C2-3870. Comparative In Vitro Activity of Tigecycline Against Clinical Acinetobacter baumannii Isolates: Results of the German TEST (G-TEST) Surveillance Program, 2005-2007
Session: Poster Session: Acinetobacter: Global Impact
Tuesday, October 28, 2008: 12:00 AM
Room: Hall C
Background: A. baumannii (ABA) is an important pathogen causing nosocomial infections, particularly in the compromised host. Tigecycline (TGC), which has been shown to have potent activity against a wide range of bacteria including Acinetobacter spp., has been introduced in Germany in May 2006. G.-T.E.S.T. is an ongoing surveillance program comprising 15 laboratories monitoring the susceptibility of bacterial pathogens to TGC. The objective of this study was to evaluate the in vitro susceptibilities of both ICU and non-ICU isolates of ABA to TGC and comparators. Methods: A total of 257 isolates collected during 2005 (n=140) and 2007 (n=117), of which 86 and 160 isolates were ICU isolates and non-ICU isolates, respectively (11 unknown), was included. Agents tested were TGC, doxycycline (DOX), ceftazidime (CAZ), ciprofloxacin (CIP), gentamicin (GEN), imipenem (IMP) and other drugs. MICs were determined by broth microdilution in a central laboratory and interpreted by EUCAST criteria, if available. Results: MIC50/90 values of TGC, DOX, CAZ, CIP, GEN and IMP were 0.25/1, <0.25/8, 4/>64, 0.25/>16, 1/>32 and 0.5/8 mg/L for ICU isolates compared to 0.25/1, <0.25/2, 4/32, 0.25/>16, 1/4 and 0.5/1 mg/L for non-ICU isolates. Overall, 71% and 92% of isolates were susceptible to CIP and IMP, respectively. Susceptibility to IMP decreased from 98% in 2005 to 85% in 2007, while susceptibility to CIP remained unchanged. TGC was the most active drug inhibiting all isolates at <4 mg/L. In terms of MIC90s, TGC (1 mg/L) was 2 times more active than DOX or IMP. Conclusions: TGC demonstrated very good in vitro activity against the tested ICU and non-ICU isolates of ABA. TGC seems to be a promising drug for the treatment of infections caused by this pathogen.
Barbara Körber-Irrgang, PhD, Antiinfectives Intelligence GmbH, Eva Leitner, MD, Wyeth Pharma GmbH, Harald Seifert, PhD, Dept of Microbiology, University of Cologne, Michael Kresken, PhD, Antiinfectives Intelligence GmbH, Rheinbach, Germany and  H. Seifert,
Wyeth Role(s): Research Contractor, Received: Research Grant.

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