Epidemiological study of Yersinia enterocolitica and Yersinia pseudotuberculosis infections in Shimane Prefecture, Japan.

: In Shimane Prefecture, Japan, 175 Yersinia enterocolitica isolates from 6,479 stools and 347 appendixes of patients were separated into biotype 3B (VP-, sorbose-, inositol-) serotype O3 phage type II (22 isolates); biotype 4 (84 isolates), biotype 4 (ornithine-) (16 isolates) and biotype 4 (maltose-) (9 isolates) of serotype O3 phage type VIII, biotype 2 serotype O9 (1 isolate) and biotype 1 (43 isolates). This may be the first documentation of isolation of Y. enterocolitica biotype 3B serotype O3 phage type II from patients. Twenty-three Yersinia pseudotuberculosis isolates from stools of 23 patients were grouped into serotypes IB (13 isolates), III (2 isolates) and IVB (8 isolates). Clinical manifestations were more numerous in Y. pseudotuberculosis infections than Y. enterocolitica O3 infections. Y. enterocolitica O3 was more frequently isolated between summer and autumn but Y. pseudotuberculosis and Y. enterocolitica biotype 1 were isolated between winter and spring. Secondary infection with Yersinia among close family members was frequent. Y. enterocolitica O3 and Y. pseudotuberculosis infected persons excreted 10(4) to 10(9) viable cells per g stool during 27 and 19 days, but Y. enterocolitica biotype 1 strains were detected only when using enrichment techniques. Serological responses were not observed in under 2 year old persons infected with Y. enterocolitica O3.