Mylvaganam H, Bjorvatn B, Osland A
Department of Microbiology and Immunology, The Gade Institute, Bergen, Norway.
APMIS. 2000 Nov;108(11):771-8. doi: 10.1034/j.1600-0463.2000.d01-28.x.
In order to compare the distribution of selected virulence genes among group A streptococci recovered from invasive disease and superficial infections, 42 isolates were screened for mga, speB, speA, ssa and ska, by PCR. The isolates were predominantly of the sequence types emm1, emm3 and emm6, but also included a few of the types emm22, emm28, emm75 and emm78. The phage-mediated speA seemed to be prevalent in emm types 1 and 3, and its distribution was not related to disease severity. The other genes were present in all isolates. The mga, speB and speA were further studied by sequence analysis. Although allotypic associations with invasiveness were not found, allelic specificity to the emm sequence type was observed. In addition, the mga sequences indicated two lineages, related to opacity factor production. A possible recombination between these two main divergent mga genes was observed in isolates of the types emm22 and emm75. A logical nomenclature of the alleles of mga and speB is suggested.
为了比较从侵袭性疾病和浅表感染中分离出的A组链球菌中所选毒力基因的分布情况，通过聚合酶链反应（PCR）对42株分离株进行了mga、speB、speA、ssa和ska基因的筛选。这些分离株主要属于emm1、emm3和emm6序列类型，但也包括少数emm22、emm28、emm75和emm78类型。噬菌体介导的speA似乎在emm1型和emm3型中普遍存在，其分布与疾病严重程度无关。其他基因在所有分离株中均有存在。通过序列分析对mga、speB和speA进行了进一步研究。虽然未发现与侵袭性的异型关联，但观察到与emm序列类型的等位基因特异性。此外，mga序列表明存在两个与不透明因子产生相关的谱系。在emm22型和emm75型分离株中观察到这两个主要不同的mga基因之间可能发生了重组。建议对mga和speB的等位基因采用合理的命名法。
