Article

Improved antimicrobial activity of linezolid against vancomycin-intermediate Staphylococcus aureus.

Department of Infection Control Science, Department of Bacteriology, Faculty of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-Ku, Tokyo, Japan 113-8421.
Antimicrobial Agents and Chemotherapy (Impact Factor: 4.45). 09/2008; 52(11):4207-8. DOI: 10.1128/AAC.00676-08
Source: PubMed

ABSTRACT Linezolid has been used for the treatment of nosocomial and community-acquired pneumonia as well as complicated skin and soft tissue infection caused by methicillin-resistant Staphylococcus aureus (MRSA) including vancomycin-intermediate S. aureus (VISA) (5, 10, 12). ...

0 Followers
 · 
124 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Vancomycin-intermediate Staphylococcus aureus (VISA) and its precursor hetero-VISA (hVISA) were discovered almost 20 years ago and have continued to be a stumbling block in the chemotherapy of meticillin-resistant S. aureus (MRSA). Unlike vancomycin resistance mediated by the van gene in enterococci and staphylococci, VISA is generated by accumulation of mutations. It displays diverse and intriguing genetic mechanisms underlying its resistance phenotype. Here we make a brief note on our recent understanding of the genetics of hVISA, VISA and the newly discovered phenotype ‘slow VISA’ (sVISA).
    06/2014; DOI:10.1016/j.jgar.2014.04.006
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this study, the impact of inoculum density on the growth inhibitory and killing activities of oritavancin and comparators (vancomycin, daptomycin and linezolid) in vitro against four Staphylococcus aureus strains at clinically relevant drug concentrations was studied. Broth microdilution and time-kill assays were performed using a standard inoculum [ca. 10(5)colony-forming units (CFU)/mL as per Clinical and Laboratory Standards Institute (CLSI) guidelines] and a high inoculum (ca. 10(7)CFU/mL). Whereas minimal inhibitory concentrations (MICs) of comparators were 2-8-fold higher when tested at high inoculum, oritavancin MICs were 16-fold higher for all strains at the high inoculum relative to the standard inoculum. However, in time-kill assays, when tested at its fC(min) [trough concentration of free (non-protein-bound) drug] and fC(max) (peak concentration of non-protein-bound drug), oritavancin retained its bactericidal activity against a vancomycin-susceptible, meticillin-susceptible S. aureus (VS-MSSA) strain and a vancomycin-susceptible, meticillin-resistant S. aureus (VS-MRSA) strain both at standard and high inocula. At its fC(max), oritavancin was bactericidal at standard inoculum but not at high inoculum against two vancomycin-intermediate S. aureus (VISA) strains. Against both VISA strains at standard inoculum, oritavancin at its fC(min) reduced cell density by between 2 and 3 log (bacteriostatic), predicting that it will retain activity against certain VISA infections. However, oritavancin had no substantial growth inhibitory effect against either VISA strain at high inoculum, suggesting that in rare VISA infections with an anticipated high bacterial burden such as endocarditis, alternative oritavancin dosing strategies, including combinations with other agents, may be explored.
    International journal of antimicrobial agents 11/2011; 39(2):159-62. DOI:10.1016/j.ijantimicag.2011.09.017 · 4.26 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The in vitro activities of newer agents against 569 methicillin-resistant Staphylococcus aureus (MRSA) blood isolates stratified by vancomycin MIC values (≤1 versus >1 μg/mL) were evaluated using broth microdilution methods. All agents had good in vitro activities against MRSA regardless of vancomycin MIC values. Some significant correlations between vancomycin and newer agents' MIC values were observed.
    Diagnostic microbiology and infectious disease 05/2012; 73(3):264-6. DOI:10.1016/j.diagmicrobio.2012.01.015 · 2.57 Impact Factor

Full-text (4 Sources)

Download
68 Downloads
Available from
Jun 4, 2014