肠出血性大肠杆菌O157：H7L型及其意义的研究

目的诱导肠出血性大肠杆菌O157：H7（以下简称O157：H7）L型观察其特性及意义。方法羧苄青霉素和氨苄青霉素纸片法诱导。比技L型，与原菌生化特性、药物敏感性，L型小鼠灌胃，取肝、结肠、直肠组织分离培养，以观察体内L型存留情况。结果经L型鉴定，如电镜超薄切片等证实细胞壁缺损。L型生化反应比原菌大为减弱、O157凝集为阴性，对抗生素敏感性除卡那霉素（P＜0．01）外，其余同原菌无显著性差别（P＞0．05）。小鼠体内肠道可存留L型，其可回复为细菌型。结论两种抗生素均可诱导O157：H7形成L型。给实验室诊断带来极大困难。提示L型有可能造成该菌感染传播及暴发流行的危险。

STUDIES ON HECE O157: H7 L-FORM AND ITS SIGNIFICANCE

Aim To observe the characteristics of induced EHEC O157: H7 (O157: H7) L-form. Method To usepaper disk method with Carbenicillin and Ampicillin. To compare the difference of biochemical features and drug sensitivity be-tween O157: H7 and its L-form. L-form was fed intragastrically into the mices,f rom their livers,colons and intertines. L-formwas isolated and cultured to observe the remains. Result It was detected by L-form identification,as was verified by u1trathinsection under election microscopes,that deficiency in cell walls existed. Biochemical reaction of L-f rom was decreased greatlywith that of Ol57: H7. Agglutination of O157 is negative. Its sensivity to antibiotic (except Kanamycin PrtO. O1) showed nosignificant difference(P>o- o5)- With the mouse's body remains of L-form could be found within its internal intestinal canal,which could lead to revert to their parental forms. Concluslon The two antibiotics can lead to induced Ol57: H7 L-form,which brings great difficulty for diagnosis in laboratory work- It is suggested that L-form may result in the spread and eventhe outburst of EHEC O157 1 H7.