DNA探针检测痢疾杆菌和侵袭性大肠杆菌的研究——17kb和2.5kb探针及其与Sereny试验的比较

用~(32)P标记17kb和2.5kb两个侵袭基因小片段作探针、分别与168株痢疾杆菌、60株侵袭性大肠杆菌及300株沙门氏菌属等作菌落杂交。结果表明:两个探针均只与携带120—140Md侵袭性大质粒的菌株杂交,而未见与其它对照株产生非特异阳性,但17kb探针能与Is_1序列产生可见的杂交背景。Sereny试验表明,探针杂交阳性的菌株,并非都能引起豚鼠眼结膜炎;而Sereny试验阳性者,经传代保存也可转变为阴性。

Comparison between two DNA Probes and Sereny Test For Examination of Bacillus Dysenteriae and Enteroinvasive Es- cherichia Coli Strains

Tso invasive gene fragments of 17kb and 2. 5 kb by using ~(32)P-labelled were used as probes. A total 228 strains of bacillus Dysenteriae and enter- oinvasive Escherichla coli were examined by colony hybridization. Both probes showed identical results. All of them hybridized only with the strains carrl- ng a 120- 140megadalton invason large plasmid and there were no non-specific hybridization with 300 strains of Salmonella and other Gram's negative Enterobacteria, which were used as the negative control. But the 17kb probe can produced visible hybridization reaction with IS1 sequence. In addition, probes positive strains did not all cause keratocon- kunctivitis in guinea pigas, and Sereny test positive strains may tarn to negative in long-term subcul- ture.