Typing of Yersinia pestis isolates from the state of Ceara, Brazil

Aims: To investigate whether modifications in Yersinia pestis isolates from three plague foci from the state of Ceara, Brazil, had occurred over the years as a consequence of genetic adaptation to the environment. Methods and Results: The isolates were studied with respect to susceptibility to antimicrobial drugs, plasmid and protein profiling, pigmentation on Congo red-agar plates, and the presence of some pathogenicity genes using PCR. Most of the expected virulence markers were detected in the cultures examined. There was no evidence of any alteration that could be associated with their origin ( patients, rodents and fleas) or period of isolation (1971-1997). Conclusions, Significance and Impact of the Study: Phenotypic or genotypic changes were not detected in the cultures examined. However, the results obtained will serve as a reference to follow the evolution of Y. pestis in these foci.