Galán-Sánchez Fátima, Pérez-Eslava Maria, Machuca Jesús, Trujillo-Soto Teresa, Arca-Suarez Jorge, Rodríguez-Iglesias Manuel
UGC Microbiología, Hospital Universitario Puerta del Mar, Cádiz, Spain.
Centro de Salud Barrio Bajo, Arcos de la Frontera, Cádiz, Spain.
Enferm Infecc Microbiol Clin (Engl Ed). 2019 Mar;37(3):172-175. doi: 10.1016/j.eimc.2018.05.011. Epub 2018 Jun 20.
The epidemiology of S. aureus depends on conditions in specific populations. Few studies of S. aureus colonization in the older population have been performed in Spain. The aim of this study was to determine the prevalence of methicillin-resistant S. aureus (MRSA) colonization and its molecular epidemiological characteristics in an institutionalized population in community residential care homes in Cadiz, Spain.
A cross-sectional epidemiological study was conducted in three residential care homes for older people. Axilla and nostril samples were tested. Identification of S. aureus and antimicrobial susceptibility testing were by MALDI-TOF and MicroScan panels. MRSA strains were subjected to SCCmec typing, multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE). The presence of Panton-Valentine leukocidin (PVL) genes was determined by PCR in all S. aureus strains.
A total of 293 residents were included. Fifty-one residents (17.4%) were colonized with methicillin-sensitive S. aureus (MSSA) and 11 (3.8%) with MRSA. Resistance to at least two aminoglycosides was observed in 25.4% of MSSA and 90.9% and of MRSA isolates, and resistance to levofloxacin in 80.3% of MSSA and 100% of MRSA isolates. SCCmecIV was detected in all isolates and all except one (ST-125) were ST-8. None of the S. aureus isolates were positive for PVL.
A low rate of S. aureus carriage was detected and the prevalence of MRSA was very low. ST8-MRSA-IVc was the dominant clone, and only one strain belonged to ST125-MRSA-IVc. We found MRSA transmission within the residential care homes and a very high rate of quinolone resistance in MSSA and MRSA.
金黄色葡萄球菌的流行病学情况取决于特定人群的状况。在西班牙，针对老年人群中金黄色葡萄球菌定植情况的研究较少。本研究的目的是确定西班牙加的斯社区养老院中机构化人群耐甲氧西林金黄色葡萄球菌（MRSA）定植的患病率及其分子流行病学特征。
在三家老年养老院开展了一项横断面流行病学研究。采集腋窝和鼻孔样本进行检测。通过基质辅助激光解吸电离飞行时间质谱（MALDI-TOF）和MicroScan鉴定板对金黄色葡萄球菌进行鉴定并进行药敏试验。对MRSA菌株进行葡萄球菌染色体盒式甲氧西林酶（SCCmec）分型、多位点序列分型（MLST）和脉冲场凝胶电泳（PFGE）。通过聚合酶链反应（PCR）检测所有金黄色葡萄球菌菌株中是否存在杀白细胞素（PVL）基因。
共纳入293名居民。51名居民（17.4%）被甲氧西林敏感金黄色葡萄球菌（MSSA）定植，11名居民（3.8%）被MRSA定植。25.4%的MSSA分离株和90.9%的MRSA分离株对至少两种氨基糖苷类药物耐药，80.3%的MSSA分离株和100%的MRSA分离株对左氧氟沙星耐药。在所有分离株中均检测到SCCmecIV，除一株（ST-125）外，其余均为ST-8型。所有金黄色葡萄球菌分离株的PVL检测均为阴性。
检测到的金黄色葡萄球菌携带率较低，MRSA的患病率非常低。ST8-MRSA-IVc是主要克隆型，仅一株属于ST125-MRSA-IVc。我们发现养老院内部存在MRSA传播，且MSSA和MRSA对喹诺酮类药物的耐药率非常高。
