Husslein V, Chakraborty T, Carnahan A, Joseph S W
Institut für Genetik und Mikrobiologie, Universität Würzburg, Federal Republic of Germany.
Clin Infect Dis. 1992 May;14(5):1061-8. doi: 10.1093/clinids/14.5.1061.
A large group of aeromonads and other enteric microorganisms were assayed for the presence of the aerolysin gene with use of DNA-DNA hybridization. Two DNA fragments corresponding to the regulatory region (aerC) and the structural gene (aerA) were used as probes for the detection of the aerolysin gene in these strains. Sequences corresponding to the aerolysin structural gene were widespread among Aeromonas isolates. In contrast, the aerC probe was much more selective, and sequences corresponding to the aerC region were detected in only a small subset of strains. Concurrent studies using numerical taxonomy and DNA hybridization with the aerC probe on a larger set of strains led to the identification of a distinct cluster of 14 presumed atypical Aeromonas sobria strains. These strains have recently been grouped into a new species designated Aeromonas trota. Hence, the DNA fragment aerC used in the study is a species-specific gene probe for A. trota. The ability of the aerC probe to detect strains belonging to a single species suggests that there is selection pressure to maintain the clonality of this species. These results have important implications with respect to the evolution of "pathogenic profiles" among these medically important bacteria.
使用DNA-DNA杂交技术对一大群气单胞菌和其他肠道微生物进行了气溶素基因检测。两个分别对应调控区（aerC）和结构基因（aerA）的DNA片段被用作探针，用于检测这些菌株中的气溶素基因。对应气溶素结构基因的序列在气单胞菌分离株中广泛存在。相比之下，aerC探针的选择性更强，仅在一小部分菌株中检测到对应aerC区域的序列。同时使用数值分类法以及用aerC探针与更多菌株进行DNA杂交的研究，鉴定出了14株推测为非典型温和气单胞菌的独特菌株群。这些菌株最近被归为一个新物种，命名为豚鼠气单胞菌。因此，该研究中使用的DNA片段aerC是豚鼠气单胞菌的种特异性基因探针。aerC探针检测属于单一物种菌株的能力表明，存在维持该物种克隆性的选择压力。这些结果对于这些医学上重要细菌的“致病谱”进化具有重要意义。
