Susceptibility of Neisseria gonorrhoeae to cefotaxime and ceftizoxime.

Two hundred and thirty-nine penicillinase-positive and 240 penicillinase-negative strains of Neisseria gonorrhoeae were tested for their susceptibility to cefotaxime. All were susceptible to cefotaxime at a concentration of 0.062 micrograms/ml. Penicillinase-negative strains were less susceptible than penicillinase-positive strains. This is attributed to the use of prophylactic antibiotics by prostitutes, which has led to the selection of less susceptible penicillinase-negative strains but has not affected the susceptibility of penicillinase-positive strains. The minimum inhibitory concentrations of cefotaxime showed significant positive correlations with those of penicillin, ampicillin, tetracycline, and kanamycin but had a negative correlation with spectinomycin. The related cephalosporin, ceftizoxime, was found to be as effective as cefotaxime against penicillinase-positive and penicillinase-negative gonococci.