Division of Infectious Diseases and International Health, University of Virginia Health System, Charlottesville, VA, USA.
Virulence. 2012 Nov 15;3(7):576-82. doi: 10.4161/viru.22120. Epub 2012 Oct 17.
Community-associated (CA) methicillin-resistant Staphylococcus aureus (MRSA) strains have emerged as major human pathogens. CA-MRSA virulence appears to be distinct from healthcare-associated (HA) MRSA with several factors [α-hemolysin (Hla), Panton-Valentine leukocidin (PVL), α-type phenol soluble modulins (PSMα) and SCCmec IV] postulated to enhance virulence or fitness. Using the Caenorhabditis elegans infection model, we compared the virulence of clinical and laboratory isolates of CA-MRSA and HA-MRSA and explored the contribution of CA-MRSA associated virulence factors to nematode killing. All CA-MRSA strains were highly pathogenic to nematodes, while HA-MRSA strains demonstrated variable nematode killing. Nematode killing by isogenic mutants of hla or the loci for PVL, PSMα, PSMβ, PSMδ or SCCmec IV was not different than the parental strains. These results demonstrate that CA-MRSA is highly virulent, shows some strains of HA-MRSA are equally virulent toward nematodes and suggests CA-MRSA virulence in C. elegans is not linked to a single virulence factor.
社区获得性（CA）耐甲氧西林金黄色葡萄球菌（MRSA）菌株已成为主要的人类病原体。CA-MRSA 的毒力似乎与与医疗保健相关（HA）MRSA 不同，有几个因素[α-溶血素（Hla）、金葡素（PVL）、α 型酚可溶性调节素（PSMα）和 SCCmec IV]被认为增强了毒力或适应性。我们使用秀丽隐杆线虫感染模型，比较了临床和实验室分离的 CA-MRSA 和 HA-MRSA 的毒力，并探讨了 CA-MRSA 相关毒力因子对线虫杀伤的贡献。所有 CA-MRSA 菌株对线虫均具有高度致病性，而 HA-MRSA 菌株对线虫的杀伤能力则存在差异。hla 或 PVL、PSMα、PSMβ、PSMδ 或 SCCmec IV 基因座的异源突变体与亲本菌株相比，对线虫的杀伤能力没有差异。这些结果表明，CA-MRSA 具有高度的致病性，表明一些 HA-MRSA 菌株对线虫的致病性相当，并且提示 CA-MRSA 在秀丽隐杆线虫中的毒力与单个毒力因子无关。
