Tigecycline Evaluation Surveillance Trial (TEST) European in vitro antibacterial activity against selected species of Enterobacteriaceae
Abstract number: 1134_02_8
Johnson B., Bouchillon S., Stevens T., Johnson J., Hoban D., Dowzicky M.
Tigecycline, a member of a new class of antimicrobials (glycylcyclines), has been shown to have potent expanded broad spectrum activity against most species of Enterobacteriaceae as well as gram-positive, atypicals and anaerobes. The TEST program determined the in vitro activity of tigecycline compared to amikacin, ampicillin, imipenem, cefepime, ceftazidime, ceftriaxone, levofloxacin, minocycline and piperacillin/tazobactam against isolates of Enterobacteriaceae collected from hospitals in Germany, Italy, Spain and United Kingdom.
A total of 627 clinical isolates, collected in 2004, 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 NCCLS guidelines.
It was observed that the in vitro activity of all broad spectrum antimicrobial agents still remains highly active against Enterobacteriaceae in Europe. The susceptibility rates for amikacin, cefepime, ceftazidime, ceftriaxone, imipenem, levofloxacin, minocycline, and piperacillin/tazobactam are 99.8%, 94.6%, 84.8%, 87.6%, 100%, 86.1%, 84.5%, and 92.2%, respectively. Tigecycline's activity was similar to the most effective antimicrobial agent, imipenem (100% susceptibility) presenting a MIC50/MIC90 of 0.25/1 mcg/ml against all strains of Enterobacteriaceae. The frequency of ESBL production among K. pneumoniae and E. coli was found to be 21.7% and 2.4%, respectively. Tigecycline inhibited 100% of all ESBL producing E. coli at a MIC of 0.5 mcg/ml and at a MIC of 4 mcg/ml for ESBL producing K. pneumoniae. Approximately 30% of Enterobacter spp. and 6% of Serratia marcescens presented resistance to third generation cephalosporins (ceftazidime and ceftriaxone) suggestive of AmpC-type resistance.
Most of the broad spectrum antimicrobial agents still remain active against European representatives of Enterobacteriaceae. Tigecycline's in vitro activity was comparable to the activities of all broad spectrum antimicrobials with greater activity against ESBL and AmpC producing isolates with a MIC 90 of 2 mcg/ml. The presented data suggest that tigecycline may be an effective and reliable therapeutic option against both susceptible strains of Enterobacterieaceae and multi-drug resistant strains regardless of degree or type of resistance.
|Session name:||XXIst ISTH Congress|
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