A Longitudinal Analysis of Antimicrobial Susceptibility in Clinical Institutions in Germany as Part of the Tigecycline Evaluation and Surveillance Trial (2004–2007)

Abstract

Background: The Tigecycline Evaluation and Surveillance Trial (T.E.S.T.) global surveillance program has been designed to assess the in vitro activity of the broad-spectrum antimicrobial agent tigecycline plus several comparative agents. Methods: In vitro activities of bacterial isolates obtained from 13 centers in Germany between 2004 and 2007 were evaluated longitudinally and pooled, using the interpretive criteria of the European Committee on Antimicrobial Susceptibility Testing (EUCAST). Results: Tigecycline demonstrated good activity against both Gram-positive and -negative pathogens monitored in this study [minimum inhibitory concentration (MIC) required to inhibit the growth of 90% of organisms (MIC₉₀) 0.06–2 μg/ml] with the exception of Pseudomonas aeruginosa, which had elevated MICs for most antimicrobial agents. Imipenem and meropenem also showed good activity (MIC₉₀ ≤0.06–4 μg/ml) against most Gram-negative pathogens but were less active against Gram-positive organisms (MIC₉₀ ≤0.12 to ≥32 μg/ml). Conclusions: Tigecycline was highly active against most pathogens monitored in the T.E.S.T. study. A low tigecycline MIC₉₀ was reported against Acinetobacter baumannii and drug-resistant Enterococcus faecium,Staphylococcus aureus and Escherichia coli. The carbapenems showed the lowest MIC₉₀ values against extended-spectrum β-lactamase-positive E. coli. E. coli susceptibility to most antimicrobial agents decreased over the course of this study.