[In vitro activity of ampicillin and ampicillin-sulbactam on diverse bacteria].

A foremost mechanism of bacterial resistance to penicillin and its derivatives is the chromosomal or plasmid mediated production of B-lactamase. Inhibitors of these enzymes like sulbactam may help overcome this problem. We tested the in vitro activity of ampicillin alone or in association with sulbactam (1:1 ratio) against enterobacteriaceae, aeromonae, Hemophilus influenzae, staphylococci and Streptococcus fecalis, isolated from patients suffering different infectious diseases. The Kirby-Bauer method was used to evaluate susceptibility and MIC was determined by agar dilution techniques. Most enterobacteriaceae and aeromonae were resistant to ampicillin. The association was effective against shigellae and Yersinia enterocolitica. 28% of H. influenzae strains were resistant to ampicillin alone but were susceptible to the association. 30% of resistant staphylococci became sensitive to the association.