University of Minnesota
University of Minnesota


MRSA Colonization and Infection in Swine Veterinarians

Principal Investigator: Peter Davies, BVSc, Ph.D.
Co-Investigators: Claudia Munoz-Zanzi, DVM, MPVM, Ph.D., Srinand Sreevatsan, DVM, Ph.D.

Methicillin-resistant Staphylococcus aureus (MRSA) was long perceived as a problem confined to the human medical arena, with animal reservoirs being of negligible epidemiological significance. Livestock associated MRSA (LA-MRSA) is a recently recognized and emerging pathogen, and the epidemiology and public health implications of these organisms are poorly understood. This group of organisms appears to occur widely in swine populations worldwide, including in the USA. Fundamental information about the incidence and duration of colonization of people with LA-MRSA , and the associated risks of clinical infection, is lacking as there has been no long term longitudinal study of occupationally exposed individuals. This issue is currently one of great concern among the swine veterinary community due to the high media profile and potential risks to the veterinarians themselves and to their clients.

The overall objective of this study is to analyze long term patterns of S. aureus colonization and infection of swine veterinarians. The study will include both methicillin resistant (MRSA) and methicillin susceptible (MSSA) strains of S. aureus, which will be typed to determine whether they are livestock associated strains. Concurrently, a survey of occupational hazards for US swine veterinarians and current practices for risk reduction will be conducted to assess of current practices in relation to existing recommendations and guide educational efforts to promote better practices for veterinarians and other groups who are occupationally exposed to animals.

The specific aims of the study are as follows.

  1. Determine the incidence and prevalence of nasal colonization of swine veterinarians with S. aureus (including MRSA and MSSA) in the USA
    It is well established from cross-sectional studies that people with occupational exposure to livestock (particularly pigs and cattle) have a high prevalence of nasal colonization with MRSA. There is little information on the duration or stability of colonization, or its association with clinical staphylococcal infections. We will conduct a prospective study of a cohort of swine veterinarians to describe temporal patterns colonization with livestock associated MRSA and MSSA in a cohort of veterinarians over 18 months.

  2. Determine the incidence of occupationally related health events in US swine veterinarians, focusing on skin and soft tissue infections.
    Despite the high prevalence of exposure, there are no published prospective studies evaluating the clinical implications of exposure to livestock associated S. aureus. This is a critical gap in understanding of the public health implications of livestock associated MRSA. As part of a broader study of occupationally related health events in our study cohort, we will focus on the incidence of skin and soft tissue infections

  3. Describe use of personal protection  practices of  US swine veterinarians
    Current practices of swine veterinarians to prevent exposure to zoonotic agents are not well documented. We will assess attitudes and practices of veterinarians about perceived occupational risks of infectious diseases (including MRSA) in a broad cross-sectional survey as well as in the study cohort. The findings may be used to guide development of educational materials for veterinary graduates and students, as well as other livestock workers.

  4. Quantify associations between risks of colonization/ infection of swine veterinarians with MRSA/MSSA and exposure to pigs and use of PPE.
    Associations of exposure to pigs and personal protection practices of veterinarians with nasal colonization with MRSA and MSSA will be explored using data from Objectives 1, 2 and 3 to identify potential risk factors for interspecies transmission.

Collectively, the project will provide the first longitudinal assessment of the risk of human colonization and infection with livestock associated MRSA and its association with animal contact and personal protection practices. This information will be relevant to continuing education of veterinarians and farmers with respect to reducing occupational risk of zoonotic disease.

Project Personnel

Peter Davies

Peter Davies, BVSc, Ph.D.
Professor, Swine Health and Production
Veterinary Population Medicine
College of Veterinary Medicine, University of Minnesota
Phone: 612-625-8290

Principal Investigator

Claudia Muniz-Zanzi

Claudia Munoz-Zanzi, DVM, MPVM, Ph.D.
Associate Professor
Epidemiology and Community Health
School of Public Health, University of Minnesota
Phone: 612-626-2849


Srinand Sreevatsan

Srinand Sreevatsan, DVM, Ph.D.
Associate Professor, Veterinary Population Medicine
College of Veterinary Medicine, University of Minnesota
Phone: 612-625-3769


Photo Not Available

Leticia Linhares, DVM
Research Assistant
College of Veterinary Medicine, University of Minnesota
Phone: 612-284-4588

Research Assistant

Jisun Sun DVM

Jisun Sun, DVM
Research Assistant
College of Veterinary Medicine, University of Minnesota

Research Assistant

Stephen Waring

My Yang
Scientist, Veterinary Population Medicine
College of Veterinary Medicine, University of Minnesota
Phone: 612-626-5216





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