Department of Animal and Environmental Hygiene, University of Life Sciences in Lublin, Akademicka 13, 20-950 Lublin, Poland.
Department of Medical Microbiology, Institute of Microbiology, Faculty of Biology, University of Warsaw, I. Miecznikowa 1, 02-096 Warsaw, Poland.
J Dairy Sci. 2020 Nov;103(11):10577-10584. doi: 10.3168/jds.2020-18291. Epub 2020 Sep 28.
Staphylococcus aureus is a widely recognized pathogen responsible for many serious diseases in both humans and animals. It is also one of the major causative agents of bovine mastitis. Methicillin-resistant S. aureus (MRSA), although relatively rare in this pathology, has been increasingly reported in livestock animals, mainly in pigs, but also cattle, sheep, and poultry. The recent emergence of livestock-associated (LA-)MRSA is cause for an immediate public health concern due to the risk of zoonotic transmission to humans, and is of particular concern for people who work in animal husbandry or have prolonged contact with livestock animals. This study reports on the first LA-MRSA outbreak in dairy cattle and the first probable case of MRSA transmission between humans and cows in Poland. A single dairy farm located in Eastern Poland was monitored on a regular basis for the occurrence of mastitis. Over a 1-yr study period, 717 quarter-milk samples from 583 cows were collected and examined microbiologically. A total of 5 MRSA isolates from as many cows with subclinical mastitis were cultured. They all belonged to the same outbreak, given a 2-mo time window in which they were identified. During the outbreak, 24 oral and nasal swabs were voluntarily taken from 6 people: a milker, a veterinarian, and 4 members of the veterinarian's family. Eight swabs from a milker, veterinarian, and 2 family members yielded positive MRSA cultures. All MRSA isolates were genotyped with a combination of multiple-locus variable number tandem repeat analysis, multilocus sequence typing, and staphylococcal protein A gene (spa) typing. Eleven bovine (n = 5; 5 cases) and human (n = 6; 4 cases) isolates showed an identical drug-susceptibility profile and were indistinguishable upon multiple-locus variable number tandem repeat analysis (pattern A), multilocus sequence typing (ST398) and spa (t034) typing. The results of this study provide the evidence of transmission of MRSA between humans and cows, and between humans in the family setting. This work, despite being a preliminary investigation, underscores the risk of intra- and interspecies transmission of LA-MRSA and urges enhancement of the existing biosecurity measures aimed at preventing MRSA (and other milk pathogens) spread at both the farm- and household levels.
金黄色葡萄球菌是一种广泛公认的病原体，可导致人类和动物的许多严重疾病。它也是牛乳腺炎的主要病原体之一。耐甲氧西林金黄色葡萄球菌（MRSA）虽然在这种病理学中相对较少，但在牲畜动物中，主要是在猪中，但也在牛、羊和家禽中，越来越多地被报道。由于其对人类的人畜共患病传播风险，最近出现的与牲畜相关的（LA-）MRSA 引起了人们对公共卫生的立即关注，并且对从事畜牧业的人和与牲畜有长期接触的人特别关注。本研究报告了波兰首例奶牛中 LA-MRSA 暴发和首例人类与奶牛之间 MRSA 传播的可能病例。在波兰东部的一个单一奶牛场定期监测乳腺炎的发生情况。在为期 1 年的研究期间，从 583 头奶牛中采集了 717 份季度奶样进行微生物学检查。从 5 头患有亚临床乳腺炎的奶牛中培养出 5 株 MRSA 分离株。由于它们是在 2 个月的时间窗口内鉴定的，因此都属于同一暴发。在暴发期间，从 6 个人中自愿采集了 24 个口腔和鼻腔拭子：挤奶工、兽医和兽医的 4 名家庭成员。挤奶工、兽医和 2 名家庭成员的 8 个拭子培养出 MRSA 阳性。所有 MRSA 分离株均通过多位点可变数量串联重复分析、多位点序列分型和葡萄球菌蛋白 A 基因（spa）分型进行基因分型。11 株牛（n = 5；5 例）和人（n = 6；4 例）分离株显示出相同的药物敏感性谱，并且在多位点可变数量串联重复分析（模式 A）、多位点序列分型（ST398）和 spa（t034）分型中无法区分。这项研究的结果提供了 MRSA 在人类和奶牛之间以及家庭环境中人与人之间传播的证据。尽管这是一项初步调查，但强调了 LA-MRSA 在种内和种间传播的风险，并敦促加强旨在防止 MRSA（和其他牛奶病原体）在农场和家庭层面传播的现有生物安全措施。
