RESUMO
The increase in infections caused by Enterobacterales resistant to carbapenems and other antimicrobials has limited the therapeutic alternatives which have led to the recovery of the use of colistin in clinical practices. Since 2015, a mechanism that confers resistance to colistin through plasmids related to the mcr-1 gene (Mobile Colistin Resistance) was detected, increasing the importance of its susceptibility test in the laboratory. Colistin susceptibility was evaluated by the disk elution method in 24 strains of Carbapenemase-producing type KPC Klebsiella pneumoniae, resulting 4 strains (17 %) resistant to colistin and 20 strains (83 %) intermediate. Also, in these strains, sensitivity to meropenem was evaluated by the E-test® method, finding that 10 strains (41,6 %) were within the acceptable range for their combination with colistin, 5 strains (20, 8 %) were within the uncertain range and 9 strains (37,4 %) were not appropriate for combination with colistin. For the combination of colistin with meropenem to be considered as a therapeutic alternative the MIC of colistin must be ≤ 2 µg /mL with meropenem ≤8 µg /mL, while the MIC between 12-16 µg/mL of meropenem may or not may work; and with a MIC of 32 µg/mL meropenem, the combination is not effective.