Objective. Methicillin-resistant Staphylococcus aureus (MRSA) is one of the main causative agents of nosocomial infections that has posed a major threat to those with compromised immune systems such as nursing home residents. The aim of this study was to determine the rates of MRSA strains and the types of Staphylococcal Cassette Chromosome mec (SCCmec)in nursing homes in Saudi Arabia. Methods. A total of 188 nasal swabs were collected from the residents and nursing staff in two nursing homes in Riyadh, Saudi Arabia. All MRSA isolates were tested for antimicrobial susceptibility and analyzed for mecA and SCCmec typing by multiplex PCR assay. Detection of the Panton–Valentine leukocidin (PVL) gene was also tested in all positive MRSA isolates by multiplex PCR using specific primers. Results. Among the 188 collected nasal swabs (105 males and 83 females), MRSA colonization rate was 9.04% (11 (5.85%) females and 6 (5.71%) males). About 47% of MRSA were multidrug resistant (MDR) as acquired resistance to beta-lactam, macrolide, and aminoglycoside antibiotics. However, all the MRSA isolates showed susceptibility to vancomycin, tigecycline, and linezolid. All the MRSA isolates (n = 17) were mecA-positive with the SCCmec IVc (n = 7, 41.18%) as the most common SCCmec type followed by SCCmec V (n = 5, 29.41%) and SCCmec IVa (n = 2, 11.76%). The remaining isolates (n = 3) were nontypeable (17.65%). In addition, the PVL toxin gene was only detected in four of the male samples. Conclusion. MRSA nasal colonization is a common incident among nursing home residents. The prevalence of community-associated (CA) MRSA (SCCmec IV and V) was more common than hospital-associated (HA) MRSA in our study samples. It is crucial to investigate such rate of incidence, which is a key tool in preventive medicine and would aid in determining health policy and predict emergent outbreaks.

中文翻译：

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沙特阿拉伯疗养院中耐甲氧西林金黄色葡萄球菌定植的患病率和分子遗传学。

客观。耐甲氧西林金黄色葡萄球菌(MRSA) 是医院感染的主要病原体之一，对免疫系统受损的人（如疗养院居民）构成重大威胁。本研究的目的是确定沙特阿拉伯疗养院中 MRSA 菌株的比率和葡萄球菌盒式染色体 mec (SCCmec ) 的类型。方法。从沙特阿拉伯利雅得的两家疗养院的居民和护理人员那里共采集了 188 份鼻拭子。所有 MRSA 分离株都进行了抗菌敏感性测试，并通过多重 PCR 分析分析了mecA和SCCmec分型。Panton-Valentine leukocidin 的检测（还使用特异性引物通过多重 PCR 在所有阳性 MRSA 分离物中测试了PVL ) 基因。结果。在采集的188份鼻拭子中（男性105例，女性83例），MRSA定植率为9.04%（女性11例（5.85%），男性6例（5.71%））。大约 47% 的 MRSA 对 β-内酰胺、大环内酯类和氨基糖苷类抗生素具有获得性耐药性（MDR）。然而，所有 MRSA 分离株都对万古霉素、替加环素和利奈唑胺表现出敏感性。所有 MRSA 分离株 ( n  = 17) 均为mecA阳性，其中 SCC mec IVc ( n  = 7, 41.18%) 是最常见的 SCC mec类型，其次是 SCC mec V ( n = 5, 29.41%) 和 SCC mec IVa ( n  = 2, 11.76%)。其余分离株 ( n  = 3) 不可分型 (17.65%)。此外，仅在四个男性样本中检测到 PVL 毒素基因。结论。MRSA 鼻腔定植是疗养院居民中的常见事件。在我们的研究样本中，社区相关 (CA) MRSA（SCC mec IV 和 V）的患病率比医院相关 (HA) MRSA 更常见。调查这种发病率至关重要，这是预防医学的关键工具，有助于确定卫生政策和预测突发事件。