Occurrence and Distribution of Antibiotic-Resistant Staphylococcus aureus in a Brazilian Pork Production Chain

Abstract

Here we characterized the distribution and the antibiotic resistance of staphylococci from a Brazilian pork production chain. Samples (n = 1,114) from pig farms, pig lots and slaughterhouses, located in two Brazilian states (Minas Gerais and Paraná), were subjected to coagulase-positive Staphylococcus (CPS) enumeration. S. aureus isolates (n = 251) from this collection were further characterized for their resistance to oxacillin, cefoxitin, vancomycin and tetracycline through phenotypic and molecular assays. CPS counts from pig farms were higher when compared to other samples (P < 0.05). Other counts were relatively low, but present in all production stages. S. aureus isolates were commonly resistant oxacillin and cefoxitin (74.0%, 54/73), qualifying them as methicillin-resistant S. aureus (MRSA), but PCR assays indicated that few harbored the expected antimicrobial-resistance genes ( femB , mecA and mecC ). Vancomycin and tetracycline resistance were identified at lower frequencies (6.8% to 37.0%). Sensitivity (34.5% to 86.7%) and specificity (26.6% to 85.0%) of PCR for detecting antibiotic resistance genes varied based on the assessed antibiotic. Antibiotic resistant staphylococci are widely distributed in the Brazilian pork production chain, and MRSA can become a potential health and economic impediment for the Brazilian pork industry.

Staphylococcus aureus and biofilms: transmission, threats, and promising strategies in animal husbandry

“…S. aureus has been confirmed to be present in air samples, carcasses, and on the surfaces of equipment and tools in slaughter processing lines. During slaughter and processing, S. aureus on the skin of animals and slaughterhouse workers can cross-contaminate pork carcasses and pork products [ 8 ]. Furthermore, S. aureus -induced porcine auricular elephantiasis is common in slaughtered pigs, and this condition increases the risk of S. aureus contamination during pork processing [ 9 ].…”