LAUSR

OBJECTIVE Epidemic methicillin-resistant Staphylococcus aureus (MRSA) clones have been described in Ghana, but so far no typical livestock-associated MRSA isolates (CC398) have been found. In this study we provide baseline information on antimicrobial resistance, population structure and virulence gene content of S. aureus isolates from livestock and farm-attendants. METHODS Nasal samples were collected from cattle, pigs, goats, sheep and farm attendants from three farms. S. aureus was identified by MALDI-TOF and antimicrobial susceptibility testing was performed using VITEK II (Biomerieux) and interpreted according to EUCAST guidelines. Whole-genome sequencing was performed using the Illumina MiSeq Platform. RESULTS In total, 401 nasal swab samples were obtained from 57 farm-attendants, 208 pigs, 30 goats, 26 sheep, and 80 cattle. The S. aureus isolates (n = 25) recovered (farm-attendants: n = 10; pigs: n = 8 and goats: n = 7) were frequently resistant to penicillin (68%), tetracycline (44%) and ciprofloxacin (32%); two human isolates were MRSA. Twelve (48%) isolates were multidrug resistant (>3 classes). Genome sequencing of the isolates revealed ST152-t355, ST9-t1430, and ST133-t8662 as dominant clones among farm attendants, pigs, and goats, respectively. The two MRSA isolates detected belonged to ST8-t334 and ST152-t355. The scn and sak genes associated to human-adaption were detected in 10 isolates; nine from humans and one from a goat. Typing results provided evidence of a single potential transmission event (t861, PVL-, scn+). CONCLUSION No MRSA was detected among livestock, maybe due to low intensive farming; however, the relatively high prevalence of MDR isolates may be a result of inappropriate antibiotic usage in Ghanaian livestock production.