Assessment of VITEK 2 system and MALDI-TOF MS for Identification of Lactose-Fermenting Bacteria: Comparing with Whole-Genome Sequencing - as a Gold Standard.

Authors: Bhavita Thakorbhai Prajapati, Anant Prabhakar Marathe, Asmabanu Mahammed Hanif Shaikh, shital sangani

DOI: 10.18231/j.ijmmtd.12048.1761395421

Keywords: MDR lactose fermenters, WGS, MALDI-TOF MS, VITEK 2 system, percentage of agreement

Abstract: Introduction: The Vitek 2 system is used widely for ID and AST of clinical bacterial isolates. MALDI-TOF-MS was once used to study accuracy and reproducibility. Recently, WGS has been instrumental in genomic sequencing as a gold standard for species identification. The AST data is based on species of individual bacterial species; erroneous ID can lead to wrong AST interpretation and faulty antibiotic prescriptions. Aim and objective: To study the percentage agreement in species identification of lactose fermenters isolated from clinical specimens by the Vitek 2 system and MALDI-TOF-MS with WGS as a gold standard. Material and Methods: A prospective study was conducted from May 2023 to December 2024 at a tertiary care hospital in Waghodia, Vadodara, Gujarat, India. This study included 117 clinical isolates collected from patients admitted to ICUs, specifically of Escherichia coli and Klebsiella pneumoniae. All isolates were identified by the Vitek 2 compact system, MALDI-ToF-MS, and whole-genome sequencing. Result: out of 69 K. pneumoniae, 67 were correctly identified by the Vitek 2 compact system and 54 by the MALDI TOF MS system. In E. coli, the MALDI TOF MS system identified 45 (45/48) and 42 (42/48) correctly identified by the Vitek 2 compact System. Conclusion: Identification of Clinical isolates to the species level is vital for the prediction of intrinsic resistance and antibiotic susceptibility as per CLSI guidelines. The VITEK 2 shows good concordance with WGS and can be used as a sole system for species identification of lactose fermenters like Klebsiella pneumoniae and E. coli.