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MRSA Colonization and Infection in Swine Veterinarians

Project Description

Dates: 2011 – 2016

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.

SPECIFIC AIMS:

  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, and 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.

PROJECT UPDATES:

2015 Project Update

MRSA Colonization and Infection in Swine VeterinariansPublic health concern about the emergence of methicillin resistant Staphylococcal aureus (MRSA) in livestock, particularly pigs, is increasing. However, there is limited scientific information on the importance of livestock associated MRSA in human populations. The overall objective of this study is to analyze long-term patterns of S. aureus colonization (both methicillin resistant (MRSA) and methicillin susceptible (MSSA) strains) and infection of swine veterinarians. Concurrently, a survey of occupational hazards for US swine veterinarians and current practices for risk reduction is being conducted to assess 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 project will terminate in September 2014, and is in the final stages of analysis and reporting.

A study cohort of 68 swine veterinarians across 15 states was recruited to participate in a longitudinal study to determine the incidence and prevalence of nasal colonization of MRSA and MSSA. Compliance with sampling was outstanding (over 98%) yielding 1768 S. aureus isolates (including 207 MRSA). Monthly prevalence of S.aureus (58.3% to 82.4%) and MRSA (5.9% to 15.2%) exceeded US population estimates, and the predominant variants (MLST sequence type/spa type) detected were ST398/t034, ST5/t002 and ST9/t337 which similarly predominate among US pigs, suggesting that they are commonly contaminated with S. aureus from the swine population. The prevalence of MRSA was much lower than an estimate of 44% reported in a similar Dutch study, and remained relatively stable throughout the study. Most veterinarians are intermittently and transiently colonized, but a substantial minority (about 20%) appear to be persistently colonized. Furthermore, the data indicate that the nasal staphylococcal flora of swine veterinarians are predominantly of animal origin. A broader online survey of occupational health in swine veterinarians to determine the occurrence of occupationally related health events yielded 180 responses which are currently being analyzed to assess the personal protection practices of US swine veterinarians. This will include analysis of associations between risks of colonization/infection of swine veterinarians with MRSA/MSSA, exposure to pigs and the use of personal protective equipment.

This 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.

Project Personnel

PROJECT DIRECTOR

No results.

PROJECT PERSONNEL

CO-INVESTIGATORS

No results.

STAFF
Photo of My Yang

My Yang

Scientist Veterinary Population MedicineCollege of Veterinary Medicine, University of Minnesota
Phone: 612-626-5216
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Project Resources

