Comparative Performance of Two Immunochromatographic Tests for the Rapid Detection of PCR Confirmed, Carbapenemase Producing-Enterobacterales

Abstract

The Gram-negative bacilli (GNB) tend to dominate the infectious pathology, often due to multidrug-resistant (MDR) strains and evolving with severe, complicated, and difficult-to-treat clinical forms. This study aimed to investigate by phenotypic and genotypic assays a representative set of carbapenem-resistant GNB strains to evaluate their contribution to appropriate epidemiological surveillance and therapy of associated infections. A number of 70 Enterobacterales MDR bacterial strains were consecutively isolated from patients with different infections (79 %) and carriers (rectal portages, 21 %) hospitalized at the Fundeni Clinical Institute from November 2017 - April 2018. The strains, previously characterized by PCR, were investigated comparatively by two immunochromatographic tests, NG-Test Carba 5 and RESIST-3 O.K.N., able to detect KPC, OXA-48 like NDM, VIM, IMP, and OXA-48 like, KPC, NDM, respectively. KPC was the main carbapenemase detected (37 %), followed by OXA-48 (30 %). Both rapid immunochromatographic tests demonstrated high sensitivity and specificity, the results being 100 % concordant with the results of the PCR method. The immunochromatographic assay is, therefore, a cheap and reliable method for the rapid detection, within 15 minutes, of carbapenemase-producing strains. Rapid and accurate identification of carbapenemases is significant for clinical and epidemiological purposes, infection control, and antimicrobial therapy's effectiveness.