Graduate School, Zhejiang Chinese Medical University, Hangzhou, China.
Zhuji People's Hospital of Zhejiang Province, Zhuji Affiliated Hospital of Shaoxing University, Zhuji, China.
Chemotherapy. 2022;67(1):37-46. doi: 10.1159/000520482. Epub 2021 Dec 6.
Emergence and prevalence of methicillin-resistant Staphylococcus aureus (MRSA) have become a major universal health concern, limiting therapeutic options.
A total number of 37 MRSA isolates, including 19 clinical isolates from hospitalized patients and 18 colonizing isolates from health care workers were identified from 3 hospitals, in Gorgan, North of Iran. Antimicrobial susceptibility test was performed using the disk diffusion method and E-test. The presence of virulence and antibiotic resistance determinants were evaluated by PCR. The genotypical characterization was further analyzed using multi-locus sequence, spa, staphylococcal cassette chromosome, mec (SCCmec), and agr typing.
The frequency of MRSA among S. aureus isolates was 38.14% (37/97). The most frequent S. aureus resistant isolates were found to be obstinate against penicillin (98%) and gentamicin (82.5%). Additionally, the lowest resistance rates were found against daptomycin (0%), vancomycin (2.7%), and quinupristin-dalfopristin (5.4%). All MRSA isolates were susceptible to daptomycin with minimum inhibitory concentration (MIC)50/MIC90 of 0.25/0.5 μg/mL. One isolate belonging to sequence type 239 (ST239)-SCCmecIII/t037 clone (MIC ≥16 μg/mL) was resistant to vancomycin. All but 1 isolate that shares ST22-SCCmec IV/t790 strain were positive for both tsst and pvl genes. The most predominant MRSA isolates (27%) were associated with ST239-SCCmec III/t037, and ST239-SCCmec III/t924 (16.2%) clones, subsequently. In our study, circulating MRSA strains were genetically diverse with a high prevalence of ST239-SCCmec III/t037 clone.
These findings emphasize the need for future and continuous surveillance studies on MRSA to prevent the dissemination of existing multidrug resistance MRSA clones in an effective manner.
耐甲氧西林金黄色葡萄球菌（MRSA）的出现和流行已成为全球主要的健康问题，限制了治疗选择。
从伊朗北部戈尔甘的 3 家医院中确定了 37 株 MRSA 分离株，包括 19 株来自住院患者的临床分离株和 18 株来自医护人员的定植分离株。采用纸片扩散法和 E 试验进行药敏试验。通过 PCR 评估毒力和抗生素耐药决定因素的存在。使用多位点序列、spa、葡萄球菌盒染色体、mec（SCCmec）和 agr 分型进一步分析基因型特征。
金黄色葡萄球菌分离株中 MRSA 的频率为 38.14%（37/97）。最常见的金黄色葡萄球菌耐药分离株对青霉素（98%）和庆大霉素（82.5%）耐药。此外，最低的耐药率出现在达托霉素（0%）、万古霉素（2.7%）和奎奴普丁/达福普汀（5.4%）。所有 MRSA 分离株对最低抑菌浓度（MIC）为 0.25/0.5μg/mL 的达托霉素均敏感。属于序列型 239（ST239）-SCCmecIII/t037 克隆（MIC≥16μg/mL）的 1 株分离株对万古霉素耐药。除 1 株携带 ST22-SCCmec IV/t790 株的分离株外，其余分离株均携带 tsst 和 pvl 基因。最主要的 MRSA 分离株（27%）与 ST239-SCCmec III/t037 和 ST239-SCCmec III/t924（16.2%）克隆相关。在我们的研究中，循环的 MRSA 菌株具有遗传多样性，ST239-SCCmec III/t037 克隆的流行率很高。
这些发现强调需要对 MRSA 进行未来和持续的监测研究，以有效防止现有多药耐药性 MRSA 克隆的传播。
