title: Impact of inoculum size and heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) on vancomycin activity and emergence of VISA in an in vitro pharmacodynamic model.
abstract: The activity of vancomycin against heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) and non-hVISA isolates, using an in vitro pharmacodynamic model, was reduced in the presence of a high inoculum amount (10(8) CFU/ml). A high bacterial load of >10(5) CFU/ml persisted for all strains with doses up to 5 g every 12 h against high inoculum amounts. No change in the vancomycin MIC was detected in any isolate at a moderate inoculum amount (10(6) CFU/ml), and bactericidal activity occurred only against the non-hVISA isolate (time to 99% kill, 7.5 h; P = 0.001).
authors.affiliation: Department of Pharmacy Practice, Eugene Applebaum College of Pharmacy and Health Sciences, Detroit, Michigan 48201, USA.
authors.forename: Warren E
authors.initials: WE
authors.lastname: Rose
authors.forename: Steven N
authors.initials: SN
authors.lastname: Leonard
authors.forename: Kerri L
authors.initials: KL
authors.lastname: Rossi
authors.forename: Glenn W
authors.initials: GW
authors.lastname: Kaatz
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Rybak
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D015169:Colony Count, Microbial; D003198:Computer Simulation; D006801:Humans; D008826:Microbial Sensitivity Tests; D013203:Staphylococcal Infections / Q000382:microbiology; D013211:Staphylococcus aureus / Q000187:drug effects*; D014640:Vancomycin / Q000494:pharmacology*; D020713:Vancomycin Resistance / Q000187:drug effects*
chemical_list: D000900:Anti-Bacterial Agents; D014640:Vancomycin