Anaerobic intestinal spirochetes of the genus Brachyspira colonize the large intestine (1). Most Brachyspira species have a restricted host range, whereas Brachyspira (formerly Serpulina) pilosicoli colonizes a variety of animal and bird species and humans. B. pilosicoli is an important colonic pathogen of pigs and chickens (2). It occurs at high prevalence rates in humans in developing countries and in male homosexuals and HIV-positive persons in industrialized countries (3). Its potential as a human pathogen was emphasized after its identification in the bloodstream of a series of debilitated persons (4)

Hampson, David J.

La, Tom

Oxberry, Sophy L.

Emerging Infectious Diseases

English

PubMed

David J. Hampson

Sophy L. Oxberry

Tom La

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Potential for Zoonotic Transmission of Brachyspira pilosicoli

Hampson, D.J.

Oxberry, S.L.

La, T.

Research Repository

LETTERSEmerging Infectious Diseases • www.cdc.gov/eid • Vol. 12, No. 5, May 2006 8696. Koprowski H. The mouse inoculation test.In: Meslin FX, Kaplan MM, Koprowski H,editors. Laboratory techniques in rabies.Geneva: World Health Organization; 1996.p. 80–7.7. Orciari LA, Niezgoda M, Hanlon CA,Shaddock JH, Sanderlin DW, Yager PA, etal. Rapid clearance of SAG-2 rabies virusfrom dogs after oral vaccination. Vaccine.2001;19:4511–8.8. Centers for Disease Control andPrevention. Investigation of rabies infec-tions in organ donor and transplant recipi-ents—Alabama, Arkansas, Oklahoma, andTexas, 2004. MMWR Morb Mortal WklyRep. 2004;53:1–3.9. Willoughby RE Jr, Tieves KS, HoffmanGM, Ghanayem NS, Amlie-Lefond CM,Schwabe MJ, et al. Survival after treatmentof rabies with induction of coma. N Engl JMed. 2005;352:2508–14.10. David D, Yakobson B, Rotenberg D,Dveres N, Davidson I, Stram Y. Rabiesvirus detection by RT-PCR in decomposednaturally infected brains. Vet Microbiol.2002;87:111–8.Address for correspondence: Rafael Oliveira,Instituto Pasteur, Laboratory of Diagnosis, AvPaulista, 393 Cerqueira Cesar São Paulo, SãoPaulo 01311-001, Brazil; email: rafaeldenovaes@yahoo.com.brPotential forZoonoticTransmission ofBrachyspira pilosicoli To the Editor: Anaerobic intestin-al spirochetes of the genusBrachyspira colonize the large intes-tine (1). Most Brachyspira specieshave a restricted host range, whereasBrachyspira (formerly Serpulina)pilosicoli colonizes a variety of ani-mal and bird species and humans. B.pilosicoli is an important colonicpathogen of pigs and chickens (2). Itoccurs at high prevalence rates inhumans in developing countries andin male homosexuals and HIV-posi-tive persons in industrialized coun-tries (3). Its potential as a humanpathogen was emphasized after itsidentification in the bloodstream of aseries of debilitated persons (4). B. pilosicoli isolates from humansand other species have been usedexperimentally to colonize chicks,piglets, and mice (5–7). While theseresults indicate that the B. pilosicolistrains used lacked host-species speci-ficity, few data exist on whether natu-ral zoonotic spread of B. pilosicolistrains occurs. In 1 study that usedpulsed-field gel electrophoresis(PFGE) to type isolates from PapuaNew Guinea, 2 dogs were colonizedwith B. pilosicoli isolates with thesame PFGE types as those from vil-lagers. However, the higher preva-lence of colonization with B. pilosi-coli in humans than dogs suggestedthat the dogs were infected withhuman isolates, probably throughconsumption of human feces (8). Multilocus enzyme electrophoresis(MLEE) has been used to study varia-tion in B. pilosicoli isolates; moststudies have focused on isolates fromonly 1 or 2 host species (8–10).Generally, B. pilosicoli isolates arediverse, and a lack of linkage disequi-librium in the MLEE data for humanisolates suggests that the species