INVITRO ACTIVITY OF BAY V3522, A NEW CEPHALOSPORIN, COMPARED WITH ACTIVITIES OF OTHER AGENTS

The in vitro activity of Bay v 3522, a new aminobenzothiazol cephem, was compared with those of other oral β-lactams. Bay v 3522 displayed high activity against Staphylococcus spp. (MICs for 90% of strains tested [MIC90s], 0.5 μg/ml), Streptococcus pneumoniae (MIC90, 0.06 μg/ml), and Haemophilus influenzae and Branhamella catarrhalis (MIC90s, 2 μg/ml). There was limited activity against members of the family Enterobacteriaceae, with the MIC90s being between 4 and > 128 μg/ml. The stability of Bay v 3522 to hydrolysis by the SHV-1 and TEM-1 enzymes was intermediate to those of cephalexin (least hydrolyzed) and cefaclor, but it was markedly more stable than amoxicillin. There was high affinity of the chromosomally mediated P99 enzyme. The protein binding of Bay v 3522 was 45%. The primary target of Bay v 3522 was penicillin-binding protein 3.