Antimicrobial susceptibility of Gram-negative and Gram-positive bacteria collected from Eastern Europe: results from the Tigecycline Evaluation and Surveillance Trial (T.E.S.T.) 2011-2016.

OBJECTIVES: The Tigecycline Evaluation and Surveillance Trial (T.E.S.T.) is a global surveillance program that monitors the in vitro activity of a panel of antimicrobials against clinically important isolates. Data for Gram-positive and Gram-negative isolates collected in Eastern Europe between 2011 and 2016 are presented.

METHODS: MICs were determined by broth microdilution using CLSI guidelines. Antimicrobial susceptibility was determined using European Committee on Antimicrobial Susceptibility Testing breakpoints.

RESULTS: Nine Eastern European countries submitted 4289 isolates. Among Acinetobacter baumannii, resistance to levofloxacin, amikacin and meropenem was 77.5%, 63.4% and 62.2%, respectively. Multidrug resistance (MDR) among A. baumannii was higher in 2015 than previous years (44.1% in 2011, 71.0% in 2015), and then decreased to 51.7% in 2016. The MDR percentage for Pseudomonas aeruginosa was 26.9% and was relatively stable over time. The percentage of extended-spectrum β-lactamase (ESBL)-positive isolates among Escherichia coli and Klebsiella pneumoniae was 20.1% and 55.7%, respectively. Resistance to amikacin, meropenem and tigecycline was low among E. coli and K. pneumoniae and the ESBL-producing subset (≤5.9%). Among Staphylococcus aureus isolates, 36.7% were methicillin-resistant (MRSA); percentages varied year-on-year. No S. aureus isolates, including MRSA, were resistant to linezolid, vancomycin or tigecycline. Among Enterococcus faecium isolates, resistance was 22.6% to vancomycin and 2.3% to linezolid; no isolates were resistant to tigecycline.

CONCLUSION: This study shows low resistance to meropenem and tigecycline among the Enterobacteriaceae, and continued activity of linezolid, vancomycin and tigecycline against Gram-positive organisms. However, antimicrobial resistance continues to be problematic in Eastern Europe and requires continued surveillance.