VIRULENCE PLASMID IN YERSINIA-ENTEROCOLITICA O 3 MURINE ORIGIN/

Background: Pathogenic strains of Yersinia enterocolitica harbor a vir ulence plasmid of 45-48 megadalton that can be detected using differen t techniques. Rodents are important reservoirs of Y enterocolitica. Ai m: To investigate the carrier status of Y enterocolitica in murine rod ents. Material and methods: Two hundred sixty one mice and rats were c aptured in rural and urban areas of Valdivia. Y enterocolitica was cul tured from viscera and fecal homogenates. Virulence plasmids were dete cted using crystal violet binding. Results: Thirteen Y enterocolitica strains were isolated from 11 rodents. Ten strains belonged to the bio type 1 and three to the biotype 4, serotype O:3. The most frequently i nfected rodent species were R norvergicus (20%), followed by A longipi lis (11%), A olivaceus (2%) and O longicaudatus (2%). Conclusions: Rod ents, and specially the domestic rat, can be an important source of Y enterocolitica infection for human and susceptible animal species.