IN-VITRO ACTIVITY OF THE TRICYCLIC BETA-LACTAM GV104326

GV104326 is a novel tricyclic beta-lactam (a trinem or, formerly, trib actam). The in vitro activity of GV104326 was compared with those of c efuroxime, cefixime, amoxicillin, amoxicillin-clavulanic acid, cefpiro me, and ciprofloxacin. GV104326 had in vitro activity generally simila r to that of cefixime against members of the family Enterobacteriaceae (MIC at which 90% of the isolates are inhibited [MIC(90)], less than or equal to 2 mu g/ml), with cefuroxime and amoxicillin-clavulanic aci d being 8- to 32-fold less active and with cefpirome being 4- to 8-fol d more active against members of this family. The trinem had no activi ty against Pseudomonas aeruginosa or Stenotrophomonas maltophilia (MIC (90) >128 mu g/ml) but was the most active agent against Acinetobacter calcoaceticus. GV104326 was particularly active against gram-positive cocci. Ninety percent of methicillin-susceptible Staphylococcus aureu s strains were susceptible to 0.03 mu g of GV104326 per ml, making it the most active agent studied. Enterococci and Lancefield group A and B streptococci were generally equally or somewhat more susceptible to GV104326 than they were to amoxicillin. Streptococcus pneumoniae strai ns mere highly susceptible to GV104326, and those strains which showed decreased susceptibility to penicillin were generally twofold more su sceptible to the trinem than to amoxicillin. Haemophilus influenzae an d Moraxella catarrhalis were highly susceptible to GV104326 (MIC(90)s, 0.12 and 0.03 mu g/ml, respectively). The anaerobes Clostridium perfr ingens, Bacteroides fragilis, and Peptostreptococcus spp. were more su sceptible to the trinems (formerly tribactams) than to the other agent s studied.