Livestock-associated methicillin and multidrug resistant S. aureus in humans is associated with occupational pig contact, not pet contact.

Xiaohua Ye,Zhenjiang Yao,Sidong Chen,Junli Zhou,Xiaolin Wang,Weidong Liu,Haifeng Yu,Yanping Fan

doi:10.1038/srep19184

Xiaohua Ye, Zhenjiang Yao + Show 6 more

Open Access

https://doi.org/10.1038/srep19184

Copy DOI

Abstract

This study aimed to explore the association of livestock-associated S. aureus with occupational pig contact and pet contact. In this cross-sectional study, 1,422 participants (including 244 pig workers, 200 pet-owning workers and 978 control workers) responded to a questionnaire and provided a nasal swab for S. aureus analysis. Resulting isolates were tested for antibiotic susceptibility, the immune evasion cluster (IEC) genes, and multilocus sequence type. Compared with controls, the pig workers demonstrated a greater prevalence of multidrug-resistant S. aureus (MDRSA) [prevalence ratio (PR) = 3.38; 95% CI: 2.07–5.53] and methicillin-resistant S. aureus (MRSA) (PR = 7.42; 95% CI: 3.71–14.83), but the prevalence of MDRSA and MRSA was similar in pet-owning workers and controls. There was a positive relation of frequency of pig contact with prevalence of MDRSA and MRSA carriage. Only pig workers carried MDRSA CC9 (16 isolates) and MRSA CC9 (16 isolates), and all of these isolates were tetracycline resistant and absent of IEC genes. These findings suggest that livestock-associated MRSA and MDRSA(CC9, IEC-negative, tetracycline-resistant) in humans is associated with occupational pig contact, not pet contact, and support growing concern about antibiotics use in pig farms and raising questions about the potential for occupational exposure to opportunistic S. aureus.

Highlights

This study aimed to explore the association of livestock-associated S. aureus with occupational pig contact and pet contact
The most striking finding from this study was that pig workers carried methicillin-resistant S. aureus (MRSA) and multidrug-resistant S. aureus (MDRSA) isolates with multiple markers of livestock-association, while pet-owning workers and controls were not observed to be carrying these livestock-associated isolates
Pig workers had a significantly higher prevalence of both MDRSA and MRSA than controls, but the prevalence of MDRSA and MRSA was similar in pet-owning workers and controls

Summary

Introduction

This study aimed to explore the association of livestock-associated S. aureus with occupational pig contact and pet contact. Pig workers carried MDRSA CC9 (16 isolates) and MRSA CC9 (16 isolates), and all of these isolates were tetracycline resistant and absent of IEC genes These findings suggest that livestock-associated MRSA and MDRSA(CC9, IEC-negative, tetracycline-resistant) in humans is associated with occupational pig contact, not pet contact, and support growing concern about antibiotics use in pig farms and raising questions about the potential for occupational exposure to opportunistic S. aureus. Studies have defined livestock-associated S. aureus based on CCs and resistance pattern[4,13], while few have incorporated recent evidence suggesting that absence of the human-specific immune evasion cluster (IEC) genes (such as scn, chp, sak, and sea) may be useful markers of livestock association. The IEC genes may be useful to differentiate livestock-to-human transmission from community-acquired human colonization

Objectives

Results

Conclusion