Antimicrobial Susceptibility among European Gram-Negative and Gram-Positive Isolates Collected as Part of the Tigecycline Evaluation and Surveillance Trial (2004-2014)

BACKGROUND: European centers (n = 226) involved in the Tigecycline Evaluation and Surveillance Trial (TEST, 2004-2014) submitted data and bacterial isolates. METHODS: Minimal inhibitory concentrations and susceptibility were determined using Clinical and Laboratory Standards Institute methods and European Committee on Antimicrobial Susceptibility Testing breakpoints. RESULTS: The rates of the following resistant pathogens increased from 2004 to 2014: extended-spectrum β-lactamase (ESBL)-positive Escherichia coli (from 8.9 to 16.9%), multidrug-resistant Acinetobacter baumannii complex (from 15.4 to 48.5%), and ESBL-positive Klebsiella pneumoniae (from 17.2 to 23.7%). The rate of methicillin-resistant Staphylococcus aureus was 27.5% in 2004 and 28.9% in 2014. Resistance to the carbapenems (imipenem and meropenem) was 37.4 and 14.5% for A. baumannii complex and Pseudomonas aeruginosa, respectively. Carbapenem resistance was ≤4.3% among the Enterobacteriaceae and 0.2% against Streptococcus pneumoniae. The resistance to tigecycline ranged between 7.4% against ESBL-producing K. pneumoniae and 0.0% against S. aureus. CONCLUSIONS: The carbapenems and tigecycline were active against Enterobacteriaceae. Agents with activity against A. baumannii complex and P. aeruginosa are limited. The carbapenems, tigecycline, linezolid, and vancomycin were active against Gram-positive organisms.