Abstract
Following the death of a hooded pitta (Pitta sordida) from the zoonotic bacterium, Yersinia pseudotuberculosis, at the Sequoia Park Zoo, Eureka, California, USA, in December 2001, we surveyed cloacal swabs and feces of 44 birds and 31 mammals, January through May 2002; four soil samples also were evaluated. Cold storage (4°C) incubation for 11–12 months in trypticase soy broth was followed by isolation on Yersinia Selective Agar/Antimicrobic Supplement CN. Suspect strains were identified with an API 20E (bioMerieux) system and biotyping confirmed by the methods of Wauters, et al.2-3 Eight strains were evaluated by pulsed-field gel electrophoresis.1 Serotyping of one strain was attempted by slide agglutination.
No Yersinia pseudotuberculosis was found, including in eight samples of rat feces, supporting the notion that no enzootic focus for this bacterium is present at the zoo. Yersinia enterocolitica biotype 1A was isolated from a sacred ibis (Threskiornis aethiopicus), a cedar waxwing (Bombycilla cedrorum), an unidentified bird in the aviary, a nyala (Tragelaphus angasii), a black bear (Ursus americanus), and one soil sample; this was a 7.6% prevalence for all samples taken. One biotype 1A strain (ibis) tested by slide agglutination was too rough for serotyping; other strains were not serotyped. Based on a pulsed-field gel electrophoresis of eight biotype 1A strains, we observed 5 distinct profiles of Y. enterocolitica—evidence for several sources of the bacteria rather than a clone stemming from a single introduction. In addition, Yersinia frederiksenii was isolated from a nyala and Y. mollaretii was collected from an Argus pheasant (Arguslanus argus). There were no apparent patterns in Yersinia spp. isolations related to host class or geographic location within the zoo. Serratia spp. (10% of all samples) and Providencia spp. (5%) also were isolated from both birds and mammals.
Literature Cited
1. Division of Bacterial and Mycotic Diseases, National Centers for Infectious Diseases. Standardized Molecular Subtyping of Foodborne Bacterial Pathogens by Pulsed-Field Gel Electrophoresis. Centers for Disease Control. Wauters G, Kandolo K, Janssens M. 1987. Revised biogrouping scheme of Yersinia enterocolitica. Contr Microbiol Immunol. 2002;9:14–21.
2. Wauters G, Janssens M, Steigerwalt AG, Brenner DJ. Yersinia mollaretii sp. nov. and Yersinia bercovieri sp. nov. formerly called Yersinia enterocolitica biogroups 3A and 3B. Int J Sys Bacteriol. 1988;38:424–429.