Comparison of Lateral Flow Immunochromatography and Phenotypic Assays to PCR for the Detection of Carbapenemase-Producing Gram-Negative Bacteria, a Multicenter Experience in Mexico

Abstract

The identification of carbapenemase-producing Enterobacterales and <i>Pseudomonas aeruginosa</i> is important for treating and controlling hospital infections. The recommended methods for their identification require a long waiting time, technical training, and expertise. Lateral flow immunoassays such as NG-Test CARBA 5^® overcome these needs. We analyzed 84 clinical isolates of carbapenem-resistant Enterobacterales and <i>P. aeruginosa</i> from four different hospitals in a two-year period. Antimicrobial resistance patterns were confirmed with the broth dilution method. Evaluation of KPC, VIM, NDM, IMP, and OXA-48-like enzymes was performed and compared to NG-Test CARBA 5 and phenotypic assays. Enterobacterales represented 69% of isolates and <i>P. aeruginosa</i> represented 31%. Carbapenemase-producing strains were 51 (88%) of Enterobacterales and 23 (88.4%) of <i>P. aeruginosa</i>; 20 (34%) and 23 (88%) were Class B ß-lactamases, respectively. The NG-Test CARBA 5^® assay for Enterobacterales showed high sensitivity (98%), specificity (100%), and PPV (100%); however, it did not for <i>P. aeruginosa</i>. The Kappa concordance coefficient was 0.92 for Enterobacterales and 0.52 for <i>P. aeruginosa</i>. NG-Test CARBA 5^® is a fast and easy-to-use assay. In Enterobacterales, we found excellent agreement in our comparison with molecular tests. Despite the low agreement in <i>P. aeruginosa</i>, we suggest that this test could be used as a complementary tool.