Gergova Raina, Tsitou Virna-Maria, Dimov Svetoslav G, Boyanova Lyudmila, Mihova Kalina, Strateva Tanya, Gergova Ivanka, Markovska Rumyana
1Department of Medical Microbiology, Faculty of Medicine, Medical University of Sofia, Sofia, Bulgaria.
2Department of Genetics, Sofia University "St. Kliment Ohridski", Sofia, Bulgaria.
Acta Microbiol Immunol Hung. 2022 Jun 21;69(3):193-200. doi: 10.1556/030.2022.01766. Print 2022 Sep 16.
Severe infections of virulent methicillin-resistant Staphylococcus aureus (MRSA) are a serious health problem. The present study aimed to investigate clonal spread, virulence and antimicrobial resistance rates of Bulgarian MRSA isolates in 2016-2020.
Molecular identification and mecA gene detection were performed with PCR. Clonal relatedness was evaluated by RAPD PCR and MLST. MRSA epidemiology, virulence and resistance patterns were investigated by PCR.
All 27 isolates were identified as S. aureus and were mecA positive, and all were susceptible to linezolid, tigecycline and vancomycin. The toxin genes hlg (in 92.6% of isolates), seb (77.8%), sei (77.8%), seh (59.3%), sej (55.6%), and seg (48.1%), were frequently found among the isolates. Epidemiological typing by RAPD identified 4 clones (16 isolates) and 11 were with a unique profile. MLST analysis of the same MRSA isolates showed five MLST clonal complexes and 11 ST types, including CC5 (33.3%) (ST5, ST221, ST4776), CC8 (22.2%) (ST8, ST239, ST72), CC15 (ST582), CC22 (14.8%) (ST217, ST5417), CC30 (ST30) CC398 (ST398), and CC59 (ST59). The isolates from CC5 showed higher virulence potential and almost all were macrolide resistant (ermB or ermC positive). CC8 isolates showed higher level of resistance.
To the best of our knowledge, this study is the first describing the clonal spreading of Bulgarian MRSA and the association with their virulence and resistance determinants. Monitoring of MRSA epidemiology, resistance and virulence profile can lead to better prevention and faster therapeutic choice in cases of severe infections.
强毒力耐甲氧西林金黄色葡萄球菌（MRSA）的严重感染是一个严重的健康问题。本研究旨在调查2016 - 2020年保加利亚MRSA分离株的克隆传播、毒力和抗菌药物耐药率。
采用PCR进行分子鉴定和mecA基因检测。通过RAPD PCR和MLST评估克隆相关性。通过PCR研究MRSA的流行病学、毒力和耐药模式。
所有27株分离株均被鉴定为金黄色葡萄球菌且mecA呈阳性，所有分离株对利奈唑胺、替加环素和万古霉素均敏感。毒素基因hlg（92.6%的分离株）、seb（77.8%）、sei（77.8%）、seh（59.3%）、sej（55.6%）和seg（48.1%）在分离株中频繁出现。通过RAPD进行的流行病学分型鉴定出4个克隆（16株分离株），11株具有独特的图谱。对相同MRSA分离株的MLST分析显示有5个MLST克隆复合体和11个ST型，包括CC5（33.3%）（ST5、ST221、ST4776）、CC8（22.2%）（ST8、ST239、ST72）、CC15（ST582）、CC22（14.8%）（ST217、ST5417）、CC30（ST30）、CC398（ST398）和CC59（ST59）。来自CC5的分离株显示出更高的毒力潜力，几乎所有分离株对大环内酯类耐药（ermB或ermC呈阳性）。CC8分离株显示出更高水平的耐药性。
据我们所知，本研究首次描述了保加利亚MRSA的克隆传播及其与毒力和耐药决定因素的关联。监测MRSA的流行病学、耐药性和毒力谱可在严重感染病例中实现更好的预防和更快的治疗选择。
