The present study aimed to compare the MIC values of colistin and polymyxin B in fermentative and non-fermentative Gram-negative bacteria and to examine whether the susceptibility results determined with colistin can be used for polymyxin B.
A total of 268 strains of
Of the 268 strains, 40.7% were found to be colistin resistant and 34% polymyxin B resistant. Essential agreement (EA) and categorical agreement (CA) ratios for all isolates were found to be 81.3% and 85.1%, respectively. Identical MIC values were found for colistin and polymyxin B in 104 isolates (38.8%), and this rate was 31.1% and 48.7% in Enterobacterales and non-fermentative bacteria, respectively. Colistin resistance rates were 25.4% for
According to the results of the study, it was concluded that the MIC values of colistin and polymyxin B antibiotics in all bacteria were not compatible with each other. Colistin susceptibility results cannot be used for treatment with polymyxin B, despite CLSI's recommendation.