Spectrum and potency evaluation of a new oxazolidinone, linezolid: report from the SENTRY Antimicrobial Surveillance Program, 1998-2000.
Resistance (R) among Gram-positive cocci has escalated in the last two decades to levels necessitating the development and use in the newer drug classes, oxazolidinones (linezolid) and streptogramins (quinupristin/dalfopristin [Q/D]). The SENTRY Antimicrobial Surveillance Program has monitored these classes before, during and after their release by various regulatory agencies. Over 30,000 Gram-positive strains were tested against >30 drugs by reference broth microdilution methods between 1998-2000 in four geographic regions (Asia-Western Pacific [APAC], Europe [EU], Latin America [LA], North America [NA]). The tested strains were 23,188 staphylococci; 5,103 enterococci and 2,045 streptococci. Among staphylococci, linezolid was active against all isolates (MICs, < or =4 microg/ml) regardless of susceptibility patterns of other antimicrobial agents. Similar results were noted for vancomycin (includes one VISA from Hong Kong), teicoplanin, and Q/D (<1% R). Gatifloxacin had the widest spectrum among fluoroquinolones (FQ) against Staphylococcus aureus (1.5-9.2% R) and coagulase-negative staphylococci (0.8-4.0%). Linezolid was also active against all enterococci (MIC50 and (90,) 2 microg/ml). Q/D was active against only 75.3% of vancomycin-resistant enterococci (VRE). The VRE rate was highest in NA (12.4%) > EU (3.2%) > LA (1.6%) > APAC (1.3%). Among streptococci, linezolid was consistently active (MIC(90,) 1 microg/ml) as were the glycopeptides and Q/D. Variable penicillin-R (MIC, > or = 2 microg/ml) was observed among regions: EU (32.5%) > APAC (15.1%) > LA (13.8%) > NA (9.6%), and macrolide-R was higher in EU (40.3%). Ciprofloxacin-R at > or =4 microg/ml in streptococcal strains was noted world wide highest in viridans group streptococci (18.4-25.6%). Linezolid remained active (MIC, < or =4 microg/ml) against all Gram-positive species strains tested in the SENTRY Program (1998-2000). Q/D, glycopeptides and newer FQ compounds were generally less effective in vitro. It remains a prudent practice to continue surveillance programs to detect emerging resistance patterns and recognize significant regional variations in the oxazolidinone susceptibilities.
Mutnick
Alan H
AH
The JONES Group/JMI Laboratories, North Liberty, Iowa, USA. alan-mutnick@jmilabs.com
Biedenbach
Douglas J
DJ
Turnidge
John D
JD
Jones
Ronald N
RN
D000081:Acetamides / Q000494:pharmacology*; D000569:Americas; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001208:Asia; D002455:Cell Division / Q000187:drug effects; D024881:Drug Resistance, Bacterial; D005060:Europe; D006090:Gram-Negative Bacteria / Q000187:drug effects* / Q000502:physiology; D006094:Gram-Positive Bacteria / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D000069349:Linezolid; D008826:Microbial Sensitivity Tests; D023303:Oxazolidinones / Q000494:pharmacology*; D013379:Substrate Specificity; D013997:Time Factors
D000081:Acetamides; D000900:Anti-Bacterial Agents; D023303:Oxazolidinones; D000069349:Linezolid