Investigating Antibiotic-Resistant Staphylococcus aureus in Poultry: Dissertation Proposal

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

2. Introduction • Background • Significance • Goals • Specific Aims • Limitations of Current Literature & Research • Research Design & Methods • Strengths & Limitations

3. 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 http://www.medicinenet.com/mrsa_infection/page2.htm

4. 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

5. 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) http://www.takepart.com/news/tag/anti-factory-farming

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

7. Specific Aims • Establish the prevalence & molecular characteristics of AbRS. aureus on poultry farms • Establish the prevalence & molecular characteristics of AbRS. aureus in poultry processing facilities • Determine risk factors for presence of AbRS. aureus on farms or processing facilities

8. 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. http://www.sciencedaily.com/releases/2009/03/090316120846.htm

9. 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)

10. 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 http://newshopper.sulekha.com/turkey-farm_photo_1063248.htm

11. 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

12. 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

13. 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

14. Diagnostic Schematic

15. 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

16. 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

17. Strengths & Limitations 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

18. 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

19. 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

20. Project Timeline • Oct 2010 – Sept 2011: Farm Sampling • Dec 2010 – June 2012: Molecular analysis & antibiotic resistance testing • June – Sept 2012: Finish analysis & draft manuscript

21. Questions, Comments, or Concerns? http://ehsmanager.blogspot.com/2009/05/bacteria-create-aquatic-superbugs-in.html

22. Reference: www.Slideshare.com