Avberšek Jana, Golob Majda, Papić Bojan, Dermota Urška, Grmek Košnik Irena, Kušar Darja, Ocepek Matjaž, Zdovc Irena
Veterinary Faculty, Institute of Microbiology and Parasitology, University of Ljubljana, Ljubljana, Slovenia.
National Laboratory of Health, Environment and Food, Kranj, Slovenia.
Transbound Emerg Dis. 2021 Mar;68(2):789-801. doi: 10.1111/tbed.13745. Epub 2020 Aug 31.
Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) represents a concern in both human and veterinary medicine. The aim of this study was to investigate potential LA-MRSA transmission between animals and humans in rural settings. To this aim, a study was designed to include 14 farms in Slovenia, which were selected on the basis of a farmer (initial patient) with confirmed LA-MRSA infection and regular animal contacts. On all farms, the initial patients, their household members, animals and barn environment were analysed for the presence of LA-MRSA. In addition, the epidemiologically linked hospital-related LA-MRSA isolates were included to investigate possible nosocomial transmissions. On five farms, LA-MRSA was discovered both in animals and in humans. In total, 49 LA-MRSA isolates of different origins underwent whole-genome sequencing, antimicrobial susceptibility testing and spa typing. All 49 isolates belonged to the sequence type 398 (ST398), spa types t011 and t034, and harboured staphylococcal chromosomal cassette mec Vc. High levels of concordance between resistance phenotypes and genotypes were observed. No transmission pairs between animals and initial patients were discovered. However, several isolates originating from farm animals and other household members formed clusters with pairwise distances of ≤14 single nucleotide polymorphisms (SNPs), indicating recent transmission events. In addition, three closely related isolates (0 SNP) form hospitalized patients were observed, indicating a possible nosocomial transmission. Two hospital-related isolates harboured the immune evasion cluster genes, which are associated with adaptation to the human host; however, these two isolates differed in >30 SNPs from the remaining isolates. Characteristics of LA-MRSA from Slovenia reflect those observed previously in other European studies. Immune evasion cluster-positive LA-MRSA ST398 suggests its re-adaptation to the human host and calls for a closer monitoring of such emerging LA-MRSA lineages, in addition to monitoring and preventing the introduction of LA-MRSA from farms to hospitals where transmission is highly plausible.
家畜相关的耐甲氧西林金黄色葡萄球菌（LA-MRSA）在人类医学和兽医学领域都备受关注。本研究旨在调查农村地区动物与人类之间潜在的LA-MRSA传播情况。为此，设计了一项研究，纳入了斯洛文尼亚的14个农场，这些农场是根据有确诊LA-MRSA感染且经常接触动物的农民（初始患者）来选择的。在所有农场中，对初始患者、其家庭成员、动物和畜舍环境进行了LA-MRSA检测。此外，纳入了与医院相关的、在流行病学上有联系的LA-MRSA分离株，以调查可能的医院内传播情况。在5个农场中，动物和人类体内均发现了LA-MRSA。总共对49株不同来源的LA-MRSA分离株进行了全基因组测序、抗菌药物敏感性测试和spa分型。所有49株分离株均属于序列型398（ST398），spa型为t011和t034，并携带葡萄球菌染色体盒式mec Vc。观察到耐药表型和基因型之间具有高度一致性。未发现动物与初始患者之间的传播配对。然而，一些来自动物和其他家庭成员的分离株形成了聚类，其单核苷酸多态性（SNP）的成对距离≤14，表明近期发生了传播事件。此外，观察到3株来自住院患者的密切相关分离株（0个SNP），表明可能存在医院内传播。2株与医院相关的分离株携带免疫逃避簇基因，这些基因与适应人类宿主有关；然而，这2株分离株与其余分离株的SNP差异超过30个。斯洛文尼亚LA-MRSA的特征与之前其他欧洲研究中观察到的特征相符。免疫逃避簇阳性的LA-MRSA ST398表明其重新适应了人类宿主，并呼吁除了监测和防止LA-MRSA从农场传入传播可能性很高的医院外，还需更密切地监测此类新兴的LA-MRSA谱系。