isrecombinant (8).We used MLEE to investigate rela-tionships between 107 B. pilosicoliisolates of diverse geographic andhost-species origins and the B. aalbor-gi type strain (NCTC 11492T). Isolateswere selected on the basis of theirdiverse origins and availability in theMurdoch University culture collec-tion. They originated from feces of 34pigs, 19 chickens, 13 ducks, 1 rhea, 25humans, and 4 dogs; from 7 humanblood samples; and from 4 watersources frequented by waterfowl.Isolates originated from Australia,Canada, France, Italy, the Netherlands,Oman, Papua New Guinea, the UnitedKingdom, and the United States.The MLEE method used was aspreviously described (8–10); the elec-trophoretic mobility of 15 constitutiveenzymes was analyzed. Variations inelectrophoretic mobility were inter-preted as representing products of dif-ferent alleles at each enzyme locus.Isolates with identical enzymatic pro-files at 15 loci were grouped into anelectrophoretic type (ET). Geneticdistance between ETs was calculatedas the proportions of loci at which dis-similar alleles occurred. PHYLIP ver-sion 3.51c (Phylogeny InferencePackage, University of Washington,Seattle, WA, USA) was used to ana-lyze data and generate a dendrogramby using the unweighted pair-groupmethod with arithmetic mean cluster-ing fusion strategy. Genetic diversity(h) was calculated for the number ofETs as (1 – Σpi2)(n/n – 1), where pi isthe frequency of the indicated alleleand n is the number of ETs.B. pilosicoli isolates were dividedinto 80 ETs (mean 1.35 isolates perET) (Figure). B. aalborgi NTCC11492T was distinct in ET81. The B.pilosicoli isolates were diverse, withan h value of 0.41. Generally, they didnot cluster according to host speciesof origin, and isolates from a givenspecies were distributed throughoutthe dendrogram. Isolates from birdswere more diverse than those fromhumans and pigs. Eight ETs containedmultiple isolates, in each case fromthe same host species (either chickensor pigs). In 4 cases these originatedfrom different countries: ET47 con-tained 2 Australian porcine isolatesand 2 from the United States; ET53contained 2 Australian porcine iso-lates and Scottish porcine type strainP43/6/78T; ET54 contained 2Australian and 2 Canadian porcineisolates; ET65 contained 1 Dutch and1 US chicken isolate. Although human isolates did notshare an ET with isolates from otherspecies, they were frequently closelyrelated, differing in 1 allele. Thisoccurred with US and Australian pigLETTERSisolates in ET47 and a human isolatefrom Oman in ET48; an Australianpig isolate in ET61 and a UK humanisolate in ET62; an isolate from anAustralian HIV-positive person inET64, and 1 Dutch and 1 US chickenisolate in ET65; and a Papua NewGuinea canine isolate in ET68 and aFrench human blood isolate in ET69. The distribution continuum of iso-lates of diverse host species and geo-graphic origin was consistent with alack of species specificity and sug-gests that B. pilosicoli isolates natu-rally have the potential to be transmit-ted between species. Even shouldthere be some unexpected species-specific barrier preventing “true” ani-mal or bird isolates from colonizinghumans, animals have been colonizedby human isolates, and thus could actas a reservoir of these for subsequentretransmission to humans. The resultssuggest that zoonotic transfer of B.pilosicoli isolates likely occurs innature, e.g., after exposure to infectedanimals or birds, their feces, or con-taminated water.David J. Hampson,* Sophy L. Oxberry,* and Tom La**Murdoch University, Murdoch, WesternAustralia, Australia References1. Stanton TB. Physiology of ruminal andintestinal spirochaetes. In: Hampson DJ,Stanton TB, editors. Intestinal spirochaetesin domestic animals and humans.Wallingford (UK): CAB International;1997. p. 7–45.2. Hampson DJ, Duhamel GE. Porcinecolonic spirochetosis/intestinal spirocheto-sis. In: Straw B, Zimmerman JJ, D’AllaireS, Taylor DJ, editors. Diseases of swine. 