Tigecycline Evaluation Surveillance Trial (TEST) United States in vitro antibacterial activity against selected species of Enterococcus spp.
Abstract number: 1134_02_13
Bouchillon S., Stevens T., Johnson B., Johnson J., Hoban D., Hackel M., Person M., Dowzicky M.
Resistance to glycopeptides in enterococci was first recognized in the late 1980s, and since then has been a major challenge to clinicians and infection control. Tigecycline, 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 TEST program determined the in vitro activity of tigecycline compared to vancomycin, linezolid, ampicillin, imipenem, ceftriaxone, levofloxacin, minocycline, penicillin and piperacillin/tazobactam against members of Enterococcus spp. collected from hospitals in the USA.
A total of 509 clinical isolates were identified to the species level at each participating site and confirmed by the central laboratory. Isolates were collected throughout 2004. Minimum Inhibitory Concentration (MICs) were determined by the local laboratory using broth microdilution panels and interpreted according to NCCLS guidelines.
Of 276 E. faecalis evaluated, it was observed resistance to vancomycin in 8 (4.5%) isolates. These isolates were all susceptible to linezolid and tigecycline. Tigecycline presented the lowest MIC50/MIC90 (0.06/0.12 mcg/ml) among all antimicrobial agents evaluated. As a typical profile of E. faecalis, fluoroquinolone (levofloxacin) and tetracycline (minocycline) had limited activities against this species. Among 144 E. faecium, 35 (24.3%) were resistant to vancomycin, of which three isolates were also resistant to linezolid. Tigecycline also presented the lowest MIC50/MIC90 of 0.06/0.12 mcg/ml. Five isolates of vancomycin susceptible E. faecalis and one vancomycin susceptible E. faecium were non-susceptible to linezolid. No abnormal resistance phenotype was observed in other Enterococcus species tested.
Tigecycline's in vitro activity was comparable to or greater than most commonly prescribed antimicrobials. The presented data suggest that tigecycline may be an effective and reliable therapeutic option against Enterococcus spp. including multi-drug resistant strains regardless of degree or type of resistance.
|Session name:||XXIst ISTH Congress|
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