Concordance of Enterococcus species identification by two different identification systems VITEK2 and MALDI-TOF, compared with WGS (gold standard).

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

DOI: 10.18231/j.ijmmtd.12016.1760520062

Keywords: Bloodstream infections,Enterococcus,MALDI-TOF,VITEK2,Whole Genome Sequencing

Abstract: Abstract: Aims & Objective: This study aims to compare the performance of two commercial systems, VITEK2 and MALDI-TOF (Matrix-assisted laser desorption-ionization time-of-flight mass spectrometry), in identifying Enterococcus species when compared against Whole Genome Sequencing, which is considered the gold standard. Introduction: Bacterial species identification is vital for taking decision of antimicrobial therapy. Bacteria can be quickly identified through a system database, which is particularly significant for critically ill patients. This becomes particularly important in cases where antimicrobial susceptibility varies significantly between Enterococcus faecium and Enterococcus faecalis. According to the literature, Enterococcus faecium is intrinsically resistant to ampicillin and frequently exhibits a high rate of vancomycin resistance, which is quite rare in Enterococcus faecalis. Materials and Methods: 44 Enterococcus spp. were identified by a biochemical-based system, VITEK2 and a proteomics-based system, MALDI-TOF. All the isolates were subjected to Whole Genome Sequencing for species identification, using the Illumina NovaSeq instrument. Results: Among 44 Enterococcus spp., 31 were identified as Enterococcus faecium and 13 were identified as Enterococcus faecalis by VITEK2. All Enterococcus were showing concordance report when it comes to identification at the Genus level, by both systems. And at the species level 84% of Enterococcus faecium were showing concordance with MALDI-TOF. And 92.3% Enterococcus faecalis by VITEK2 were showing concordance with MALDI-TOF. Conclusion: Quick and precise identification methods in the laboratory are required to enable the identification of bacterial species. In the current study, we associated the relative precision of VITEK2 and MALDI-TOF, using Enterococci isolates from clinical specimens, and compared the results, considering WGS as a gold standard method. Our results evidently exhibited that VITEK2 is a dependable tool for identifying Enterococcus spp. with superior inequivalent power with acceptable discrepancies.