9thed. Ames (IA): Iowa State University Press;2006. p. 755–67.3. Hampson DJ. Intestinal spirochaetes. In:McIver CJ, editor. A compendium of labo-ratory diagnostic methods for common andunusual enteric pathogens–an Australianperspective. Sydney: ASM Publications;2005. p. 101–8. 4. Trott DJ, Jensen NS, Saint Girons I,Oxberry SL, Stanton TB, Lindquist D,Hampson DJ. Identification and characteri-zation of Serpulina pilosicoli isolates fromthe blood of critically-ill patients. J ClinMicrobiol. 1997;35:482–5.5. Trott DJ, McLaren AJ, Hampson DJ.Pathogenicity of human and porcine intes-tinal spirochaetes in day-old specificpathogen free chicks: an animal model ofintestinal spirochetosis. Infect Immun.1995;63:3705–10.6. Trott DJ, Huxtable CR, Hampson DJ.Experimental infection of newly weanedpigs with human and porcine strains ofSerpulina pilosicoli. Infect Immun.1996;64:4648–54.7. Sacco RE, Trampel DW, WannemuehlerMJ. Experimental infection of C3H micewith avian, porcine, or human isolates ofSerpulina pilosicoli. Infect Immun.1997;65:5349–53.8. Trott DJ, Mikosza ASJ, Combs BG,Oxberry SL, Hampson DJ. Populationgenetic analysis of Serpulina pilosicoli andits molecular epidemiology in villages inthe Eastern Highlands of Papua NewGuinea. Int J Syst Bacteriol. 1998;48:659–68.9. Lee JI, Hampson DJ, Lymbery AJ, HardersSJ. The porcine intestinal spirochaetes:identification of new genetic groups. VetMicrobiol. 1993;34:273–85.10. McLaren AJ, Trott DJ, Swayne DE,Oxberry SL, Hampson DJ. Genetic andphenotypic characterization of intestinalspirochetes colonizing chickens, and allo-cation of known pathogenic isolates tothree distinct genetic groups. J ClinMicrobiol. 1997;35:412–7.Address for correspondence: David J.Hampson, School of Veterinary and BiomedicalSciences, Murdoch University, Murdoch,Western Australia 6150, Australia; email:d.hampson@murdoch.edu.au870 Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 12, No. 5, May 2006Figure. Dendrogram showing relationships between 107 isolates of Brachyspira pilosicolioriginating from various host species located in electrophoretic types (ETs) 1–80 and B.aalborgi NCTC 11492T located in ET81.All material published in EmergingInfectious Diseases is in the publicdomain and may be used and reprintedwithout special permission; proper cita-tion, however, is required.

Potential for zoonotic transmission of Brachyspira pilosicoli

Experimental infection of C3H mice with avian, porcine, or human isolates of Serpulina pilosicoli. Infect Immun.

Experimental infection of newly weaned pigs with human and porcine strains of Serpulina pilosicoli. Infect Immun.

Genetic and phenotypic characterization of intestinal spirochetes colonizing chickens, and allocation of known pathogenic isolates to three distinct genetic groups. J Clin Microbiol. 1997;35:412–7. Address for correspondence:

Identification and characterization of Serpulina pilosicoli isolates from the blood of critically-ill patients.

Intestinal spirochaetes.

Pathogenicity of human and porcine intestinal spirochaetes in day-old specific pathogen free chicks: an animal model of intestinal spirochetosis. Infect Immun.

Physiology of ruminal and intestinal spirochaetes.

Population genetic analysis of Serpulina pilosicoli and its molecular epidemiology in villages in the Eastern Highlands of Papua New Guinea.

Porcine colonic spirochetosis/intestinal spirochetosis.

The porcine intestinal spirochaetes: identification of new genetic groups. Vet Microbiol.

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Potential for Zoonotic Transmission of Brachyspira pilosicoli

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