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Tigecycline Evaluation Surveillance Trial (TEST) – In vitro antibacterial activity against Gram-positive and Gram-negative pathogens in the United States

Abstract number: 1134_02_5

Bouchillon S., Stevens T., Johnson B., Johnson J., Hoban D., Hackel M., Person M., Dowzicky M.

Background:

Tigecycline, a member of a new class of antimicrobials (glycylcyclines), has been shown to have potent expanded broad spectrum activity against most commonly encountered Gram-positive and Gram-negative species, including anaerobic pathogens responsible for community and hospital infections. The TEST program determined the in vitro activity of tigecycline compared to amikacin, ampicillin, imipenem, cefepime, ceftazidime, ceftriaxone, levofloxacin, minocycline and piperacillin/tazobactam against gram negative rods in addition to linezolid, penicillin and vancomycin for the gram positive species. Isolates were collected from hospitals in the United States throughout 2004.

Methods:

A total of 4100 clinical isolates 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.

Results:

As shown in the table below, tigecycline's activity was similar to imipenem against Enterobacteriaceae. It inhibited multi-resistant ESBL and AmpC producers with a MIC equal or lesser than 2 mcg/ml. Tigecycline also showed in vitro activity with a MIC90 2 mcg/ml against 29 imipenem resistant Enterobacteriaceae strains. Although similar to other classes of broad spectrum antimicrobial agents against non-fermenters, tigecycline was especially active against Acinetobacter spp. with the lowest MIC90 of 2 mcg/ml. Tigecycline inhibited S. aureus with MIC90 of 0.25 mcg/ml for both MSSA and MRSA isolates. Against enterococci, tigecycline's MIC90 was consistent regardless of vancomycin susceptibility.

Conclusion:

Tigecycline's in vitro activity was comparable or greater than most commonly prescribed broad spectrum antimicrobials. The presented data suggest that tigecycline may be an effective and reliable therapeutic option against both susceptible common gram-positive and gram-negative pathogens, including multi-drug resistant strains regardless of degree or type of resistance.

Table for P805

 Enterobacteriaceae (n=2,446)P. aeruginosa (n=390)Acinetobacter spp. (n=261)S. aureus (n=494)Enterococcus spp. (n=509)
RangeMIC50MIC90RangeMIC50MIC90RangeMIC50MIC90RangeMIC50MIC90RangeMIC50MIC90 
Tigecycline0.03–160.25010.25–>1616>160.03–40.520.03–10.120.250.3–0.50.060.12
Amikacin0.5–>6424<=0.5–>6448<=0.5–>64432      
Ampicillin0.5–>32>32>324–>32>32>32<=0.5–>32>32>320.06–>1616>160.25–>161>16
Cefepime0.5–>320.51<=0.5–>32832<=0.5–>3216>32      
Ceftazidime8–>32816<=8–>32<=832<=8–>3232>32      
Ceftriazone0.06–>640.068<=0.06–>64>64>64<=0.06–6464>640.5–>648>641–>64>64>64
Imipenem0.12–>160.510.25–>1618<=0.06–>160.5160.12–>160.250160.25–>161>16
Levofloxacin0.008–>80.068<=0.008–>82>80.015–>88>80.06–>321>320.5–>3232>32
Minocycline0.5–>1628<=0.5–>16>16>16<=0.5–>16180.25–>80.250.250.25–>88>8
Pip/tazobactam0.06–>1281160.12–>1284128<=0.06–>12832>1280.25–>164>160.5–>162>16
Penicillin0.06–>8>8>80.5–>82>8         
Linezolid0.5–4220.5–>822         
Vancomycin0.25–40.510.25–>321>32         

Session Details

Date: 01/08/2007
Time: 00:00-00:00
Session name: XXIst ISTH Congress
Subject:
Location: Oxford, UK
Presentation type:
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