 11. Herve J, Aissa N, Legrand P et al. Campylobacter fetus meningitis in a diabetic adult cured by imipenem. Eur J Clin Microbiol Infect Dis 2004; 23: 722–724. 12. Harvey SM, Greenwood JR. Relationships among catalasepositive campylobacters determined by deoxyribonucleic acid hybridization. Int J Syst Bacteriol 1983; 33: 275–284. 13. Woo PC, Leung KW, Tsoi HW et al. Thermo-tolerant Campylobacter fetus bacteraemia identified by 16S ribosomal RNA gene sequencing: an emerging pathogen in immunocompromised patients. J Med Microbiol 2002; 51: 740–746. 14. Wagenaar JA, van Bergen MA, Newell DG et al. Comparative study using amplified fragment length polymorphism fingerprinting, PCR genotyping, and phenotyping to differentiate Campylobacter fetus strains isolated from animals. J Clin Microbiol 2001; 39: 2283–2286. 15. Duim B, Vandamme PA, Rigter A et al. Differentiation of Campylobacter species by AFLP fingerprinting. Microbiology 2001; 147: 2729–2737. 16. Vargas AC, Costa MM, Vainstein MH et al. Phenotypic and molecular characterization of bovine Campylobacter fetus strains isolated in Brazil. Vet Microbiol 2003; 93: 121–132. 17. Meier PA, Dooley DP, Jorgensen JH et al. Development of quinolone-resistant Campylobacter fetus bacteremia in human immunodeficiency virus-infected patients. J Infect Dis 1998; 177: 951–954.
2005 Copyright by the European Society of Clinical Microbiology and Infectious Diseases, CMI, 11, 341–342