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

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.

Characterization of Extended Spectrum Β‐Lactamase Producing Enterobacteria and Methicillin‐Resistant Staphylococcus aureus Isolated from Raw Pork and Cooked Pork Products in South China

“…MRSA has been identified in retail foods worldwide. Human infections caused by MRSA take place via direct contact with farm animals or handling of food of animal products (Ye and others ). Pigs are currently regarded as the most important reservoir of livestock‐associated MRSA clones (Sun and others ; Ye and others ).…”

“…Human infections caused by MRSA take place via direct contact with farm animals or handling of food of animal products (Ye and others ). Pigs are currently regarded as the most important reservoir of livestock‐associated MRSA clones (Sun and others ; Ye and others ). A large USA surveys (38 swine herds in 11 states) showed that 77% of pigs investigated were MRSA carriers (Sun and others ).…”

The Prevalence of Antibiotic-Resistant Staphylococcus aureus Nasal Carriage among Industrial Hog Operation Workers, Community Residents, and Children Living in Their Households: North Carolina, USA

“…We examined prevalence of S. aureus , MRSA, and MDRSA nasal carriage outcomes, including several putative markers of LA- S. aureus — scn -negative S. aureus , S. aureus CC398, and S. aureus CC9 (Nadimpalli et al 2015; Rinsky et al 2013; Ye et al 2016a, 2016b)—among adults with occupational exposure to IHOs, adult community resident without occupational exposure to IHOs, and one child < 7 years of age living in the same household as each adult in rural southeastern North Carolina.…”

Livestock-Associated, Antibiotic-Resistant Staphylococcus aureus Nasal Carriage and Recent Skin and Soft Tissue Infection among Industrial Hog Operation Workers

“…movement, coughing, and/or sneezing) [3]. Clonal complex (CC) 398 is the most widely described strain, although CC9 is increasingly reported in Asia [4,5] and the United States [6,7]. Nasal carriage and infection with LA- S .…”