Epidemic MRSA clone ST22-IV is more resistant to multiple host-and environment-related stresses compared with ST228-I
Epidemic MRSA clone ST22-IV is more resistant to multiple host-and environment-related stresses compared with ST228-I
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DOI：
10.1093/jac/dku467
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发表时间：
2015-03-01
影响因子：
5.2
通讯作者：
Cirillo, Daniela Maria
中科院分区：
文献类型：
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作者：
Baldan, Rossella;Rancoita, Paola Maria Vittoria;Cirillo, Daniela Maria
背景：ST22-IV 是一个成功的医院相关 MRSA 克隆。由于其已知能够替代医院中的其他 MRSA 克隆，因此它成为欧洲及其他地区的主要克隆。迄今为止，还没有研究调查MRSA克隆的流行病学成功与它们承受常见应激能力之间的关系。方法：我们研究了ST22-IV与替代克隆ST228-I的适应性，评估其对氧化应激的抵抗力、自溶活性、在高渗透压和酸碱环境下的生长以及在干燥和热休克下的存活。我们还比较了它们的表型特征，并检查了抗生素消耗对流行病学成功的影响。结果：在这里，我们证明 ST22-IV 的优势既与抗生素消耗的变化无关，也与随着时间的推移获得额外的耐药性无关。强烈的α-溶血素活性、β-溶血素的产生以及活性agr的存在可以部分解释先前在小鼠肺炎模型中观察到的ST22-IV的毒力。最重要的是，我们表明，与 ST228-I 相比，ST22-IV 除了随着时间的推移保留对大多数抗生素的敏感性外，在所有测试的压力条件下（细菌在其生命周期中通常面临的压力条件下）具有优越的生存能力。结论：我们的结果支持我们的假设，即 ST22-IV 比 ST228-I 具有适应性优势。这种适应性优势可能使 ST22-IV 能够取代 ST228-I，而不会产生额外的耐药性，并有助于解释其在医院环境中的流行及其在欧洲及其他地区的传播。
Background: ST22-IV is a successful hospital-associated MRSA clone. Due to its known ability to replace other MRSA clones in hospitals, it became a dominant clone in Europe and beyond. So far, there are no studies investigating the relationship between the epidemiological success of MRSA clones and their capacity to withstand commonly encountered stresses.Methods: We investigated the fitness of ST22-IV in comparison with the replaced clone ST228-I, evaluating its resistance to oxidative stress, autolytic activity, growth at high osmolarity and in acid and alkaline environments and survival under desiccation and heat shock. We also compared their phenotypic characteristics and examined the impact of antibiotic consumption on epidemiological success.Results: Here we demonstrate that the dominance of ST22-IV is linked neither to changes in antibiotic consumption nor to acquisition of additional resistances over time. Strong a-haemolysin activity, the production of beta-haemolysin and the presence of an active agr could partly explain the virulence of ST22-IV previously observed in a murine model of pneumonia. Most importantly, we show that ST22-IV compared with ST228-I, besides retaining susceptibility to most antibiotics over time, has a superior capacity to survive under all stress conditions tested, which bacteria commonly face during their life cycle.Conclusions: Our results support our hypothesis that ST22-IV has a fitness advantage over ST228-I. This fitness advantage could have allowed ST22-IV to displace ST228-I without acquiring additional resistances and could help explain its epidemic success in hospital settings and its spread in Europe and beyond.