The activity of BMY 28142 a new broad spectrum beta-lactamase stable cephalosporin.

The in-vitro activity of BMY 28142, an iminomethoxy, aminothiazolyl cephalosporin containing a methyl pyrrolidinio C-3 was compared with that of cefotaxime, ceftazidime, aztreonam, imipenem and tobramycin against various bacteria. BMY 28142 was the most active agent tested against the Enterobacteriaceae inhibiting 90% at less than or equal to 1 mg/l. The in-vitro activity of BMY 28142 was equal to or superior to cefotaxime against the highly susceptible members of the Enterobacteriaceae and several-fold superior to ceftazidime and aztreonam. BMY 28142 inhibited many Enterobacter cloacae, Citrobacter freundii and Serratia marcescens resistant to cefotaxime, ceftazidime and aztreonam. BMY 28142 was more active than imipenem against Proteus, Providencia and Morganella species. Ceftazidime and imipenem were more active than BMY 28142 against Pseudomonas aeruginosa, but it inhibited piperacillin and tobramycin-resistant isolates. BMY 28142 inhibited beta-lactamase producing Haemophilus influenzae and Neisseria gonorrhoeae. BMY 28142 was more active than ceftazidime against streptococcal and staphylococcal species, but it did not inhibit or kill most methicillin-resistant Staphylococcus aureus. BMY 28142 did not inhibit most Bacteroides species. BMY 28142 was not hydrolyzed by common plasmid and chromosomal beta-lactamases, but it bound poorly to Enterobacter beta-lactamase, was a poor inhibitor of the TEM plasmid beta-lactamase and was a poor inducer of beta-lactamases.