腸管出血性大腸菌感染症

Enterohemorrhagic Escherichia coli Infection

要旨　腸管出血性大腸菌O157感染症の臨床像について，その内視鏡所見を中心に概説した．O157 出血性大腸炎の典型例では，特徴的な内視鏡所見である炎症勾配と縦走潰瘍を呈した．すなわち，病変部位は盲腸から直腸まで広範囲に連続性にみられたが，炎症所見は右側結腸で最も強く，左側結腸に移行するにつれて漸減した．また約半数の例で横行結腸や下行結腸に縦走潰瘍がみられた．血便患者の内視鏡検査においてこれらの所見が得られれば，内視鏡所見からO157 が起炎菌であると推定可能であり，内視鏡室や病室での汚染防止，二次感染の予防，さらには溶血性尿毒症症候群や脳症の発生にあらかじめ注意を払える点で臨床上有用である．

　The clinical and colonoscopic features of enterohemorrhagic Escherichia coli O157 : H7（O157）infection were reviewed. In patients in the acute infectious phase of O157-induced hemorrhagic colitis, colonoscopy revealed characteristic findings of an inflammatory gradient and longitudinal ulcer. That is, though the inflammatory lesions extended continuously over a wide area from the cecum to the rectum, inflammation was more severe in the right-side colon and declined as it transferred to the left-side colon. Additionally, in about half of the patients, longitudinal ulcers were observed in part of the transverse colon and/or the descending colon. These findings gleaned during colonoscopy would be highly indicative of the probability of O157 as the causative pathogen in patients with hemorrhagic colitis, and these same findings would indicate the need for precautions against bacterial pollution in endoscopic units and sick rooms, and as a signal of possible secondary infections, and as a clue to whether hemolytic uremic syndrome might develop.