title: In vitro synergy of ampicillin and chloramphenicol against gram-negative bacteria.
abstract: The activity of ampicillin and chloramphenicol in combination was evaluated against 16 gram-negative bacterial isolates from the cerebrospinal fluid of neonates with meningitis. The combination of antibiotics was synergistic (fractional inhibitory concentration less than 1.0) against 11 of 16 (69%) isolates by agar dilution technique and 12 of 16 (75%) isolates by microbroth dilution technique. In kinetic studies, ampicillin and chloramphenicol together exhibited an increased rate of killing against 9 of 14 isolates. Antagonistic activity between ampicillin and chloramphenicol was not demonstrated in any of the studies. The clinical evaluation of ampicillin and chloramphenicol together in the treatment of gram-negative neonatal meningitis deserves further study.
mesh_terms: D000667:Ampicillin / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects* / Q000254:growth & development; D002701:Chloramphenicol / Q000494:pharmacology*; D004357:Drug Synergism; D006801:Humans; D007231:Infant, Newborn; D007700:Kinetics; D008826:Microbial Sensitivity Tests
chemical_list: D002701:Chloramphenicol; D000667:Ampicillin