Melby, K. & Fiegri. A. The in vifro activity of norfloxacin, ofloxacin and ciprofloxacin and other antibiotics in current use against Nrisscv-iu gonorrhome. APMIS 97: 347-350, 1989.One hundred non-beta-lactamase-producing and 50 beta-lactamase-producing strains of Neissrria gonor-rllom~serogroup WI and WII/III were tested in v i m by an agardilution methodagainst apanel of antibiotics includingciprotloxacin. ofloxacin and norfloxacin. All strains irrespective of beta-lactamase production and serogroup allocation. were inhibited by 0.125 mg/l of all quinolones. Ciprofloxacin turned out to be most active followed by ofloxacin and norfloxacin. All strains were also inhibited by low concentrations of cefotaxime (MIC < 0.25 mg/l). Many strains mostly among the beta-lactamase-producing strains were resistant (MIC > 4 mg/l) to doxycycline. Ampicillin isstill activeagainst the majority of non-beta-lactamaseproducing strains. The majority of the strains belonged to serogroup WII/III which are known to be less sensitive to penicillin G and ampicillin.