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Abstract：
BACKGROUND: Peritonitis is the most important complication of peritoneal dialysis (PD) and coagulase-negative staphylococci (CNS) are a frequent cause of dialysis-related infections. The association between SCCmec typing with psm-mec positivity in staphylococci and PD-related infections has not been identified. We aim to investigate the molecular epidemiology of CNS isolated from PD-peritonitis in a single Chinese center, focusing on the genetic determinants conferring methicillin resistance.
METHODS: We collected 10 genetically unrelated CNS isolates from 10 patients with CNS PD-related peritonitis. The patients were divided into two groups based on the results of MIC to oxacillin: the methicillin-resistant CNS (MRCNS) and methicillin-sensitive CNS (MSCNS) groups. The biofilm formation group (BFG) and the non-biofilm formation group (NBFG) were used as the control groups. Phenotypic and molecular methods were used to analyze SCCmec types I, II and III, associated genes and biofilm formation and the existence of psm-mec. The demographic data and clinical indicators were collected.
RESULTS: Ten CNS PD-related peritonitis patients were enrolled for this study. There were 6 MRCNS and 4 MRCNS isolates. SCCmec types were fully determined in 10 isolates. Seven staphylococci (70%) carried SCCmec, of which 4 isolates carried single SCCmec type I (40%) and 3 isolates had multiple SCCmec elements (I + III). Of the 6 MRCNS isolates, 3 carried SCCmec type I (50%) and 2 isolates carried SCCmec type I + III (33.3%). A high diversity of ccr types, mec complexes and ccr-mec complex combinations was identified among the 10 CNS isolates. The psm-mec gene was detected in 2/10 (20%) CNS isolates. There was no mutation in the psm-mec gene.
CONCLUSIONS: The majority of isolates were hospital-associated isolates. Furthermore, 2 psm-mec positive isolates were MRCNS in the NBFG. The PD patients frequent exposure to hospital would be the main risk factor. The presence of the psm-mec signal in the spectra of the MRCNS tested here demonstrates the presence of certain SCCmec cassettes that convey methicillin resistance.
METHODS: We collected 10 genetically unrelated CNS isolates from 10 patients with CNS PD-related peritonitis. The patients were divided into two groups based on the results of MIC to oxacillin: the methicillin-resistant CNS (MRCNS) and methicillin-sensitive CNS (MSCNS) groups. The biofilm formation group (BFG) and the non-biofilm formation group (NBFG) were used as the control groups. Phenotypic and molecular methods were used to analyze SCCmec types I, II and III, associated genes and biofilm formation and the existence of psm-mec. The demographic data and clinical indicators were collected.
RESULTS: Ten CNS PD-related peritonitis patients were enrolled for this study. There were 6 MRCNS and 4 MRCNS isolates. SCCmec types were fully determined in 10 isolates. Seven staphylococci (70%) carried SCCmec, of which 4 isolates carried single SCCmec type I (40%) and 3 isolates had multiple SCCmec elements (I + III). Of the 6 MRCNS isolates, 3 carried SCCmec type I (50%) and 2 isolates carried SCCmec type I + III (33.3%). A high diversity of ccr types, mec complexes and ccr-mec complex combinations was identified among the 10 CNS isolates. The psm-mec gene was detected in 2/10 (20%) CNS isolates. There was no mutation in the psm-mec gene.
CONCLUSIONS: The majority of isolates were hospital-associated isolates. Furthermore, 2 psm-mec positive isolates were MRCNS in the NBFG. The PD patients frequent exposure to hospital would be the main risk factor. The presence of the psm-mec signal in the spectra of the MRCNS tested here demonstrates the presence of certain SCCmec cassettes that convey methicillin resistance.
摘要：
背景：腹膜炎是腹膜透析（PD）最重要的并发症，而凝固酶阴性葡萄球菌（CNS）是透析相关感染的常见原因。尚未确定SCCmec分型与葡萄球菌psm-mec阳性和PD相关感染之间的关联。我们的目的是调查单个中国中心从PD-腹膜炎中分离出的CNS的分子流行病学。关注赋予甲氧西林抗性的遗传决定因素。
方法：我们从10例中枢神经系统PD相关性腹膜炎患者中收集了10例遗传无关的中枢神经系统分离株。根据对苯唑西林的MIC结果，将患者分为两组：耐甲氧西林CNS（MRCNS）和对甲氧西林敏感的CNS（MSCNS）组。以生物膜形成组(BFG)和非生物膜形成组(NBFG)作为对照组。表型和分子方法用于分析SCCmecI型，II和III,相关基因和生物膜的形成以及psm-mec的存在。收集人口统计学数据和临床指标。
结果：10例中枢神经系统PD相关性腹膜炎患者纳入本研究。有6个MRCNS和4个MRCNS分离物。在10个分离株中完全确定了SCCmec类型。七个葡萄球菌（70％）携带SCCmec，其中4个分离株携带单个SCCmecI型（40％），3个分离株具有多个SCCmec元素（IIII）。在6个MRCNS分离物中，3株携带SCCmecI型(50%)，2株携带SCCmecI+III型(33.3%)。CCR类型的高度多样性，在10个CNS分离株中鉴定了mec复合物和ccr-mec复合物组合。在2/10(20%)CNS分离物中检测到psm-mec基因。psm-mec基因没有突变。
结论：大多数分离株是医院相关分离株。此外，2个psm-mec阳性分离株是NBFG中的MRCNS。PD患者频繁住院是其主要危险因素。此处测试的MRCNS的光谱中psm-mec信号的存在证明了某些传递甲氧西林抗性的SCCmec盒的存在。
方法：我们从10例中枢神经系统PD相关性腹膜炎患者中收集了10例遗传无关的中枢神经系统分离株。根据对苯唑西林的MIC结果，将患者分为两组：耐甲氧西林CNS（MRCNS）和对甲氧西林敏感的CNS（MSCNS）组。以生物膜形成组(BFG)和非生物膜形成组(NBFG)作为对照组。表型和分子方法用于分析SCCmecI型，II和III,相关基因和生物膜的形成以及psm-mec的存在。收集人口统计学数据和临床指标。
结果：10例中枢神经系统PD相关性腹膜炎患者纳入本研究。有6个MRCNS和4个MRCNS分离物。在10个分离株中完全确定了SCCmec类型。七个葡萄球菌（70％）携带SCCmec，其中4个分离株携带单个SCCmecI型（40％），3个分离株具有多个SCCmec元素（IIII）。在6个MRCNS分离物中，3株携带SCCmecI型(50%)，2株携带SCCmecI+III型(33.3%)。CCR类型的高度多样性，在10个CNS分离株中鉴定了mec复合物和ccr-mec复合物组合。在2/10(20%)CNS分离物中检测到psm-mec基因。psm-mec基因没有突变。
结论：大多数分离株是医院相关分离株。此外，2个psm-mec阳性分离株是NBFG中的MRCNS。PD患者频繁住院是其主要危险因素。此处测试的MRCNS的光谱中psm-mec信号的存在证明了某些传递甲氧西林抗性的SCCmec盒的存在。
