Beta-lactamase-producing isolates of Neisseria gonorrhoeae in Cape Town

Isolates of Neisseria gonorrhoeae from patients attending the sexually transmitted disease clinics of the Cape Town Municipal Health Department were examined for beta-lactamase (penicillinase) production by a chromogenic cephalosporin test. Of the 208 isolates, 4 (less than 2%) produced beta-lactamase. When grown on chocolate blood agar plates 3 isolates showed no inhibition of growth around a penicillin disc; the 4th had a markedly reduced zone of inhibition. The minimum inhibitory concentrations of penicillin for these 4 strains were from 1 to 4 micrograms/ml.