Evaluation of in vitro activity of tigecycline and ten comparators against methicillin-resistant Staphylococcus aureus from 34 countries: TEST Program 2004–2006

Abstract number: 1733_1549

Badal R., Bouchillon S., Hackel M., Johnson J., Hoban D., Johnson B., Dowzicky M.

Background: Tigecycline (TIG), a member of a new class of antimicrobials (glycylcyclines), has been shown to have potent expanded broad spectrum activity against most commonly encountered species responsible for community and hospital acquired infections. The T.E.S.T. Program determined the in vitro activity of TIG compared to amoxicillin-clavulanic acid, piperacillin-tazobactam, levofloxacin, ceftriaxone, linezolid (LZD), minocycline (MIN), and vancomycin (VAN), ampicillin, penicillin and imipenem against methicillin-resistant S. aureus (MRSA) isolates collected from 272 sites in 34 countries throughout 2004–2006.

Methods: A total of 2,669 clinical isolates of MRSA were identified to the species level at each participating site and confirmed by the central laboratory. Minimum Inhibitory Concentration (MICs) were determined by the local laboratory using supplied broth microdilution panels and interpreted according to CLSI guidelines, except for tigecycline, which used the susceptible breakpoint <0.5 mg/mL for S. aureus (including MRSA) as defined in the FDA approved package insert.

Results: The %S for the study drugs with MRSA activity – TIG, VAN, LZD, and MIN – was 100, 100, 100, and 97.6 respectively. There were few significant differences among geographic regions, except for lower activity of MIN in Asia (%S = 80.4) and the Middle East (%S = 13.3) compared to Europe (97.3%) and North America (99.1%). IMP showed a broad range of MIC50 results, with North America and Europe at the low end (0.5 and 2 mg/mL, respectively), and all others ≥16 mg/mL. TIG inhibited 100% of strains in all regions. MIC50/90 (mg/mL) for TIG, VAN, LZD, and MIN were 0.12/0.25, 1/1, 2/2, and ≤0.25/2, respectively.

Conclusions: Global susceptibility patterns of MRSA remain fairly consistent. TIG was as potent as VAN and LZD, inhibiting 2,669/2,669 (100%) of the MRSA isolates at their respective breakpoints. TIG's excellent expanded broad spectrum of activity against MRSA should make it a very useful drug in treatment of difficult staphylococcal infections.

Session Details

Date: 31/03/2007
Time: 00:00-00:00
Session name: European Society of Clinical Microbiology and Infectious Diseases
Location: ICC, Munich, Germany
Presentation type:
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