Department of Microbiology, University of Health Sciences, Lahore, Punjab, Pakistan.
Department of Microbiology, University of Health Sciences, Lahore, Punjab, Pakistan.
Am J Infect Control. 2023 Feb;51(2):178-183. doi: 10.1016/j.ajic.2022.05.018. Epub 2022 May 27.
Staphylococcus aureus is a nosocomial pathogen, detection and elucidation of its resistance mechanisms to conventional disinfectants may aid in limiting its spread on environmental surfaces in health care settings. In the current study, disinfectant susceptibility of S. aureus strains isolated from the hospital environment as well as possible associations between the presence of disinfectant-resistance genes and reduced susceptibility to disinfectants was investigated.
A total of 245 samples were collected from the hospital environmental surfaces. The minimum inhibitory (MIC) and bactericidal concentrations (MBC) of disinfectants against S. aureus isolates were determined using the micro-broth dilution method. The qac genes (qacA, qacE, and qacΔE1) were detected by PCR and confirmed by sanger sequencing.
A total of 47 S. aureus strains were isolated, with more than 85% of them showing methicillin resistance. The qacA, qacE, and qac∆E1 genes were found in 23.4%, 29.7%, and 4.2% isolates respectively. All the isolates with qac genes had higher MIC and MBC values to selected disinfectants.
Significant methicillin resistant S. aureus (MRSA) contamination in the hospital environment was detected. Furthermore, higher qac gene frequencies were found in MRSA isolates that also correlated with higher MIC/MBC values to different disinfectants. The study proposes that hospitals should develop policies to determine disinfectant MICs against the common environmental isolates to contain the spread of resistant strains.
金黄色葡萄球菌是一种医院病原体，检测和阐明其对常规消毒剂的耐药机制可能有助于限制其在医疗机构环境表面的传播。在本研究中，研究了从医院环境中分离出的金黄色葡萄球菌菌株对消毒剂的敏感性，以及消毒剂耐药基因的存在与对消毒剂的敏感性降低之间可能存在的关联。
从医院环境表面采集了 245 个样本。使用微量肉汤稀释法测定消毒剂对金黄色葡萄球菌分离株的最小抑菌浓度（MIC）和杀菌浓度（MBC）。通过 PCR 检测 qac 基因（qacA、qacE 和 qacΔE1），并通过 Sanger 测序进行确认。
共分离出 47 株金黄色葡萄球菌，其中超过 85%的菌株表现出耐甲氧西林。qacA、qacE 和 qac∆E1 基因分别在 23.4%、29.7%和 4.2%的分离株中检出。所有携带 qac 基因的分离株对所选消毒剂的 MIC 和 MBC 值均较高。
检测到医院环境中存在大量耐甲氧西林金黄色葡萄球菌（MRSA）污染。此外，在与不同消毒剂的 MIC/MBC 值升高相关的 MRSA 分离株中发现了更高的 qac 基因频率。该研究提出医院应制定政策来确定针对常见环境分离株的消毒剂 MIC，以遏制耐药菌株的传播。
