Tyler S D, Johnson W M, Huang J C, Ashton F E, Wang G, Low D E, Rozee K R
Bureau of Microbiology, Laboratory Centre for Disease Control, Ottawa, Ontario, Canada.
J Clin Microbiol. 1992 Dec;30(12):3127-31. doi: 10.1128/jcm.30.12.3127-3131.1992.
The presence of genes encoding pyrogenic exotoxins type A (speA), B (speB), and C (speC) and streptolysin O (slo) was determined by the polymerase chain reaction (PCR) to target specific sequences in 152 strains of group A streptococci. These included reference strains, representative M and T type strains, and strains associated with scarlet fever and pharyngitis collected between 1940 to 1991 and included strains from patients with severe invasive streptococcal infections. PCR amplicons were detected by agarose gel electrophoresis, and specificity was established by restriction fragment analysis. The frequency of occurrence for each target gene among all strains tested was 33.6% for speA, 99.3% for speB, 28.9% for speC, and 100% for slo. Strains of non-group A streptococci, recognized toxigenic bacterial pathogens, and pneumolysin-producing Streptococcus pneumoniae strains were negative for all targeted gene sequences. Detection limits in the PCR were found to be 100 pg of total nucleic acids for the speB and speC genes and 1 ng for the speA and slo genes. Isolates associated with scarlet fever, pharyngitis, and severe invasive infections showed statistically significant differences in the presence of speA, with scarlet fever strains having the highest association (81.3%), severe infections the next highest association (42.9%), and pharyngitis the lowest association (18.4%). Although no significant differences were observed in speC frequencies in isolated associated with the three disease categories, a genotype of speB slo was significantly higher in isolates associated with pharyngitis (54.1%) than in strains associated with scarlet fever (18.8%) or severe invasive disease (23.8%). Streptolysin O targets were present in all the isolates tested, and only a single strain (T-11-M-11) was devoid of targeted speB sequences, thereby demonstrating that neither speB nor slo is associated with any particular clinical presentation.
采用聚合酶链反应（PCR）检测152株A群链球菌中编码A型（speA）、B型（speB）和C型（speC）致热外毒素及链球菌溶血素O（slo）的基因，以靶向特定序列。这些菌株包括参考菌株、具有代表性的M和T型菌株，以及1940年至1991年间收集的与猩红热和咽炎相关的菌株，还包括来自严重侵袭性链球菌感染患者的菌株。通过琼脂糖凝胶电泳检测PCR扩增产物，并通过限制性片段分析确定其特异性。在所检测的所有菌株中，每个目标基因的出现频率分别为：speA为33.6%，speB为99.3%，speC为28.9%，slo为100%。非A群链球菌菌株、公认的产毒细菌病原体以及产肺炎溶血素的肺炎链球菌菌株的所有靶向基因序列均为阴性。发现PCR对speB和speC基因的检测限为总核酸100 pg，对speA和slo基因的检测限为1 ng。与猩红热、咽炎和严重侵袭性感染相关的分离株在speA的存在情况上显示出统计学显著差异，其中猩红热菌株的相关性最高（81.3%），严重感染菌株次之（42.9%），咽炎菌株最低（18.4%）。尽管在与这三种疾病类别相关的分离株中speC频率未观察到显著差异，但与咽炎相关的分离株中speB slo基因型（54.1%）显著高于与猩红热相关的菌株（18.8%）或严重侵袭性疾病相关的菌株（23.8%）。在所检测的所有分离株中均存在链球菌溶血素O靶点，只有一个菌株（T - 11 - M - 11）缺乏靶向的speB序列，从而表明speB和slo均与任何特定临床表现无关。
