Antibiotic resistance and molecular characteristics of Staphylococcus aureus isolated from pigs in Hunan, China

Staphylococcus aureus (S. aureus) has been recognized as one of the important zoonotic pathogens. However, it was limited about the epidemiology and genetic characteristics of S. aureus isolated from pigs in Hunan province, china. The aim of this study was to determine the characteristics of 163 S. aureus isolated from 590 pigs in Hunan Province, China. All isolates were characterized by agr typing, detection of virulence genes and antibiotic resistance genes, lethal test of mice and antibiotic susceptibility tests. The results showed that 30 strains of the 163 isolates were divided into agrⅠ (18.40%), agrⅡ(36/163, 22.09%), agrⅢ (20/163, 12.27%,), agr Ⅳ(20/163,12.27%) and the remaining 57 isolates were amplified negative by agr primers. In the 163 isolates, the detection rate of the virulence genes hlb, hld, hla, icaA, seb, fnbA, eta, etb, sea, tst and pvl ranged from 2.45% to 100%. The 43 isolates that were lethal to the mice, had β-hemolytic activity, the number of virulence genes of which was 7.8% higher than that of the remaining 120 non-fatal strains. The resistance rates of the 163 isolates to the 15 antibiotics were 0% (0/163) - 100% (163/163). All isolates were susceptible to Vancomycin and only 7 isolates were methicillin - resistant S. aureus (MRSA). The detection rates of the 11 resistance genes was 0% (0/163) - 100% (163/163). This study first to describes the epidemiology and characteristics of S. aureus from pigs in Hunan Province, which will help in tracking the evolution of epidemic strains and preventing pig-human transmission events.