Nasal carrier rates and antibiotic resistance of Staphylococcus aureus isolates from hospital and non-hospital populations, Addis Ababa.

Surgical staff of five different hospitals and university biology students were screened for nasal carriage of Staphylococcus aureus: 32.4% of the surgical staff and 21.6% of the students were carriers. The rate for the hospital staff was significantly higher (chi 2 = 9.2, P less than 0.01). The carrier rates among the surgical staff varied between 59.1% for surgeons and 22.7% for other surgical staff. 195 S. aureus strains were isolated: 109 from surgical staff and 86 from students. All were tested for their resistance to antibiotics. Resistance to penicillin was 86.2% and 74.4%, respectively, for hospital and non-hospital isolates. Resistance to erythromycin, gentamicin, kanamycin or co-trimoxazole was not detected among the non-hospital isolates. All isolates were sensitive to vancomycin, cephalothin and clindamycin. Over 96% and 88% of hospital and non-hospital isolates, respectively, were resistant to at least one antibiotic. About 45% of the hospital isolates and 2.3% of the non-hospital isolates showed multiple resistance. The rate of multiple resistance among the hospital staff isolates was considered high and indicative of still higher rates among clinical isolates. Further studies are suggested in order to take appropriate measures against bacterial resistance to antibiotics.