A multi-prefectural outbreak of Shigella sonnei infections associated with eating oysters in Japan.

Among roughly one thousand incidents of shigellosis annually in Japan, approximately 70% of the cases are estimated to be associated with overseas travel. However, at the end of 2001, reports of domestically acquired Shigella sonnei infections suddenly increased. We report here the first multi-prefectural outbreak of Shigella sonnei infections linked to the consumption of imported oysters in Japan at the end of 2001. Isolates of S. sonnei from patients epidemiologically linked to eating contaminated oysters and from the imported oysters themselves showed an indistinguishable pulsed-field gel electrophoresis pattern and drug resistance pattern.