Livestock Contact and MRSA in Rural Areas
Condition: Staphylococcus Aureus Infection
MeSH terms: Staphylococcal Infections
Study type: Observational

Summary: 
      Background:

      - MRSA is a type of bacteria that causes serious health problems. It can cause severe
      infections and is difficult to treat. MRSA has been found in a high number of people who work
      with some kinds of livestock, such as pigs. Researchers want to study people in rural areas,
      where more people work with or around livestock. They want to see if MRSA is more common or
      causes more serious infections in these areas.

      Objectives:

      - To look at the relationship between livestock handling (especially pigs) and MRSA bacteria
      in people in rural areas.

      Eligibility:

        -  Participants in the Agricultural Health Study in Iowa, including those who are exposed
           to livestock.

        -  Healthy volunteers who are not exposed to livestock.

      Design:

        -  This study requires an initial visit and monthly follow-up surveys for 18 months.

        -  At the first visit, participants will have throat and nose swabs to collect cell and
           bacteria samples. They will also complete a questionnaire about their health habits.
           Other questions will ask about any work that brings them into contact with livestock
           like cows, pigs, or chickens.

        -  Every month for the next 17 months, participants will complete another questionnaire to
           record any changes in their health and livestock contact information. They will also
           collect throat and nose swabs. They will send the questionnaires and the swabs to the
           study researchers.

        -  Participants will be paid for the first visit and for every monthly survey and swab
           collection they return.

        -  No treatment will be given as part of this protocol.
    

Detailed description: 
      The goal of this study is to understand the epidemiology of antibiotic-resistant S. aureus,
      including methicillin resistant S. aureus (MRSA), outside of the hospital environment. Our
      objective is to characterize the epidemiology of S. aureus in the rural community, focusing
      on persons who have contact with livestock. We will achieve this by carrying out two parallel
      prospective cohort studies in Iowa, examining 1) individuals enrolled in the Agricultural
      Health Study, including those who raise swine; and 2) a matched population-based group with
      no livestock exposure. We will partner with the state s microbiological diagnostic
      laboratories in order to collect isolates from the symptomatic S. aureus infections. Our
      central hypothesis is that individuals working in close proximity to livestock and poultry
      are at risk of occupational exposure to MRSA. We further hypothesize that farmers in contact
      with livestock (swine in particular) will be more likely to be colonized with
      swine-associated S. aureus strains than are individuals without contact. Finally, we expect
      to see both typical human strains of S. aureus (including USA300) as well as
      animal-associated strains (such as ST398) causing infections in Iowans. Our rationale is that
      successful completion will provide opportunities to institute an early warning system to
      evaluate emerging S. aureus strains, allowing for potential interventions prior to widespread
      dissemination in the human population. We will test our central hypothesis and accomplish the
      objective of this application by pursuing the following specific aims:

        1. Establish the prevalence, molecular subtypes, and antibiotic resistance profiles of S.
           aureus in populations of rural Iowans, and determine risk factors for colonization. We
           hypothesize that individuals in contact with swine will be more likely to carry MRSA
           than individuals lacking such exposure; that swine workers will more frequently be
           colonized with swine-associated strains such as ST398; and that S. aureus isolates
           collected from livestock farmers will more frequently demonstrate resistance to
           antibiotics including methicillin and tetracyclines than isolates collected from
           individuals lacking livestock exposure.

        2. Determine the incidence and molecular epidemiology of symptomatic S. aureus infections
           in rural Iowans. We hypothesize that symptomatic infections will be uncommon in our
           cohort relative to colonization, and that the majority of such infections will be skin
           and soft tissue infections. We further hypothesize that the majority of infections in
           our cohorts and elsewhere in the state will be caused by common strains (including
           USA300), but that some infections will also be caused by animal-associated strains,
           including ST398.
    

Observational model: Case-Control
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Individuals enrolled in the Agricultural Health Study, including those who raise swine; and
        a matched population-based group with no livestock exposure.
      
Keywords: Farming; Antibiotic Resistant; Bacteria