DISSERTATION PROPOSAL: Abby L. H. Maples, MPH Antibiotic-resistant Staphylococcus aureus: Investigation of a poultry reservoir Department of Occupational & Environmental Health Sept.10, 2010

Introduction  Background  Significance  Goals  Specific Aims  Limitations of Current Literature & Research  Research Design & Methods  Strengths & Limitations

Background  Staphylococcus aureus  Signs & symptoms  Methicillin-resistant S. aureus (MRSA) Hospital 94,000 infections (Klevens, 2007) 18,000 deaths (Klevens, 2007) Community 1% of US population colonized (Graham, 2006; Kuehnert, 2006; Shorr, 2007) Livestock

Antibiotic-resistant S. aureus & Animals  S. aureus can cause infection in animals (Baptiste, 2005; De Neeling, 2007; Juhasz- Kaszanyitzky, 2007; Khanna, 2008; Smith, 2009; Van Loo, 2007; Weese, 2005; Weese, 2006)  Role of humans  Transient carriers or reservoirs?  Role of animals  Endemic?  Swine herds studied  Livestock-associated MRSA increasing

Antibiotic-resistant S. aureus in Environmental Samples  Airborne transmission  Colonization role?  Previous airborne transmission studies (Gibbs, 2004; Gibbs, 2006)  Surface contamination  Meat contamination (De Boer, 2009; Hanson, in press)

Goals  Long-term goal  Understand ecology & epidemiology of antibiotic- resistant (AbR)S. aureus  Objective  Characterize ecology & epidemiology of AbR S. aureus  Central hypothesis  Workers in close proximity to poultry are at risk of occupational exposure to AbR S. aureus  Farmers in contact with poultry will be colonized with MRSA

Specific Aims 1. Establish the prevalence & molecular characteristics of AbR S. aureus on poultry farms 2. Establish the prevalence & molecular characteristics of AbR S. aureus in poultry processing facilities 3. Determine risk factors for presence of AbR S. aureus on farms or processing facilities

Limitations of Current Literature  S. aureus is rapidly changing  Previous studies in chickens did not include workers  Epidemiologic studies in poultry have not been conducted in U.S.

Preliminary Studies  Prevalence of MRSA in Iowa & Illinois swine  18 swine farms in Iowa & Illinois (Smith, 2009)  9 each – confined animal feeding operations (CAFOs) & antibiotic-free systems  5/18 (27.7%) farms positive for MRSA  All CAFOs (55.5%, 5/9)  Prevalence in swine 43/428 (10.0%)  Prevalence in humans 29/89 (32.6%)  Humans working at CAFOs (45.3%, 29/64)

Research Design & Methods  Farm Description  Broilers, layers, and turkeys  Estimate 40% (± 5.0%) prevalence in poultry 95% confidence interval, 80% power = 600 animals 20 animals from 30 farms (10 each) Convenience Sample  Estimate 1-2 employees per farm Goal to enroll 60 humans

Research Design & Methods Continued  Sample Collection  IRB & IACUC Approved  Humans Nasal & throat Swabs Comparison, non-exposed group  Poultry Choanal (palatine) cleft & cloaca swabs  Air Sample Collection  6-stage Andersen Viable Cascade Impactor

Research Design & Methods Continued  Processing Facility Sample Collection  Estimate 25% prevalence in processing facilities  Surface & worker swabs of facility  Occupational Exposure Questionnaire  Animal exposure in last year  Demographic & behavioral questions  Farm Owner/Manager Questionnaire  Farm-specific questions

Research Design & Methods Continued  Bacterial Growth  6.5% Staph enrichment broth, CNA & CHROMagar  Microbiology  Gram stain, catalase, coagulase, S. aureus latex agglutination assay  MRSA confirmed by penicillin binding protein presence

Diagnostic Schematic

Research Design & Methods Continued  Molecular Typing  Spa typing  PVL PCR  Multilocus sequence typing (MLST)  Pulsed-Field Gel Electrophoresis (PFGE)  Antibiotic Resistance Testing  Broth dilution (CLSI standards)  Tested for susceptibility

Research Design & Methods Continued  Data and Statistical Analysis  Double-entry into databases Excel, Access, and Teleform Verifier  Unique specimen numbers  Multivariate modeling of risk factors (SAS) Logistic regression Cochran-Armitage trend test

Strengths & Limitations  First study of S. aureus in live poultry & workers in US  Well qualified & experienced team  Collaboration with ISU  Iowa is a national leader in eggs and turkey production  Convenience, single-time samples (not representative)  Pilot study  Limited geography  Limited farmer enrollment StrengthsLimitations

Impact & Benefit to Field  Assess infectious disease risks  Provide recommendations for preventative measures  Establish prevalence and dominant molecular types of S. aureus in poultry  Create potential implementations to prevent spread of S. aureus in rural Iowa

Three Publishable Paper Topics  Literature review of poultry diseases  Antibiotic resistant Staphylococcus aureus: Investigation into a poultry reservoir  Staphylococcus aureus in environmental samples and humans: Two poultry production facilities in Iowa(?)  Airborne Staphylococcus aureus in (10) poultry barns (?) **Open for discussion

Project Timeline  Oct 2010 – Sept 2011: Farm Sampling  Dec 2010 – June 2012: Molecular analysis & antibiotic resistance testing  June – Sept 2012: Finish analysis & draft manuscript Oct-Dec 2010 Jan-March 2011 April-June 2011 July-Sept 2011 Oct-Dec 2011 Jan-March 2012 April-June 2012 July-Sept 2012 Farm Sampling Molecular analysis & antibiotic resistance testing Finish analysis & draft manuscript

Questions, Comments, or Concerns?

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