An Outbreak of Shigellosis in a Psychiatric Hospital in Taichung City

Sung-Hsi Wei

2009 Vol.25 NO.12

Correspondence Author: Sung-Hsi Wei


On November 6, 2009, a hospital in Taichung City reported two cases of suspected shigellosis to the Third branch of Taiwan Centers for Disease Control. Both patients were transferred from a psychiatric hospital because of diarrhea from a suspected foodborne outbreak. An outbreak investigation was commenced. The psychiatric hospital has 340 patients. During November 2-20, 2009, there were a total of 63 patients with diarrhea and fever. Of these, 18 patients had Shigella flexneri 4a isolated from their rectal swab or stool cultures. In addition, Bacillus cereus was isolated from some leftover food. Disease incidence was increased among patients on soft diet (odds ratio: 9.0, 95% confidence interval 4.3-19.4). Pulsed-field gel electrophoresis of 5 of the Shigella flexneri isolates showed that the outbreak was of the same lineage, however, genetic differentiation had already occurred, indicating that the bacteria has been circulating in the hospital for some time.
Keywords: Shigella, shigellosis, cluster, psychiatry, Bacillus cereus