The performance of mainstream commercial antimicrobial susceptibility testing systems on polymyxins has not been well evaluated in China. In this study, three antimicrobial susceptibility testing systems were evaluated for polymyxin B and colistin.
The MICs of 257 Gram-negative strains collected from clinical cases and livestock were determined and analyzed. Using Broth Microdilution as the gold standard, the performance of VITEK 2® COMPACT, PhoenixTM M50, and Bio-kont AST System were evaluated. Essential agreement (EA), category agreement (CA), very major error (VME), and major error (ME) were calculated for comparison. The results of
The EA, CA, VME, and ME to polymyxin B for Bio-kont were 83.5, 95.6, 13.1, and 0.6%, respectively. The EAs, CAs, VMEs, and MEs to colistin were as follows: Bio-kont, 86.7%/96.5%/7.2%/1.7%; Vitek 2, 64.2%/86.8%/41.0%/0%, and Phoenix M50, 92.9%/92.9%/21.7%/0%. The performance of Bio-kont to polymyxin B and colistin for
With relatively more accurate results for polymyxin B and colistin and lower VME, Bio-kont has an advantage in polymyxin antimicrobial susceptibility testing, especially for