Institute of Medical Microbiology, University Hospital of Münster, Münster, Germany.
Institute of Medical Microbiology, University Hospital of Münster, Münster, Germany
J Clin Microbiol. 2018 Aug 27;56(9). doi: 10.1128/JCM.00140-18. Print 2018 Sep.
Whereas the emergence of livestock-associated methicillin-resistant (LA-MRSA) clonal complex 398 (CC398) in animal husbandry and its transmission to humans are well documented, less is known about factors driving the epidemic spread of this zoonotic lineage within the human population. One factor could be the bacteriophage phi3, which is rarely detected in isolates from animals but commonly found among isolates from humans, including those of the human-adapted methicillin-susceptible (MSSA) CC398 clade. The proportion of phi3-carrying MRSA -CC011 isolates, which constitute presumptively LA-MRSA within the multilocus sequence type (MLST) clonal complex 398, was systematically assessed for a period of 16 years to investigate the role of phi3 in the adaptation process of LA-MRSA to the human host. For this purpose, 632 MRSA -CC011 isolates from patients of a university hospital located in a pig farming-dense area in Germany were analyzed. Livestock-associated acquisition of MRSA -CC011 was previously reported as having increased from 1.8% in 2000 to 29.4% in 2014 in MRSA-positive patients admitted to this hospital. However, in this study, the proportion of phi3-carrying isolates rose only from 1.1% (2000 to 2006) to 3.9% (2007 to 2015). Characterization of the phi3 genomes revealed 12 different phage types ranging in size from 40,712 kb up to 44,003 kb, with four hitherto unknown integration sites (genes or intergenic regions) and several modified bacterial attachment () sites. In contrast to the MSSA CC398 clade, phi3 acquisition seems to be no major driver for the readaptation of MRSA spa-CC011 to the human host.
尽管在畜牧业中出现了与牲畜相关的耐甲氧西林金黄色葡萄球菌（LA-MRSA）克隆复合体 398（CC398），并且其已传播给人类，但人们对该人畜共患病系在人类群体中流行传播的驱动因素知之甚少。一个因素可能是噬菌体 phi3，它在动物分离株中很少被检测到，但在人类分离株中很常见，包括人类适应的甲氧西林敏感金黄色葡萄球菌（MSSA）CC398 分支。phi3 携带的 MRSA-CC011 分离株的比例（构成假定的 LA-MRSA ）在多基因座序列型（MLST）克隆复合体 398 中，在 16 年的时间内进行了系统评估，以研究 phi3 在 LA-MRSA 适应人类宿主的过程中的作用。为此，对德国一个养猪密集地区的一家大学医院的 632 株 MRSA-CC011 患者分离株进行了分析。先前的研究报告称，该医院收治的 MRSA 阳性患者中，LA-MRSA 的获得性感染从 2000 年的 1.8%增加到 2014 年的 29.4%。然而，在这项研究中，phi3 携带分离株的比例仅从 1.1%（2000 年至 2006 年）上升至 3.9%（2007 年至 2015 年）。phi3 基因组的特征分析显示，12 种不同的噬菌体类型，大小从 40,712 kb 到 44,003 kb 不等，有四个以前未知的整合位点（基因或基因间区）和几个修饰的细菌附着位点（）。与 MSSA CC398 分支不同，phi3 的获得似乎不是 MRSA spa-CC011 重新适应人类宿主的主要驱动因素。
