Getting ahead of antibiotic-resistant Staphylococcus aureus in U.S. hogs.

Authors

Sarah Rhodes
Elizabeth Christenson
Allie Nguyen
Jesper Larsen
Lance B. Price, George Washington University
Jill Stewart

Document Type

Journal Article

Publication Date

3-4-2021

Journal

Environmental research

Volume

196

DOI

10.1016/j.envres.2021.110954

Abstract

Antibiotic-resistant strains of Staphylococcus aureus, an opportunistic bacterial pathogen, have emerged in industrial livestock operations and agricultural settings. In the United States, there is limited access to industrial livestock operations and farm-level antibiotic use data. As a result, studies often rely on retail meat as a proxy for direct animal sampling. To move beyond this limitation and assess S. aureus colonization in hogs, we purchased the heads of recently-slaughtered hogs and compared S. aureus populations in those raised on industrial hog operations versus those raised without antibiotics. S. aureus isolates were analyzed for antibiotic resistance and putative genotypic markers of livestock adaptation. Although methicillin-resistant S. aureus (MRSA) was not detected in this study, all of the hogs from industrial hog operations (n = 9/9) carried multidrug-resistant S. aureus (MDRSA) with two livestock-adaptation markers (scn-negative and clonal complex (CC) 9 or 398) compared to 11% of hogs raised without antibiotics (n = 1/9). Hogs from industrial operations were 9.0 times (95% confidence interval (CI): 1.4-57.1) as likely to carry livestock-adapted S. aureus and 4.5 times (95% CI: 1.3-15.3) as likely to carry MDRSA as hogs raised without antibiotics. In contrast, the majority of antibiotic-free hogs (67%, n = 6/9) contained human-adapted S. aureus (i.e. scn-positive, CC1) compared to 11% (n = 1/9) of IHO hogs. These results indicate that antibiotic use in IHO hogs may make them more conducive hosts to antibiotic-resistant, livestock-adapted S. aureus strains when compared to hogs raised without antibiotics. Our results are important, as they provide strong evidence that antibiotic use practices influence the S. aureus populations carried by U.S. hogs, supporting the need for increased access to routine monitoring of hog operations for antibiotic resistance management using a One Health framework.

APA Citation

Rhodes, S., Christenson, E., Nguyen, A., Larsen, J., Price, L. B., & Stewart, J. (2021). Getting ahead of antibiotic-resistant Staphylococcus aureus in U.S. hogs.. Environmental research, 196 (). http://dx.doi.org/10.1016/j.envres.2021.110954

Peer Reviewed

1