Correlation of Mic by Vitek and Bmd of Colistin in Carbapenem Resistant Enterobacteriaceae Isolated from Cancer Pateints in Oncology Centre

Abstract

The purpose of this research is to determine correlation between MIC of Colistin by Vitek 2 compact and BMD in CRE strains isolated from cancer patients and determine its applicability in oncology hospital. All CREs (those not intrinsically resistant to Colistin) isolated from different sites were included in the study over a period of 1 years from September 2019 to August 2020. For all isolates identification and susceptibility was done by Vitek 2 Compact. BMD for Colistin susceptibility was done in our lab using MICROLATEST® marketed by Transasia in India. The breakpoints interpretation for Colistin was as per EUCAST 2019 criteria. A total of 59 CRE isolates were tested. The CRE isolates were Escherichia coli 71% (42/59) and Klebsiella pneumoniae 29% (17/59). Taking BMD as the reference method Essential agreement was 96.6% and Categorical agreement was 98.3% for Colistin susceptibility by Vitek 2 Compact. Very major error was seen in 1 case of Klebsiella pneumoniae (1.69%).Out of the 59 carbapenem resistant Gram negative isolates, 1 (1.69%) was found Colistin resistant taking BMD as the reference method. The BMD (broth micro-dilution) approach for establishing the Colistin MIC is reliable as well as is easily utilized but cost implication is there. The reliability of Vitek 2 Compact was high in our study when BMD was taken as the reference method, the sample size is too less to arrive at a conclusion, needs larger multicentric studies. The way forward would be studies correlating the Colistin MIC breakpoints and its relevance in clinical context.