Prada J, Zimmermann S, Stephan R, Beutin L
Robert Koch-Institut des Bundesgesundheitsamtes, Berlin.
Zentralbl Bakteriol. 1992 Jan;276(2):152-64. doi: 10.1016/s0934-8840(11)80002-2.
Three different phenotypes of hemolysis on blood-agar were detected when 58 isolates of Escherichia coli were investigated for alpha-hemolysin synthesis. In strains with chromosomally encoded alpha-hly genes, phenotype I (large and clear hemolysis zones) corresponded with high hemolytic activity and with a 17.2 kb size BamHI restriction fragment hybridizing with an alpha-hly-specific gene probe. Phenotype II (small and turbid hemolysis zones) was associated with low hemolytic activity and generally with a 12.8 kb size hybridizing BamHI restriction fragment. An intermediate phenotype (type I/II) was found in a few strains with moderate hemolytic activity. This correlation between hemolytic phenotype and activity was not found in E. coli carrying alpha-hly plasmids. Type I strains differed from all others in the promotor region of their 17.2 kb size BamHI fragment associated chromosomal alpha-hly determinant. The relation between hemolytic phenotype and DNA hybridization pattern was found in unrelated E. coli isolates of human and animal origin. An association of alpha-hemolysin with other virulence factors was found in most strains of all three phenotypes.
当对58株大肠杆菌进行α-溶血素合成研究时，在血琼脂上检测到三种不同的溶血表型。在具有染色体编码α-hly基因的菌株中，表型I（大而清晰的溶血区）与高溶血活性以及与α-hly特异性基因探针杂交的17.2 kb大小的BamHI限制性片段相对应。表型II（小而浑浊的溶血区）与低溶血活性相关，通常与12.8 kb大小的杂交BamHI限制性片段相关。在少数具有中等溶血活性的菌株中发现了中间表型（I/II型）。在携带α-hly质粒的大肠杆菌中未发现溶血表型与活性之间的这种相关性。I型菌株在其17.2 kb大小的与染色体α-hly决定簇相关的BamHI片段的启动子区域与所有其他菌株不同。在人和动物来源的无关大肠杆菌分离株中发现了溶血表型与DNA杂交模式之间的关系。在所有三种表型的大多数菌株中都发现了α-溶血素与其他毒力因子的关联。
