VIRULENCE OF STAPHYLOCOCCUS-AUREUS IN A MOUSE MASTITIS MODEL - STUDIES OF ALPHA-HEMOLYSIN, COAGULASE, AND PROTEIN-A AS POSSIBLE VIRULENCE DETERMINANTS WITH PROTOPLAST FUSION AND GENE CLONING
VIRULENCE OF STAPHYLOCOCCUS-AUREUS IN A MOUSE MASTITIS MODEL - STUDIES OF ALPHA-HEMOLYSIN, COAGULASE, AND PROTEIN-A AS POSSIBLE VIRULENCE DETERMINANTS WITH PROTOPLAST FUSION AND GENE CLONING
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DOI：
10.1128/iai.49.3.765-769.1985
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发表时间：
1985-01-01
影响因子：
3.1
通讯作者：
WADSTROM, T
中科院分区：
文献类型：
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作者：
JONSSON, P;LINDBERG, M;WADSTROM, T
经诱变后，分离到一株遗传特征良好的金黄色葡萄球菌[SA113(83A)]的突变株。对α-溶血素(Hla)、凝固酶-(CoA)和蛋白A-(SpA)阴性突变株进行了90多项产生胞外蛋白的生化试验和排除多效性的生化分析。然后用原生质体融合分离出双缺陷重组子(H1a和CoA)和恢复性质的重组子，即产生α-溶血素和凝固酶。对小鼠乳房炎模型的突变体和重组体的研究表明，1株α-溶血素[SA113(83A)HLA-5]和1株凝固酶阴性突变体[SA113(83A)CoA-147]的毒力低于野生型菌株SA113(83A)。双阴性突变体SA113(83A)HL A-5 CoA-147的致病力急剧下降，仅引起非常轻微的变化，通过对感染乳腺组织的显微镜检查确定。然而，重新获得特性的重组菌株与野生型菌株的毒力一样强。这表明α-溶血素和凝固酶是金黄色葡萄球菌毒力的决定因素。在该模型中，一个高水平的蛋白A产生突变株(U300)表现出与亲本菌株SA113(83A)相同的毒力。一个低毒力蛋白A阴性突变体(U320)将含有A蛋白基因克隆的质粒(PSPA15)导入该突变体后，其毒力没有明显提高。根据这些和早期的观察，蛋白A似乎不是小鼠乳房炎的一个重要的毒力决定因素。与野生型SA113(83A)相比，A蛋白阴性突变体U320的毒力降低可能是由于其他未知毒力决定簇(S)的多效性丢失所致。我们的数据证实了早期的发现，即多营养性变化在蛋白A阴性突变体中很常见。
Mutants of a genetically well-characterized strain of Staphylococcus aureus [SA113(83A)] were isolated after mutagenization. Alpha-hemolysin- (hla), coagulase- (coa), and protein A- (spa) negative mutants were characterized by more than 90 biochemical tests for production of extracellular proteins and biochemical profile to exclude pleiotropy. Protoplast fusion was then used to isolate double-defective (hla and coa) recombinants and recombinants with regained properties, i.e., production of alpha-hemolysin and coagulase. Studies of such mutants and recombinants of the mouse mastitis model showed that one alpha-hemolysin [SA113(83A) hla-5] and one coagulase-negative [SA113(83A) coa-147] mutant were lower in virulence compared with the wild-type strain SA113(83A). The double-negative mutant SA113(83A) hla-5 coa-147 showed a drastic decline in virulence and only induced very mild changes, as determined by microscopic examinations of infected mammary gland tissue. The recombinant with regained properties, however, was as virulent as the wild-type strain. This suggests that alpha-hemolysin and coagulase are virulence determinants of S. aureus. A high-level protein A-producing mutant (U300) showed the same virulence as the parent strain SA113(83A) in this model. One low virulence protein A-negative mutant (U320) did not markedly increase in virulence when a plasmid containing the cloned gene for protein A (pSPA15) was introduced into this mutant. By these and earlier observations, it seems likely that protein A is not an important virulence determinant in mastitis of mice. The reduced virulence of the protein A-negative mutant U320 compared with the wild-type SA113(83A) may be due to pleiotropic loss of some other unknown virulence determinant(s). Our data confirm earlier findings that pleiotrophic changes are common in protein A-negative mutants.