In-vitro activity ofantimicrobial agents against Neisseria gonorrhoeae inBrussels

suMMARY Theminimuminhibitory concentrations (MICs) of18antimicrobial agents against 104 strains ofNeisseria gonorrhoeae isolated intheBrussels areabetween January andOctober 1976have beenmeasured. TheMICsforpenicillin G,ampicillin, amoxycillin, carbenicillin, andcephalexin showed a bimodal distribution. Thesecond modusstrains ofcephalexin (MIC=6-25 ,ug/ml) were relatively resistant topenicillin G (MIC>0'08 ,tg/ml). About51% ofallstrains were relatively resistant topenicillin G,405% toampicillin (MIC>0-16.tg/ml), 46%toamoxycillin, and47'5 % tocarbenicillin. Forcephalexin andcephaloridine, 25% and85% respectively ofallstrains were relatively resistant (MIC> 312jig/ml). Forcefazolin all MICsfell into a rangeof0097-312jig/ml. Resistance totetracycline, doxycycline, minocycine, erythromycin, andspiramycin (MIC> Ig/ml) wasfound in9-5%,7%,6%,365%,and71% respectively ofallisolates. No strains were resistant torifampicin. Forchloramphenicol andthiamphenicol theMICsranged from039to 12-5,ug/ml andfrom0-195 to3-12jig/ml respectively. Theresults forsulphamethoxazole, trimethoprim, andthecombination ofsulphamethoxazole andtrimethoprim ina 20:1ratio aregiven anddiscussed. Thefractional inhibitory concentration (FIC) indices havealsobeencalculated. No ,-lactamase-producing strains were found, anda contingency coefficient C hasbeendetermined forallthepairs ofantibiotics investigated.