title: Importance of inoculum growth phase when using an in vitro pharmacokinetic model to evaluate beta-lactam antibiotics.
abstract: The bactericidal activity of cefuroxime, cephaloridine and cephalexin is evaluated in an in vitro model. The inocula are derived from an overnight static culture, or after a pre-incubation period of 1 or 2 hours to allow cell re-growth. The early bactericidal effect of the antibiotics is more evident using pre-incubated cells, especially for Staphylococcus aureus 663. At hour 8, with Escherichia coli 851/E, there is re-growth using the static inoculum, while the antibiotic effect is still evident using the pre-incubated one. The importance arises therefore for considering the phase of growth of the inoculum as a critical parameter when using in vitro models with varying concentrations of beta-lactam antibiotics.
authors.affiliation: Glaxo-Duncan Research Laboratories, Verona, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Xerri
authors.forename: R
authors.initials: R
authors.lastname: Broggio
authors.forename: B
authors.initials: B
authors.lastname: Caro
authors.forename: P
authors.initials: P
authors.lastname: Scheda
mesh_terms: D000900:Anti-Bacterial Agents / Q000493:pharmacokinetics*; D002444:Cefuroxime / Q000493:pharmacokinetics; D002506:Cephalexin / Q000493:pharmacokinetics; D002509:Cephaloridine / Q000493:pharmacokinetics; D004926:Escherichia coli / Q000187:drug effects* / Q000254:growth & development; D008826:Microbial Sensitivity Tests; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000254:growth & development
chemical_list: D000900:Anti-Bacterial Agents; D002509:Cephaloridine; D002444:Cefuroxime; D002506:Cephalexin