Ecology of Staphylococcus aureus and its antibiotic resistance genes in dairy farms: Contributing factors and public health implications

Abstract

Dairy farms are major sources for zoonotic Staphylococcus aureus pathogens and their antibiotic resistance genes. This study was conducted to assess critical sources and factors related to dissemination of S. aureus and its resistance genes within dairy farms in Egypt. In addition, workers' knowledge, attitudes and practices (KAPs) was eval- uated. A total of 102 pooled samples were collected from 3 medium-scale dairy farms in Egypt. S. aureus was detected in 72.5% of the examined samples: lactating cows (72.9%), workers (81.5%), barns environment (88.9%), milking equipment (40%), and bulk tank milk (100%). Cows (udder milk and nostril), workers (hand skin and nostril), barns, open-sides parlor, and lack of acid rinse were associated with S. aureus contami- nation of milking equipment (P= 0.004 - 0.04). Methicillin resistant S. aureus (MRSA, mecA+), vancomycin-resistant S. aureus (VRSA, vanA+) and methicillin-vancomycin-re- sistant S. aureus (MVRSA, mecA+-vanA+) represented 27.5%, 5% and 12.5% of S. au- reus isolates, respectively. This is the first report of MVRSA in dairy farms in Egypt. For workers KAPs, 48.7% didn't know milk-borne zoonoses, while their high risk practices included consumption of raw milk (52.2%), lack of hand wash (48.7%), and willing to work with sore throat (82.6%). This study highlights the critical sources of S. aureus pathogens and their antibiotic resistance genes in dairy farms. This will help in reforming biosecurity plans in dairy farms; an urgent demand for consumers safety in Egypt.