Microbiology Research Unit, Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Dublin, Ireland.
National MRSA Reference Laboratory, St. James's Hospital, Dublin, Ireland.
Eur J Clin Microbiol Infect Dis. 2019 May;38(5):927-936. doi: 10.1007/s10096-019-03523-0. Epub 2019 Mar 23.
The prevalence of methicillin-susceptible Staphylococcus aureus (MSSA) bloodstream infections (BSIs) has increased in many countries, including Ireland. This study aimed to investigate the molecular epidemiology of MSSA causing BSIs in Irish hospitals between 2006 and 2017, when MSSA BSIs increased, to identify any potential patient or pathogen contributing factors. A total of 252 MSSA isolates from patients in Irish hospitals in 2006/2007, 2011 and 2017 underwent spa typing and DNA microarray profiling. Each patient's gender, age, 14-day mortality and epidemiological context of infection were recorded. Significant increases in community-onset (CO) MSSA BSIs and the average patient's age and decreases in hospital-onset (HO) MSSA were identified. Although, extensive genetic diversity was detected amongst the isolates, i.e. 24 multilocus sequence type clonal complexes (CCs)/sequence types and 124 spa types, three CCs (CC30, CC45, CC5) dominated, albeit in different proportions, during the study periods. CC30 declined significantly, in particular spa type t021, and was more common amongst HO-MSSA and CC45 and CC8 increased, particularly spa types t015 and t008, respectively, and were more common amongst CO-MSSA. Five of the seven most frequent spa types were more common amongst CO-MSSA. Although overall multidrug resistance decreased, the prevalence of erm(C) increased significantly and virulence genes decreased, mostly notably egc, tst, scn, sep and fnbB. This study highlights the threat posed by the increasing prevalence of CO-MSSA BSIs and suggests an association with the increasing prevalence of CC45 CO-MSSA, decreasing prevalence of CC30 HO-MSSA, an ageing population and an overall decrease in virulence and resistance genes.
耐甲氧西林金黄色葡萄球菌（MSSA）血流感染（BSI）在许多国家（包括爱尔兰）的流行率有所增加。本研究旨在调查 2006 年至 2017 年期间爱尔兰医院中导致 MSSA BSI 的 MSSA 的分子流行病学，以确定任何潜在的患者或病原体的促成因素。对 2006/2007 年、2011 年和 2017 年爱尔兰医院的 252 株 MSSA 分离株进行 spa 分型和 DNA 微阵列分析。记录每位患者的性别、年龄、14 天死亡率和感染的流行病学背景。确定社区获得性（CO）MSSA BSI 的显著增加以及平均患者年龄的降低和医院获得性（HO）MSSA 的减少。尽管分离株中存在广泛的遗传多样性，即 24 个多位点序列型克隆复合物（CC）/序列型和 124 个 spa 型，但在研究期间，三个 CC（CC30、CC45、CC5）占主导地位，尽管比例不同。CC30 显著下降，特别是 spa 型 t021，并且更常见于 HO-MSSA，而 CC45 和 CC8 增加，特别是 spa 型 t015 和 t008，并且更常见于 CO-MSSA。七种最常见的 spa 型中有五种更常见于 CO-MSSA。尽管总体而言，多药耐药性降低，但 erm(C)的流行率显著增加，毒力基因减少，特别是 egc、tst、scn、sep 和 fnbB。本研究强调了 CO-MSSA BSI 流行率增加所带来的威胁，并表明这与 CC45 CO-MSSA 流行率的增加、CC30 HO-MSSA 流行率的降低、人口老龄化以及毒力和耐药基因的总体减少有关。
