Evaluation of MIC Colistin in Metallo-beta-lactamase producing Gram negative bacilli by Broth microdilution

Abstract

Introduction: Carbapenemase producing Enterobacterales and nonfermenter organisms like aeruginosa and sp. cause difficult to treat life treating infections. Colistin plays important role in treating such infection. Broth microdilution is recommended by EUCAST and CLSI for MIC determination of colistin.
Materials and Methods: Gram negative bacilli resistant to Imipenem were subjected to test for Metallo-beta-lactamase (MBL) production by Disc potentiation test. MIC determination of colistin was done by Broth microdilution (BMD) in MBL producing isolates.
Result: 20.5% of isolates of , sp., and sp. were found to be MBL producers. All were sensitive to colistin. 1 isolate of sp. and sp. each were found to be resistant. 3 isolates of Acinetobacter sp. were resistant to colistin.
Conclusion: MBL producing Enterobacterales and nonfermentors like sp. showed good sensitivity to colistin. sp. showed 17.64% resistance to colistin.