González-Domínguez María, Seral Cristina, Potel Carmen, Constenla Lucía, Algarate Sonia, Gude M José, Álvarez Maximiliano, Castillo Francisco Javier
Servicio de Microbiología, Hospital Clínico Universitario Lozano Blesa, San Juan Bosco s/n, Zaragoza, Spain.
Servicio de Microbiología, Hospital Clínico Universitario Lozano Blesa y Departamento de Microbiología, Facultad de Medicina, Universidad de Zaragoza, San Juan Bosco s/n, Zaragoza, Spain.
Enferm Infecc Microbiol Clin. 2015 Nov;33(9):590-6. doi: 10.1016/j.eimc.2015.01.015. Epub 2015 Mar 4.
MRSA population dynamics is undergoing significant changes, and for this reason it is important to know which clones are circulating in our nosocomial environment.
A total of 118 MRSA isolates were collected from clinical samples from patients with previous hospital or healthcare contact (named as hospital-onset MRSA (HO-MRSA)) during a one year period. Susceptibility testing was performed by disk diffusion and microdilution. The presence of resistance genes and virulence factors were tested by PCR. All isolates were typed by SCCmec, spa and agr typing. PFGE and MLST were applied to a selection of them.
Eighty-three HO-MRSA isolates (70.3%) were resistant to any antibiotic included in the macrolide-lincosamide-streptogramin B group. Among these isolates, the M phenotype was the most frequent (73.5%). One hundred and seven of HO-MRSA isolates (90.7%) showed aminoglycoside resistance. The combination aac(6')-Ie-aph(2″)-Ia+ant(4')-Ia genes was the most frequent (22.4%). Tetracycline resistance rates in HO-MRSA isolates were low (3.4%), although a high level of mupirocin resistance was observed (25.4%). Most of the HO-MRSA isolates (approximately 90%) showed SCCmec type IVc and agr type II. Fifteen unrelated pulsotypes were identified. CC5 was the most prevalent (88.1%), followed by CC8 (5.9%), CC22 (2.5%), CC398 (2.5%) and CC1 (0.8%).
CC5/ST125/t067 lineage was the most frequent. This lineage was related to aminoglycoside resistance, and to a lesser extent, with macrolide resistance. The presence of international clones as EMRSA-15 (CC22/ST22), European clones as CC5/ST228, community clones related to CC1 or CC8 and livestock associated clones, as CC398, were observed in a low percentage.
耐甲氧西林金黄色葡萄球菌（MRSA）的种群动态正在发生重大变化，因此了解在我们的医院环境中传播的是哪些克隆株很重要。
在一年期间，从曾有过住院或医疗接触的患者的临床样本中总共收集了118株MRSA分离株（称为医院获得性MRSA（HO-MRSA））。通过纸片扩散法和微量稀释法进行药敏试验。通过聚合酶链反应（PCR）检测耐药基因和毒力因子的存在。所有分离株均通过葡萄球菌染色体盒式甲氧西林酶（SCCmec）、葡萄球菌蛋白A（spa）和群体感应调节基因（agr）分型。脉冲场凝胶电泳（PFGE）和多位点序列分型（MLST）应用于其中一部分分离株。
83株HO-MRSA分离株（70.3%）对大环内酯类-林可酰胺类-链阳菌素B组中的任何抗生素耐药。在这些分离株中，M表型最为常见（73.5%）。107株HO-MRSA分离株（90.7%）表现出氨基糖苷类耐药。aac(6')-Ie-aph(2″)-Ia+ant(4')-Ia基因组合最为常见（22.4%）。HO-MRSA分离株对四环素的耐药率较低（3.4%），尽管观察到对莫匹罗星的高水平耐药（25.4%）。大多数HO-MRSA分离株（约90%）显示为SCCmec IVc型和agr II型。鉴定出15种不相关的脉冲型。序列型5（CC5）最为普遍（88.1%），其次是CC8（5.9%）、CC22（2.5%）、CC398（2.5%）和CC1（0.8%）。
CC5/ST125/t067谱系最为常见。该谱系与氨基糖苷类耐药相关，在较小程度上与大环内酯类耐药相关。观察到国际克隆株如EMRSA-15（CC22/ST22）、欧洲克隆株如CC5/ST228、与CC1或CC8相关的社区克隆株以及与牲畜相关的克隆株如CC398的比例较低。
