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The role of the environment in the emergence and spread of antimicrobial resistance (AMR) is being increasingly recognized, raising questions about the public health risks associated with environmental AMR. Yet, little is known about pathogenicity among resistant bacteria in environmental systems. Existing studies on the association between AMR and virulence are contradictory, as fitness costs and genetic co-occurrence can be opposing influences. Using Escherichia coli isolated from surface waters in eastern North Carolina, we compared virulence gene prevalence between isolates resistant and susceptible to antibiotics. We also compared the prevalence of isolates from sub-watersheds with or without commercial hog operations (CHOs). Isolates that had previously been evaluated for phenotypic AMR were paired by matching isolates resistant to any tested antibiotic with fully susceptible isolates from the same sample date and site, forming 87 pairs. These 174 isolates were evaluated by conventional PCR for seven virulence genes (bfp, fimH, cnf-1, STa (estA), EAST-1 (astA), eae, and hlyA). One gene, fimH, was found in 93.1% of isolates. Excluding fimH, at least one virulence gene was detected in 24.7% of isolates. Significant negative associations were found between resistance to at least one antibiotic and presence of at least one virulence gene, tetracycline resistance and presence of a virulence gene, resistance and STa presence, and tetracycline resistance and STa presence. No significant associations were found between CHO presence and virulence, though some sub-significant associations merit further study. This work builds our understanding of factors controlling AMR dissemination through the environment and potential health risks.
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Risk of Antibiotic‐Resistant Staphylococcus aureus Dispersion from Hog Farms: A Critical Review
Abstract The World Health Organization has declared antibiotic resistance “one of the biggest threats to global health.” Mounting evidence suggests that antibiotic use in industrial‐scale hog farming is contributing to the spread of antibiotic‐resistantStaphylococcus aureus. To capture available evidence on these risks, we searched peer‐reviewed studies published before June 2017 and conducted a meta‐analysis of these studies’ estimates of the prevalence of swine‐associated, antibiotic‐resistantS. aureusin animals, humans, and the environment. The 166 relevant studies revealed consistent evidence of livestock‐associated methicillin‐resistantS. aureus(MRSA) in hog herds (55.3%) raised with antibiotics. MRSA prevalence was also substantial in slaughterhouse pigs (30.4%), industrial hog operation workers (24.4%), and veterinarians (16.8%). The prevalence of swine‐associated, multidrug‐resistantS. aureus(MDRSA)—with resistance to three or more antibiotics—is not as well documented. Nonetheless, sufficient studies were available to estimate MDRSA pooled prevalence in conventional hog operation workers (15.0%), workers’ household members (13.0%), and community members (5.37%). Evidence also suggests that antibiotic‐resistantS. aureuscan be present in air, soil, water, and household surface samples gathered in or near high‐intensity hog operations. An important caveat is that prevalence estimates for humans reflect colonization, not active infection, and the health risks of colonization remain poorly understood. In addition, these pooled results may not represent risks in specific locations, due to wide geographic variation. Nonetheless, these results underscore the need for additional preventive action to stem the spread of antibiotic‐resistant pathogens from livestock operations and a streamlined reporting system to track this risk.
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- Award ID(s):
- 1316318
- PAR ID:
- 10456200
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- Risk Analysis
- Volume:
- 40
- Issue:
- 8
- ISSN:
- 0272-4332
- Page Range / eLocation ID:
- p. 1645-1665
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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