title: Bacteriological studies with ampicillin/sulbactam on selected strains of gram-negative bacteria.
abstract: Antibacterial activity of sulbactam or ampicillin alone and in combination on ampicillin-resistant, beta-lactamase-producing Gram-negative bacteria (Citrobacter freundii and Escherichia coli) was studied. Inhibition of beta-lactamase activity by sulbactam was investigated using intact and disrupted cells. Minimal inhibitory concentrations of ampicillin were high but decreased significantly in the presence of sulbactam. Similar enzyme inhibition was observed with intact and disrupted bacterial cells, thus indicating efficient penetration by sulbactam into the periplasmic space. Bacterial killing was achieved in approximately 4 hrs with ampicillin/sulbactam at concentrations that neither killed nor inhibited the same strains when the drugs were used alone. Sulbactam was more effective against plasmid-cured strain of E. coli than the same plasmid-containing organism.
authors.affiliation: Departamento de Microbiologia, Facultad de Ciencias biologicas y de Recursos Naturales, Universidad de Concepcion, Chile.
authors.forename: H
authors.initials: H
authors.lastname: Bello
authors.forename: E
authors.initials: E
authors.lastname: del Solar
authors.forename: C
authors.initials: C
authors.lastname: González
authors.forename: A
authors.initials: A
authors.lastname: Garcia
authors.forename: R
authors.initials: R
authors.lastname: Urrea
authors.forename: R
authors.initials: R
authors.lastname: Zemelman
mesh_terms: D000667:Ampicillin / Q000494:pharmacology*; D002954:Citrobacter / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D004347:Drug Interactions; D004926:Escherichia coli / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D010957:Plasmids; D013407:Sulbactam / Q000494:pharmacology*; D065093:beta-Lactamase Inhibitors; D001618:beta-Lactamases / Q000235:genetics
chemical_list: D065093:beta-Lactamase Inhibitors; D000667:Ampicillin; D001618:beta-Lactamases; D013407:Sulbactam