PREVALENCE OF METHICILLIN-RESISTANT STAPHYLOCOCCI AND SUSCEPTIBILITY TO ANTIMICROBIAL AGENTS IN RIYADH, SAUDI-ARABIA

Surveillance data reported by hospitals participating in this study de monstrated that 5% of Staphylococcus aureus and 35% of Strephylococcus epidermidis isolates were resistant to methicillin. Two hundred clini cal isolates of methicillin-resistant staphylococci (MRS) (100 each of S aureus and S epidermidis) were tested for susceptibility to 16 anti microbial agents by the disk diffusion technique as recommended by the National Committee for Clinical Laboratory Standards. The isolates sh owed a high frequency of resistance to tetracycline and aminoglycoside s. The incidence of resistance was higher in S aureus than in S epider midis, especially for beta-lactam antibiotics and aminoglycosides. All isolates were susceptible to vancomycin, and only 3% of methicillin-r esistant S aureus (MRSA) and 2% of methicillin-resistant S epidermidis (MRSE) were resistant to fucidin whereas 90% of MRSA and 82% of MRSE were resistant to gentamicin. Most of the MRSE isolates were susceptib le to cefamandole and cephalothin but. few were susceptible to ceftria xon.