Publications and Presentations

  • Hau S.J., Frana, T., Sun, J., Davies, P.R., & Nicholson, T.L. (2017). Zinc Resistance within Swine-Associated Methicillin-Resistant Staphylococcus aureus Isolates in the United States Is Associated with Multilocus Sequence Type Lineage, Applied and Environmental Microbiology. 83(15):e00756-17. https://doi.org/10.1128/AEM.00756-17
  • Hau, S.J., Sun, J., Davies, P.R., Frana, T.S., & Nicholson, T.L. (2015). Comparative prevalence of Immune Evasion Complex genes associated with β-Hemolysin converting bacteriophages in MRSA ST5 isolates from swine, swine facilities, humans with swine contact, and humans with no swine contact, PLoS One. 10(11):e0142832. https://doi.org/10.1371/journal.pone.0142832
  • Sun, J., Yang, M., Sreevatsan, S., & Davies, P.R. (2015). Prevalence and characterization of Staphylococcus aureus in growing pigs in the USA, PLoS One. 24;10(11):e0143670. https://doi.org/10.1371/journal.pone.0143670
  • Uhlemann A.C. et al. (2017). Evolutionary dynamics and international spread via routes of human migration of pandemic methicillin-sensitive S. aureus ST398, MBio. 8(1):e01375-16. https://doi.org/10.1128/MBIO.01375-16
  • Davies, P.R. (2012, Sept. 23-25). Livestock associated MRSA: What are the risks to human health? [Proceedings]. Allen D. Leman Swine Conference.
  • Davies, P.R. (2012, Oct. 27-31). Livestock associated MRSA – Tiger or pussycat? Proceedings, American Public Health Association. 140th Annual Meeting, San Francisco, CA, United States.
  • Davies, P.R. (2012, Nov. 7-13). Webinars for UMASH study participants.
  • Davies, P.R. (2012, Dec. 5-6). Emergence of livestock associated MRSA – occupational and public health consequences. North Carolina One Medicine Symposium – BUGS vs DRUGS: A One Medicine Approach to Antimicrobial Resistance, Durham, NC, United States.
  • Davies, P.R. (2013, March 2). Research update – Livestock associated MRSA. Human Health Committee, American Association of Swine Veterinarians, San Diego, CA, United States.
  • Davies, P.R. (2013, Apr. 17). Longitudinal study of Staphylococcus aureus and MRSA colonization of US swine veterinarians. UMASH Annual Forum, Saint Paul, MN, United States.
  • Davies, P.R. (2013, June 18-21). Patterns of S.aureus and MRSA colonization and infection in US swine veterinarians. 23rd Conference on Epidemiology in Occupational Health, Utrecht, Netherlands.
  • Davies, P. (2013, Sept. 9-12). Longitudinal study of Staphylococcus aureus in US swine veterinarians. SafePork 2013, Portland, ME, United States.
  • Davies, P. (2013, Sept. 16-17). Livestock associated MRSA: Tiger or pussycat? Leman Swine Conference, Minneapolis, MN, United States.
  • Davies, P. (2013, Nov. 4-7). MSSA spa types in US pigs and swine veterinarians correspond with MRSA spa types reported globally in swine. 3rd ASM-ESCMID Conference on Methicillin-resistant Staphylococci in Animals: Veterinary and Public Health Implications.
  • Davies, P. (2013, Nov. 4-7). The evaluation of molecular epidemiological relatedness within ST5 Staphylococcus aureus isolated from swine veterinarians in the USA. 3rd ASM-ESCMID Conference on Methicillin-resistant Staphylococci in Animals: Veterinary and Public Health Implications.
  • Davies, P., Sreevatsan, S., Sun, J., & Yang, M. (2014, Aug. 26-29). Longitudinal study of nasal carriage of Staphylococcus aureus in swine veterinarians and its implications for health. International Symposium on Staphylococci and Staphylococcal Infections, Chicago, IL, United States.
  • Davies, P.R., Sun, J., & Yang, M. (2014, Sept. 13-16). MRSA in the US swine industry – recent developments. Allen D. Leman Swine Conference, Saint Paul, MN, United States.
  • Sun, J. (2013, Sept. 9-12). Genetic diversity of ST5 Staphylococcus aureus isolated from swine veterinarians in the USA. SafePork 2013, Portland, ME, United States.
  • Sun, J. (2013, Sept. 16-17). The evaluation of molecular epidemiological relatedness within ST5 Staphylococcus aureus isolated from swine veterinarians in the USA. Leman Swine Conference, Minneapolis, MN, United States.
  • Sun, J. (2015, March 1-3). Quantitative evaluation of nasal carriage of Staphylococcus aureus in swine veterinarians. American Association of Swine Veterinarians, Orlando, FL, United States.
  • Sun, J. (2015, Nov. 2-5). Staphylococcus aureus and MRSA colonization and infection in US swine veterinarians: An 18 month longitudinal study. 4th ASM-ESCMID Conference on Methicillin-resistant Staphylococci in Animals: Veterinary and Public Health Implications, Chicago, IL, United States.
  • Sun, J., et. al. (2014, Dec. 7-8). Longitudinal study of nasal carriage of Staphylococcus aureus in swine veterinarians and its implications for health. Conference of Research Workers on Animal Disease, Chicago, IL, United States.
  • Sun, J., Sreevatsan, S., Knutson, T., Marthale, D., Yang, M., & Davies, P. (2017, May 5). Characterization of staphylococcus aureus in swine and swine veterinarians and its transmission at the human-livestock interface. NORA Symposium, Minneapolis, MN, United States.

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