Comparison of Commercial Lateral Flow Immunochromatography with Phenotypic and Genotypic Assays for the Detection of Carbapenemase-Producing Gram-Negative Bacteria at Tanta University Hospitals

TL;DR

This study compares a fast lateral flow test with traditional methods for detecting antibiotic-resistant bacteria in hospital settings.

Contribution

The study evaluates the accuracy of lateral flow immunoassays as a rapid alternative to phenotypic and genotypic methods for detecting carbapenemase-producing bacteria.

Findings

Lateral flow immunoassays showed high sensitivity and specificity for detecting specific carbapenemase genes.

The LFIA had an overall accuracy of 92-94% when compared to molecular assays.

blaNDM was the most frequently detected gene, while blaIMP was the least.

Abstract

It is crucial to identify Enterobacterales that produce carbapenemase to treat and manage hospital infections. The suggested techniques for their identification need a lengthy wait, technical knowledge, and training. Lateral flow immunoassays (LFIAs) provide a solution to these requirements. Thus, this study compared LFIA with phenotypic and genotypic tests for carbapenemase-producing bacteria. Fifty clinical isolates of carbapenem-resistant superbugs were examined. KPC, VIM, NDM, IMP, and OXA-48-like enzymes were evaluated and compared with phenotypic tests and LFIA. Regarding the phenotypic characteristics, the mCIM was positive in 37/50 (74%), and the eCIM was positive in 21/50 (42%). Regarding using LFIA, 41 out of the total isolates (82%) gave a positive red line with one or more of the tested genes. The most frequently detected gene was blaNDM (27/50 (54%)), and the least detected one was blaIMP (14/50 (28%)), which was in accordance with the PCR results. While investigating the accuracy of LFIA vs. PCR, it was found that LFIA had 100% sensitivity in the detection of the blaNDM and blaOXA genes, with 85.2% and 91.4% specificity, respectively, while for the blaIMP, blaKPC, and blaVIM genes, the values were 91.7% and 92.1%, 94.1% and 90.9%, and 95.5% and 89.3%, respectively. The overall accuracy of LFIA ranged from 92 to 94%. Our comparison with molecular assays revealed remarkable agreement, so we propose that this test might be utilized as a supplementary tool.

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