Department of Microbiology and Parasitology, Faculty of Medical Sciences, Naresuan University, Phitsanulok, Thailand.
Centre of Excellence in Medical Biotechnology, Faculty of Medical Sciences, Naresuan University, Phitsanulok, Thailand.
Int Microbiol. 2017 Jun;20(2):65-73. doi: 10.2436/20.1501.01.286.
The present study was conducted to isolate and characterize the molecular epidemiology of the methicillin-resistant staphylococci in the general university environment, where all five locations; the library, restrooms, canteens, computer rooms and outdoor surfaces, are in common use by a large population of students. We used Mannitol Salt Agar (MSA) supplemented with 4 μg/ml of oxacillin to screen the methicillin-resistant staphylococci. The species level was identified by PCR of rdr (Staphylococcus epidermidis), groESL (Staphylococcus haemolyticus) and nuc (Staphylococcus aureus and Staphylococcus warneri) genes and DNA sequencing of tuf and dnaJ genes. The susceptibility patterns of the isolates were determined using the disk diffusion method. Antibiotic and disinfectant resistance genes, together with SCCmec types, were detected by the PCR method. The methicillin resistant-staphylococci were isolated from 41 of 200 samples (20.5%), and all of them were found to be methicillin-resistant coagulase negative staphylococci (MR-CoNS). The library had the highest percentage of contamination, with 43.3% of the samples found to be contaminated. All isolates belonged to 6 different species including S. haemolyticus, S. epidermidis, S. warneri, S. cohnii, S. saprophyticus and S. hominis. The antimicrobial resistance rates were highest against penicillin (100%), then cefoxitin (73.1%), erythromycin (73.1%) and oxacillin (68.3%). Altogether, the isolates were approximately 61.0% multidrug resistant (MDR), with the S. epidermidis isolates being the most multidrug resistant. The prevalence of the qacA/B gene was detected in 63.4% of the isolates, and SCCmec could be typed in 43.9% (18/41) of the isolates. The type range was: II (n = 1), IVd (n = 1), I (n = 2), V (n = 6), IVa (n = 8) and untypeable (n = 23). This result indicates that these university environments are contaminated with methicillin-resistant coagulase negative staphylococci that carry various SCCmec types and high rate of disinfectant resistance genes. [Int Microbiol 20(2):65-73 (2017)].
本研究旨在分离和鉴定普通大学校园环境中耐甲氧西林葡萄球菌的分子流行病学特征，该环境中的所有五个地点（图书馆、洗手间、食堂、计算机房和室外表面）都被大量学生共同使用。我们使用添加了 4μg/ml 苯唑西林的甘露醇盐琼脂（MSA）来筛选耐甲氧西林葡萄球菌。通过 PCR 扩增 rdr（表皮葡萄球菌）、groESL（溶血性葡萄球菌）和 nuc（金黄色葡萄球菌和沃氏葡萄球菌）基因以及 tuf 和 dnaJ 基因的 DNA 测序来鉴定种属水平。采用纸片扩散法测定分离株的药敏模式。采用 PCR 法检测抗生素和消毒剂耐药基因以及 SCCmec 型。从 200 个样本中的 41 个样本（20.5%）中分离出耐甲氧西林葡萄球菌，均为耐甲氧西林凝固酶阴性葡萄球菌（MR-CoNS）。图书馆的污染率最高，43.3%的样本被污染。所有分离株属于 6 个不同的种，包括溶血性葡萄球菌、表皮葡萄球菌、沃氏葡萄球菌、科氏葡萄球菌、腐生葡萄球菌和人葡萄球菌。青霉素（100%）、头孢西丁（73.1%）、红霉素（73.1%）和苯唑西林（68.3%）的耐药率最高。总的来说，分离株的多药耐药率约为 61.0%，其中表皮葡萄球菌分离株的多药耐药性最高。在 63.4%的分离株中检测到 qacA/B 基因，在 41 个分离株中的 43.9%（18/41）可对 SCCmec 进行分型。类型范围为：II 型（n=1）、IVd 型（n=1）、I 型（n=2）、V 型（n=6）、IVa 型（n=8）和不可分型（n=23）。这表明这些大学校园环境受到携带各种 SCCmec 型和高消毒剂耐药基因的耐甲氧西林凝固酶阴性葡萄球菌的污染。[国际微生物学 20（2）：65-73（2017）]。
