Comparative in-vitro activity of selected new beta-lactam antimicrobials against Neisseria gonorrhoeae.

Four new beta-lactam antimicrobials, ceftriaxone, cefotiam, cefonicid, and mecillinam, were evaluated in vitro against 72 beta-lactamase-negative and 26 beta-lactamase-positive isolates of Neisseria gonorrhoeae. Ceftriaxone was the most active of the antimicrobials tested. It inhibited all isolates, regardless of beta-lactamase activity, at a concentration of less than or equal to 0.015 microgram/ml. Cefotiam and cefonicid were also active against both groups but not as active as ceftriaxone. Both groups of N gonorrhoeae showed a high degree of resistance against mecillinam.