产肠毒素大肠埃希菌活的非可培养状态实验室初步研究

Primary investigation on variable but nonculturable-state of enterotoxigenic Escherichia coli in Vitro

目的初步研究产肠毒素大肠埃希菌(ETEC)7株“活的非可培养状态”菌株的形态学、抗原特性以及复苏后生物学、抗原特性、致病性、药物敏感性等特性。方法运用常规革兰染色、动物肠腔复苏、复苏菌株致病性、血清学凝集、生化鉴定、体外药物敏感等试验观察“活的非可培养状态” ETEC及复苏后生物学特性的变异。结果这7株“活的非可培养状态”ETEC除菌体营养细胞缩小成球形休眠体外,其他特性均无明显变异,仍保留着较强的致病力。结论细菌“活的非可培养状态”的存在,提示在传染病日常监测过程中应注意这种细菌的存在状态。

Objective 7 variable but noneulturable state strains of Enterotoxigenic Escherichia coli （ETEC） during the routine bacterial subculture were found in our lab and their morphology and antigen studied. Biological features,antigens and pathogenicity of the revertants were also tested and compared to that of the initial strains in order to detect their variations. Methods Biological variations between the variable but nonculturable-state and the revertant of every strain were detected, using the routine gramL staining,reverting the isolates in animal intestinal, reverting their pathogenicity, serological agglutination, biochemical identifications and antibiotic resistance tests. Results For the 7 variable but noncuhurablestate strains of ETEC,other than the trains that had changed into sphero vegetale cells, there were no other obvious variations found. However, high pathogenicity of these strains still remained. Conclusion The presence of variable but nonculturable-state strains suggested that the routine method of bacteria storage should be changed and more attention should be paid to realize the existence of this kind of bacteria during the routine surveillance of the communicable diseases.