Department of Microbiology and Immunology, Faculty of pharmacy, Delta University for Science and Technology, Gamasa, Egypt.
Department of Pharmaceutical Microbiology, Faculty of Pharmacy, Tanta University, Tanta, Egypt.
BMC Microbiol. 2023 Oct 28;23(1):315. doi: 10.1186/s12866-023-03065-8.
Methicillin-resistant Staphylococcus aureus is linked to both nosocomial and community infections. One of the key virulence factors of S. aureus is Panton-Valentine leukocidin (PVL). The PVL genes are mostly associated with community-acquired MRSA (CA-MRSA). This study evaluates the prevalence of PVL genes as a marker for CA-MRSA at tertiary hospitals in Mansoura, Dakahlia, Egypt. S. aureus was isolated from clinical specimens obtained from different departments of tertiary hospitals, outpatient clinics, and hospital healthcare workers (HCWs). PCR was used to detect the mecA, PVL, and SCCmec genes among the recovered isolates. Standard broth microdilution method was used to determine the minimum inhibitory concentrations (MIC) of nine antibiotics against S. aureus.
Two hundred S. aureus isolates were recovered and identified out of the total isolates (n = 320). The mecA gene was detected in 103 S. aureus isolates (51.5%). Among the MRSA isolates, 46.60% were PVL-positive. The incidence of the PVL genes of MRSA in nosocomial (HA), outpatient clinics (CA), and HCWs was 46.66%, 56.52%, and 42%, respectively. All MRSA isolates showed resistance to cefoxitin. The percentage of resistance to most tested antibiotics was high, except for ciprofloxacin (6.85%). Both antibiotic resistance and multidrug resistance among MRSA isolates were generally higher in PVL-positive isolates than in PVL-negative isolates in HA- and CA-MRSA isolates. While SCCmec type V was the most prevalent in PVL-positive MRSA stains, type I was the most prevalent in PVL-negative isolates.
This study revealed that PVL genes are generally highly prevalent among mecA-positive MRSA isolates, whether they are CA-MRSA, HA-MRSA, or HCW isolates. Therefore, PVL is not a valid marker for CA-MRSA in Mansoura, Dakahlia Governorate, Egypt, as has been reported in other countries. Further epidemiologic studies are required to track the incidence of PVL in HA-MRSA, CA-MRSA, and HCW isolates in other Egyptian governorates.
耐甲氧西林金黄色葡萄球菌与医院内和社区感染均有关。金黄色葡萄球菌的一个关键毒力因子是杀白细胞素（PVL）。PVL 基因主要与社区获得性耐甲氧西林金黄色葡萄球菌（CA-MRSA）相关。本研究评估了 PVL 基因作为埃及曼苏拉代盖拉里亚省三所三级医院 CA-MRSA 标志物的流行情况。从三所三级医院的不同科室、门诊和医院医护人员（HCW）的临床标本中分离出金黄色葡萄球菌。采用聚合酶链反应（PCR）检测回收分离株中的 mecA、PVL 和 SCCmec 基因。采用肉汤微量稀释法测定金黄色葡萄球菌对 9 种抗生素的最小抑菌浓度（MIC）。
从 320 份总分离株中分离并鉴定出 200 株金黄色葡萄球菌。103 株金黄色葡萄球菌（51.5%）检测到 mecA 基因。MRSA 分离株中 46.60%为 PVL 阳性。医院获得性（HA）、门诊（CA）和 HCW 中 MRSA 分离株的 PVL 基因发生率分别为 46.66%、56.52%和 42%。所有 MRSA 分离株均对头孢西丁耐药。除环丙沙星（6.85%）外，大多数检测抗生素的耐药率均较高。在 HA-MRSA 和 CA-MRSA 分离株中，PVL 阳性的 MRSA 分离株的抗生素耐药性和多重耐药性一般高于 PVL 阴性的分离株。而在 PVL 阳性的 MRSA 菌株中，SCCmec 类型 V 最为普遍，而在 PVL 阴性的菌株中，SCCmec 类型 I 最为普遍。
本研究表明，PVL 基因在 mecA 阳性的 MRSA 分离株中普遍高度流行，无论其为 CA-MRSA、HA-MRSA 还是 HCW 分离株。因此，PVL 并非埃及曼苏拉代盖拉里亚省的 CA-MRSA 有效标志物，这与其他国家的报道不同。需要进一步的流行病学研究来跟踪其他埃及省份 HA-MRSA、CA-MRSA 和 HCW 分离株中 PVL 的发生率。
