某精神專科醫院桿菌性痢疾群突發事件調查──外籍看護工之出入境省思

An Outbreak of Shigellosis Transmitted by a Foreign Employee at a Psychiatric Hospital

中台灣某地區型精神專科醫院於2012年6月19日起陸續有病人出現發燒、水瀉等症狀，轉診後疑腸胃炎感染。經送驗直腸拭子（rectal swab），確認1名病人感染志賀氏桿菌（Shigella sonnei），通報衛生局進行調查，至7月21日止23人疑似症狀個案中，有4人為桿菌性痢疾確定病例，致病菌皆為志賀氏桿菌D群血清型（Shigella sonnei），疾管署資料顯示該菌株為越南境外移入，在第9病房有1名越南籍女外籍看護工曾於5月17日至30日返回越南，雖該員並無症狀仍予採檢，確診為S. sonnei陽性之無症狀帶菌者，所有陽性菌株經疾管署中區管制中心脈衝電場膠電泳分析（Pulse-Field Gel Electrophoresis, PFGE）為同一來源變異株。研判此次疫情為桿菌型痢疾感染群突發，指標個案為越南籍女外籍看護工，該員於5月份出境後感染，導致機構內的感染。精神專科醫院為人口密集及病人自我照顧功能缺失等特性，感染管制同仁對於高度傳染性的桿菌型痢疾須時時警覺，本研究證實機構內因加強外籍工作人員返國後篩選機制，避免導致在機構內出現群聚傳染事件。

In June 2012, an outbreak of shigellosis occurred at a local 350-bed psychiatric hospital in central Taiwan. A total of 23 patients with fever, diarrhea, and other symptoms were suspected of having infectious enteritis. Shigella sonnei serotype D group was isolated from the rectal swab specimens of 3 patients and a foreign employee who had recently traveled back from her home country, Vietnam. The S. sonnei strains showed a distinctive pulsed-field gel electrophoresis pattern that was similar to that of strains isolated and imported from Vietnam that had been collected in the Centers for Disease Control and Prevention database. All infected patients were transferred to the medical center for treatment. Furthermore, strict infection control measures were implemented, and prophylactic antibiotic treatment was given. The outbreak ended 50 days after the onset of the first episode. Infectious diseases could easily occur and spread in psychiatric hospitals because of their environment. We report this investigation to remind infection control workers that foreign employees could be transmitters of infection, leading to an outbreak in a hospital.