Penicillinase-producing Neisseria gonorrhoeae in Riyadh, Saudi Arabia.

Of 83 strains of Neisseria gonorrhoeae isolated in Riyadh, Saudi Arabia, between April 1979 and August 1980, 10 produced beta-lactamase and had minimum inhibitory concentrations (MICs) of penicillin between 1 and greater than or equal to 4 micrograms/ml. Of the 73 (88%) non-penicillinase-producing strains, 55% had diminished sensitivity to penicillin (MIC = 0.06 micrograms/ml) and 11 (15%) were highly resistant (MICs ranging from 0.5-2 micrograms/ml). This high incidence of resistance may be due to widespread abuse of antibiotics; it also confirms that two mechanisms of resistance to penicillin exist in this species.