Pozzi G, Oggioni M R, Tomasz A
Laboratory of Microbiology, Rockefeller University, New York, New York 10021.
J Clin Microbiol. 1989 Feb;27(2):370-2. doi: 10.1128/jcm.27.2.370-372.1989.
A total of 287 clinical isolates of Streptococcus pneumoniae (pneumococcus) were tested for their ability to undergo autolysis when treated with sodium deoxycholate. The test was positive for all but one isolate, strain DOC-1. This autolysis required the activity of an enzyme which is unique and characteristic of S. pneumoniae: a choline-dependent N-acetylmuramoyl-L-alanine amidase, the gene product of the lytA gene. We used lytA as a DNA probe to test the distribution of the autolysin gene among clinical isolates of S. pneumoniae. In dot blot hybridization experiments our probe reacted with the DNA of 60 of 60 strains tested, including the autolysis-deficient clinical isolate DOC-1. No hybridization occurred when strains of Streptococcus sanguis, Streptococcus mutans, Streptococcus pyogenes, Streptococcus (Enterococcus) faecalis, Streptococcus (Enterococcus) faecium, Streptococcus agalactiae, and Streptococcus bovis were tested. The lytA gene appears to be an ideal candidate for use as a DNA probe for the identification of S. pneumoniae.
总共对287株肺炎链球菌（肺炎球菌）临床分离株进行了检测，以观察它们在用脱氧胆酸钠处理时发生自溶的能力。除了一株分离株DOC-1外，所有检测均呈阳性。这种自溶需要一种肺炎链球菌特有的酶的活性：一种胆碱依赖性N-乙酰胞壁酰-L-丙氨酸酰胺酶，即lytA基因的产物。我们使用lytA作为DNA探针来检测自溶素基因在肺炎链球菌临床分离株中的分布。在斑点印迹杂交实验中，我们的探针与所检测的60株菌株中的60株的DNA发生反应，包括自溶缺陷型临床分离株DOC-1。当检测血链球菌、变形链球菌、化脓性链球菌、粪肠球菌、屎肠球菌、无乳链球菌和牛链球菌的菌株时，未发生杂交。lytA基因似乎是用作鉴定肺炎链球菌的DNA探针的理想候选物。
