TYZZERS INFECTION - HOST-SPECIFICITY OF CLOSTRIDIUM PILIFORME ISOLATES

Tyzzer's disease, a well-recognized syndrome in numerous laboratory an imal species, is caused bg the obligate intracellular bacterium, Clost ridium piliforme. Distinct isolates of C. piliforme from various labor atory animal species have been identified based on protein and antigen ic heterogeneity. The goal of this study was to examine the host speci ficity of three well characterized isolates of C. piliforme. Groups of mice, rats, and hamsters were experimentally infected with isolates o btained from a naturally infected mouse (Mi), a naturally infected rat (R1), and a naturally infected hamster (H2). To assess infection stat us, animals were monitored serologically for antibody to C. piliforme over a 12-week period. Evaluation of results indicated that the M1 iso late infected rats and mice but not hamsters, whereas the R1 and H2 is olates infected only the host species from which the isolates were ori ginally obtained. These findings suggest that C. piliforme isolates ca n be categorized into two types: 1) cross-infective isolates, such as M1, which can infect more than one laboratory animal species, and 2) i solates, such as R1 and H2, which have a more limited host range withi n laboratory animal species. These results emphasize the need to consi der the host specificity of C. piliforme isolates when investigating o utbreaks of Tyzzer's disease.