An outbreak of diarrhea in Mandera, Kenya, due to Escherichia coli serogroup O-nontypable strain

2018 Fiscal Year Final Research Report

• Project/Area Number: 15K08477
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Bacteriology (including mycology)
• Research Institution: Yokohama College of Pharmacy (2017-2018); Fujita Health University (2015-2016)
• Principal Investigator: Ochi Sadayuki 横浜薬科大学, 薬学部, 教授 (80268705)
• Research Collaborator: Ichinose Yoshio
• Project Period (FY): 2015-04-01 – 2019-03-31
• Keywords: 感染症疫学 / 下痢症 / 大腸菌

Outline of Final Research Achievements

In an outbreak of gastroenteritis on 16 December 2009, in Mandera, Kenya, Escherichia coli O-untypable (OUT) strain was isolated from stool specimens of patients (18/24, 75%). The isolates showed the similar DNA banding pattern in pulsed-field gel electrophoresis after digestion with the restriction enzymes NotI or XbaI. The cell-free culture filtrate of EASTEC (E. coli that does not exhibit any diarrheagenic characteristics other than enteroaggregative E. coli heat-stable enterotoxin 1 gene) strain isolated from the outbreak case induced a considerable amount of fluid accumulation (FA) in suckling mouse intestine, indicating production of an enterotoxic factor(s). These results identify EASTEC as the etiological agent of the diarrheal outbreak in Mandera.

Free Research Field

細菌学

Academic Significance and Societal Importance of the Research Achievements

世界第5位の死因である下痢性疾患は、今なお深刻な問題の疾患である。私は、ケニアで発生した原因菌不明の下痢症アウトブレイクについて検討し、病原因子として腸管凝集性大腸菌が持つ耐熱性エンテロトキシン1遺伝子のみを保有するEASTECと呼ばれる大腸菌が原因となって下痢症アウトブレイクが引き起こされたことを示した。本研究は、迅速な原因菌の同定が不可欠な下痢症の予防、発生時の流行阻止、そして、適切な治療の領域に貢献すると考える。