In-vitro susceptibility of 400 isolates of Neisseria gonorrhoeae in Vancouver, 1982-84

Consecutive isolates of Neisseria gonorrhoeae obtained at a sexually transmitted disease clinic in Vancouver between June 1982 and June 1984 were tested for in-vitro susceptibility to eight antimicrobial agents. Of the 400 isolates 6 (1.5%) were penicillinase-producing N. gonorrhoeae, and for 25 (6.2%) the minimum inhibitory concentrations (MICs) of penicillin were 1.0 to 4.0 micrograms/ml. Ceftriaxone sodium was the most active agent. The MICs were higher than those reported in a Canadian study in 1973-74, except for tetracycline hydrochloride. The patterns of susceptibility of the isolates to one antimicrobial agent correlated significantly with those to each other agent, although the relation was weakest for trimethoprim-sulfamethoxazole and spectinomycin. The results reinforce the need to evaluate local in-vitro susceptibility patterns, especially since the proportion of isolates with relative and absolute resistance to penicillin is increasing.