The Impact of Hog Production and Staphylococcus aureus Nasal Carriage on the Microbiome of Pigs, Pigs Workers and Community Residents, North Carolina, USA

Details

• Personal Author:
  Brown AT
• Description:
  Background: Industrial hog operation (IHO) densities have increased over the years in the United States with predominance in rural communities in Iowa and North Carolina. IHOs may serve as a reservoir for diverse microorganisms and create unique opportunities for microbial selection and adaptation in animal and human hosts. A critical concern lies in the sub-therapeutic, rather than therapeutic, use of antibiotics to enhance the growth of livestock, which can contribute substantially to selection of antimicrobial resistance (AMR) for medically important antibiotics. Emerging livestock-associated (LA-) strains of S. aureus (including methicillin-resistant S. aureus [MRSA]) have been isolated from livestock, including pigs, and are prevalent on IHOs, among IHO workers, their household contacts, and in communities with high densities of IHOs. It is unclear the degree to which AMR S. aureus strains in general-and AMR LA- S. aureus from IHOs in particular-impact other members of the bacterial community (microbiome) and whether occupational exposure to IHOs can influence and contribute LA-microbiota to human hosts. Hypothesis: The overarching hypothesis of this dissertation is that pigs will demonstrate microbiome composition and diversity profiles that differ by mode of production and use of antimicrobials (IHO vs. antibiotic-free hog operations [AFHO]) and that there will be a transfer of the IHO pig microbiota to IHO workers and their household and community contacts. I further hypothesize that nasal microbiome composition and diversity profiles will differ by intensity of IHO work activities, S. aureus nasal carriage outcomes, and LA-microbial exposure markers. Methods: Nasal swab samples from: 1) IHO pigs, IHO workers and children living in their households; 2) AFHO pigs and AFHO workers; and 3) community resident (CR) adults with no known livestock exposure and children living in their households were sequenced targeting the V4 region of the 16S rRNA gene. QIIME, a bioinformatics tool, was used to generate microbiome measures. We assessed differences in: 1) alpha diversity (Shannon diversity, observed OTUs, phylogenetic distance 2) beta diversity (weighted UniFrac, unweighted UniFrac, Bray Curtis, Binary Jaccard and Morisita-Horn); 3) and relative abundance and presence/absence of genera by participant type and S. aureus nasal carriage outcomes (S. aureus, multidrug-resistant S. aureus [MDRSA], and scn-negative S. aureus [a marker of livestock association]). Beta diversity differences were visualized spatially using non-metric dimensional scaling (NMDS). We used linear regression models and non-parametric Adonis methods to estimate associations of personal, household, and occupational characteristics and S. aureus nasal carriage outcomes with changes in alpha diversity, beta diversity, and IHO pig bacterial contributions. Additionally, bacterial taxa that were significantly different between participant types were identified and log2 transformed to display differences in relative abundance of taxa present in IHO pigs versus AFHO pigs and IHO workers versus AFHO workers. Lastly, bacterial taxa contributed from the pig were identified for each of the human participant groups' nasal microbiomes. Results: The first aim showed that the microbiomes of IHO pigs and IHO workers demonstrated lower alpha diversity and a greater relative abundance of pathogenic bacterial taxa than AFHO pigs and AFHO workers. IHO pigs contributed a greater number of bacterial taxa to IHO workers than AFHO pigs contributed to AFHO workers. Aim two demonstrated that IHO work activities and exposures and S. aureus nasal carriage outcome measures (S. aureus, MDRSA, and scn-negative S. aureus) correlated with bacterial community differences among IHO workers. IHO pig bacterial contributions correlated with beta diversity differences of IHO children and CR adults and CR children with no known livestock exposure. Finally, in aim three, we observed consistent positive associations between presence versus absence LA-microbial markers nasal carriage ( scn-negative S. aureus, Pig-2-Bac, and IHO pig bacterial contributions) and beta diversity over time among IHO workers but not among children living in their households. Conclusions: Overall the results of this thesis support our hypotheses that microbiome composition and diversity profiles are impacted by mode of hog production and use of antimicrobial drugs. This may occur directly through the transfer of OTUs from the pig microbiota to hog workers via work activities and exposures or indirectly to members of IHO workers households and community residents with no known livestock exposure. This thesis suggests that the nasal microbiome may represent a useful exposure assessment tool to characterize the influence of hog production practices (e.g. antimicrobial use and confinement) on the microbiome of pigs, pig workers and their household contacts, and community residents living proximal to high-density hog production. [Description provided by NIOSH]
• Subjects:
  Animals Livestock Microbiology Nose Occupational Exposure Occupational Health Safety Sense Organs
• Keywords:
  Animal Handlers Animal Husbandry Workers Antimicrobial Resistance Infectious Agents Livestock Industry Nasal Cavity Occupational Exposure Staphylococcus Aureus
• ISBN:
  9781392068335
• Publisher:
  ProQuest LLC.
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Dissertation
• Place as Subject:
  Maryland ; North Carolina ; OSHA Region 3 ; OSHA Region 4
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• NIOSHTIC Number:
  nn:20059218
• Citation:
  Ann Arbor, MI: ProQuest LLC., 2018 Aug; :13890123
• Federal Fiscal Year:
  2018
• Performing Organization:
  Johns Hopkins University
• Peer Reviewed:
  False
• Start Date:
  20050701
• Source Full Name:
  The impact of hog production and Staphylococcus aureus nasal carriage on the microbiome of pigs, pigs workers and community residents, North Carolina, USA
• End Date:
  20280630
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:a632dd8857efee0b0a54363b8f90f75685f6c97e5a27ca5608fb5b517c9e3db615bd30a5f6605222a9e50bf14891ca807259f507b4590357134aae233edebfec
• Download URL:
  https://stacks.cdc.gov/view/cdc/223507/cdc_223507_DS1.pdf
• File Type:
  [PDF - 11.77 MB ]