Erzincan Binali Yildirim University, Faculty of Medicine, Department of Medical Microbiology, Erzincan, Turkey.
Erzincan Binali Yildirim University, Faculty of Medicine, Department of Medical Microbiology, Erzincan, Turkey; KTO Karatay University, Faculty of Medicine, Department of Medical Microbiology, Konya, Turkey.
J Infect Public Health. 2019 Jul-Aug;12(4):528-533. doi: 10.1016/j.jiph.2019.01.063. Epub 2019 Feb 7.
mecA is a predefined gene causing methicillin resistance in Staphylococcus aureus (S. aureus) isolates; however, it has been shown that some methicillin-resistant S. aureus (MRSA) strains do not carry this gene. Recently, in isolates found to be MRSA-positive but mecA-negative, a new resistance gene called mecC, which is a homolog of mecA, has been reported. This study aimed to investigate the mecC and mecA genes in MRSA strains isolated from different geographic regions in Turkey.
The sample of the study consisted of 494 MRSA strains isolated from seven geographical regions in Turkey between 2013 and 2016. The strains were obtained from 17 centers, comprising 13 university hospitals, three education and research hospitals, and one state hospital. Methicillin resistance in S. aureus strains was determined using the agar disk diffusion method with a cefoxitin disk and the agar dilution method with oxacillin. The mecC and mecA genes in MRSA strains was investigated by Polymerase Chain Reaction (PCR).
Of the MRSA strains investigated, 47.9% were isolated from intensive care units. Concerning sample type, 36.7% were detected in the respiratory tract (tracheal aspirate, sputum, etc.), 24.8% in blood, 18.7% in skin and soft tissues, 9.3% in nasal swabs, 5.4% in urine, 4.1% in ears, and 1% in sterile body fluid. Using PCR, mecC was not identified in any of the S. aureus strains isolated from different clinical microbiology laboratories. mecA gene positivity was found in 315 of the MRSA strains (63.8%). Staphylococcal Cassette Chromosome mec (SCCmec) type was identified in 232 strains (46.9%), of which 136 (58.7%) were type II, 75 (32.4%) were type IV, 12 (5.1%) were type IIIb, six (2.5%) were type I, and three (1.3%) were type III.
This is the first multi-centered study to investigate MRSA strains isolated from different regions in Turkey. The mecC gene was not detected in any of the MRSA strains. We believe that this study will constitute an important basis for monitoring possible future changes.
mecA 是一个预先定义的基因，导致金黄色葡萄球菌（S. aureus）分离株对甲氧西林耐药；然而，已经表明一些耐甲氧西林金黄色葡萄球菌（MRSA）株不携带该基因。最近，在被发现为 MRSA 阳性但 mecA 阴性的分离株中，已经报道了一种新的耐药基因，称为 mecC，它是 mecA 的同源物。本研究旨在调查来自土耳其不同地理区域的 MRSA 菌株中 mecC 和 mecA 基因。
本研究的样本包括 2013 年至 2016 年期间从土耳其七个地理区域分离的 494 株 MRSA 菌株。这些菌株来自 17 个中心，包括 13 家大学医院、3 家教育和研究医院以及 1 家州立医院。使用头孢西丁纸片扩散法和 oxacillin 琼脂稀释法测定金黄色葡萄球菌菌株的甲氧西林耐药性。通过聚合酶链反应（PCR）研究 MRSA 菌株中的 mecC 和 mecA 基因。
在所研究的 MRSA 菌株中，47.9%分离自重症监护病房。关于样本类型，36.7%在呼吸道（气管抽吸物、痰等）中检出，24.8%在血液中，18.7%在皮肤和软组织中，9.3%在鼻拭子中，5.4%在尿液中，4.1%在耳朵中，1%在无菌体液中。使用 PCR，在从不同临床微生物学实验室分离的金黄色葡萄球菌株中均未鉴定出 mecC 基因。在 315 株 MRSA 株（63.8%）中发现 mecA 基因阳性。在 232 株菌（46.9%）中鉴定出葡萄球菌盒染色体 mec（SCCmec）型，其中 136 株（58.7%）为 II 型，75 株（32.4%）为 IV 型，12 株（5.1%）为 IIIb 型，6 株（2.5%）为 I 型，3 株（1.3%）为 III 型。
这是首次在土耳其不同地区进行的多中心研究，调查从不同地区分离的 MRSA 菌株。在任何一株 MRSA 菌株中均未检测到 mecC 基因。我们相信，这项研究将为监测未来可能发生的变化提供重要依据。
