Antimicrobial activity among gram-positive and gram-negative organisms collected from the Asia-Pacific region as part of the Tigecycline Evaluation and Surveillance Trial: Comparison of 2015 results with previous years

We report the in vitro activity of tigecycline and comparators against Gram-negative and Gram-positive organisms collected from Asia-Pacific during 2004-2010 and 2015. MICs were determined by broth microdilution using CLSI guidelines. Antimicrobial susceptibility was assessed using CLSI breakpoints, except for tigecycline FDA breakpoints. For Acinetobacter baumannii, multidrug-resistant (MDR) rates were 81.8% in 2015 and 48.5% during 2004-2010. Among Escherichia coli and Klebsiella pneumoniae respectively, rates of extended-spectrum β-lactamase-producers in 2015 were 24.6% and 15.8%, and during 2004-2010, 21.6% and 23.8%. Pseudomonas aeruginosa MDR rates were 12.7% in 2015 and 18.5% during 2004-2010. For Staphylococcus aureus, 57.1% were methicillin-resistant in 2015 and 46.3% between 2004 and 2010. For Streptococcus pneumoniae, 32.1% were penicillin-resistant in 2015 and 29.9% between 2004 and 2010. Tigecycline MIC90 values were ≤2 mg/L against all species except P. aeruginosa, against which tigecycline is inactive. Antimicrobial resistance in Asia-Pacific is widespread, including a concerning increase in MDR A. baumannii.