The isolation and antibiotic resistance patterns of staphylococcus from the skin of humans and livestock using Novobiocin Salt Sucrose Nitrate medium

Novobiocin resistant, coagulase negative staphylococci from the skin of humans and livestock were isolated using Novobiocin Salt Sucrose Nitrate medium (NSSN), and the antibiotic resistance patterns of those isolates were determined. It appears novobiocin resistant bacteria are not common members of the skin's normal flora of either group. From the right ears and arms of 450 Angelo State University volunteers and 20 veterinarians, 28 isolates were recovered with Staphylococcus xylosus being the most prevalent (86%). From the backs and right ears of 93 livestock, including sheep, calves, cows, and steers, 34 isolates were recovered with S. gallinarum being the most common (47%). Resistance to antibiotics such as tetracycline and penicillin was more prevalent in the isolates from humans than livestock. Five S. xylosus isolates from humans, but none from livestock, were resistant to the methicillin substitute oxacillin. These results cast some doubt upon the idea that livestock harbor staphylococcal strains carrying the ancestral MecA gene and thus serve as reservoirs of antibiotic resistance.