Nasal carriage and antibiotic resistance of Staphylococcus aureus isolates from hospital and non-hospital personnel in Abha, Saudi Arabia.

The prevalence of nasal carriage of Staphylococcus aureus, antibiograms and prevalence of methicillin-resistant S. aureus (MRSA) were studied in 1999 among healthy hospital and non-hospital personnel in Abha, Saudi Arabia. S. aureus was isolated from 26.1% of 299 adults in the community and 25.4% of 279 hospital personnel. No isolate was resistant to vancomycin. Antibiotic resistance rates, for all other antibiotics tested except cephalothin, were significantly higher for strains from hospital personnel (P values < 0.001-0.04) compared to non-hospital adults. The antibiograms were also compared with those of 140 clinical isolates. The rates of resistance of the inpatient strains to all the antibiotics tested were significantly higher than those of hospital nasal carrier strains (P < 0.001-0.05). MRSA was isolated, respectively, from 5.1% and 18.3% of non-hospital and hospital carriers; MRSA carriage rates were 1.3% and 4.7%, respectively, for non-hospital and hospital carriers, and 61% of S. aureus isolates from infected patients were MRSA. Only 8% of non-hospital but 44% of hospital carrier strains were multiply resistant (P < 0.001). Multiple resistance among inpatient strains (89%) was significantly higher than that among hospital nasal strains (44%) (P < 0.001). Such rates of multiple resistance and endemic MRSA prevalence among healthy carriers (11%) at a much higher rate than those reported in the literature should raise concern in a region with unrestricted availability of antibiotics.