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ORIGINAL RESEARCH article

Front. Microbiol.
Sec. Infectious Agents and Disease
Volume 16 - 2025 | doi: 10.3389/fmicb.2025.1512461

Dissemination of Staphylococcus epidermidis in Swedish bovine dairy herds: Minimal overlap with human isolates

Provisionally accepted
Karin Persson Waller Karin Persson Waller 1Mattias Myrenäs Mattias Myrenäs 1Hyeyoung Kim Hyeyoung Kim 2Micael Widerström Micael Widerström 3*Tor Monsen Tor Monsen 3Stefan Börjesson Stefan Börjesson 4Emma Östlund Emma Östlund 5Wonhee Cha Wonhee Cha 2
  • 1 Department of Animal Health and Antimicrobial Strategies, Swedish Veterinary Agency (SVA), Uppsala, Sweden
  • 2 Department of Epidemiology, Surveillance and Risk assessment Disease Control and Epidemiology, Swedish Veterinary Agency (SVA), Uppsala, Sweden
  • 3 Clinical Microbiology, Umeå University, Umea, Sweden
  • 4 Department of Food Safety and Animal Health Research, Norwegian Veterinary Institute, N-1431 Ås, Norway
  • 5 Department of Microbiology, Swedish Veterinary Agency (SVA), Uppsala, Sweden

The final, formatted version of the article will be published soon.

    Knowledge of zoonotic links between bovine and human isolates of Staphylococcus epidermidis remains limited. The primary aim of this study was to assess the genetic relatedness of S. epidermidis isolates from bovine subclinical mastitis (SCM), bovine milk filters, healthy dairy farmers or farm personnel, and human hospital patients in Sweden, and to detect and compare genes encoding antimicrobial resistance (AMR) and virulence factors. A secondary aim was to explore the epidemiology of bovine S. epidermidis intramammary infections (IMI) by examining associations between genotypes and geographic location, persistence of IMI, severity of inflammatory response, and the persistence of S. epidermidis strains over time. A total of 283 S. epidermidis isolates were analyzed using whole genome sequencing (WGS): 128 SCM milk isolates, 55 milk filter isolates, 13 farmer/personnel isolates and 87 human patient isolates. Sixty unique sequence types (STs) of S. epidermidis were identified. ST99, ST100 and ST570 were the most common among bovine isolates, collectively accounting for 49% (63/128) of the milk isolates and detected on multiple farms, while ST2 and ST215 were the most prevalent among human isolates. Only four STs (ST59, ST73, ST Begränsad delning and ST218), representing a total of 13 isolates, were found in both bovine and human samples. Genes conferring AMR were more frequently identified in human patient isolates compared to bovine isolates. However, penicillin resistance, identified by presence of the blaZ gene, was detected in 42% of bovine S. epidermidis isolates. The average number of potential virulence factors (pVF) per isolate was 23.8 with 23.1 in milk isolates, 23.4 in milk filter isolates, 23.0 in farmer/personnel isolates, and 25.2 in human patient isolates. There was some variation in the total number of pVFs and the presence of specific pVFs or functional groups of pVFs between sample types and STs. In conclusion, the results indicate that the overlap of STs and AMR genes between humans and bovine samples was minimal. However, the persistence of certain STs across multiple dairy farms suggests inter-farm transmission. This study provides new insights into the epidemiology of bovine S. epidermidis IMI, with implications for the control of these infections.

    Keywords: Mastitis, dairy cows, WGS -whole-genome sequencing, Antimicrobial resistance (AMR) genes, virulence factors (VF), Staphylococcus epidermidis, One Health (OH) -Approach

    Received: 16 Oct 2024; Accepted: 13 Jan 2025.

    Copyright: © 2025 Persson Waller, Myrenäs, Kim, Widerström, Monsen, Börjesson, Östlund and Cha. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Micael Widerström, Clinical Microbiology, Umeå University, Umea, Sweden

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