Determination of an Inoculum Effect with Various Cephalosporins among Clinical Isolates of Methicillin-Susceptible Staphylococcus aureus

Authors

Esteban C Nannini
Martin E Stryjewski
Kavindra V Singh
Tom H Rude
G Ralph Corey
Vance G Fowler
Barbara E Murray

Publication Date

5-1-2010

Journal

Antimicrobial Agents and Chemotherapy

Abstract

Using 98 clinical methicillin-susceptible Staphylococcus aureus isolates of known beta-lactamase (Bla) type, we found a pronounced inoculum effect for cephalexin (mostly Bla type A and C strains), a mild inoculum effect for cephalothin (especially types B and C), and no inoculum effects for ceftriaxone and cefuroxime. Ceftobiprole showed the lowest MICs at a high inoculum but with a slight increase for Bla-positive versus Bla-negative strains. Since a potential therapeutic effect associated with a cephalosporin inoculum effect has been described, further studies are warranted.

Keywords

Anti-Bacterial Agents, Ceftriaxone, Cefuroxime, Cephalexin, Cephalosporins, Cephalothin, Humans, Methicillin, Microbial Sensitivity Tests, Staphylococcal Infections, Staphylococcus aureus

DOI

10.1128/AAC.01325-09

PMID

20211890

PMCID

PMC2863656

PubMedCentral® Posted Date

March 2010

PubMedCentral® Full Text Version

Post-print

Published Open-Access

yes