Comparative Evaluation of Two Automated ID/AST Systems and Mikrolatest Kit in Assessing the Colistin Susceptibility of Carbapenem-Resistant Enterobacteriaceae Isolates: A Single-Center Exploratory Study from North India.

AIMS

To generate preliminary data about comparative evaluation of two automated ID/AST systems and Mikrolatest kit in determining colistin susceptibility of carbapenem-resistant spp.

MATERIALS AND METHODS

Twenty-three carbapenem-resistant and and two carbapenem-sensitive multidrug-resistant isolates obtained from various clinical samples of inpatients were included in the study. Species-level identification and antibiotic susceptibility testing (AST) of test isolates was performed using BD phoenix and MicroScan WalkAway 96 Plus automated systems. Identity was reconfirmed by matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS). Additional colistin susceptibility testing was performed using Mikrolatest MIC colistin susceptibility testing kit (reference method).

RESULTS

Results showed that 16% isolates (27.3% [3/11] and 7.1% [1/14] ) exhibited colistin resistance by the reference method. While the categorical agreement between BD Phoenix M50 ID/AST system and reference test w. r. t colistin susceptibility results was 100% and 92.9% for & , respectively, it was much lower between MicroScan WalkAway 96 plus ID/AST system and the latter. Almost perfect agreement (96%; kappa: 0.834) was observed between BD Phoenix M50 system and reference method.

CONCLUSIONS

The results of this study are preliminary and cannot be generalized. Multicentric studies with large sample sizes should be conducted throughout the country to gain a deeper understanding of the subject under consideration.