Evaluation of a new rapid immunochromatographic assay for the detection of GES-producing Gram-negative bacteria

Background As carbapenemase-producing Enterobacterales are increasingly reported worldwide, their rapid detection is crucial to reduce their spread and prevent infections and outbreaks. Lateral flow immunoassays (LFIAs) have become major tools for the detection of carbapenemases. However, as for most commercially available assays, only the five main carbapenemases are targeted. Objectives Here, we have developed and evaluated an LFIA prototype for the rapid and reliable detection of the increasingly identified GES-type beta-lactamases. Methods The GES LFIA was validated on 103 well-characterized Gram-negative isolates expressing various beta-lactamases grown on Mueller-Hinton (MH) agar, chromogenic, and chromogenic/selective media. Results The limit of detection of the assay was 10(6) cfu per test with bacteria grown on MH agar plates. GES LFIA accurately detected GES-type beta-lactamases irrespective of the culture media and the bacterial host. The GES LFIA was not able to distinguish between GES-ESBLs and GES-carbapenemases. Because GES enzymes are still rare, their detection as an ESBL or a carbapenemase remains important, especially because extensive use of carbapenems to treat ESBL infections may select for GES variants capable of hydrolysing carbapenems. Conclusions The GES LFIA is efficient, rapid and easy to implement in the routine workflow of a clinical microbiology laboratory for the confirmation of GES-type beta-lactamases. Combining it with immunochromatographic assays targeting the five main carbapenemases (KPC, NDM, VIM, IMP and OXA-48) would improve the overall sensitivity for the most frequently encountered carbapenemases and ESBLs, especially in non-fermenters.

Automated summary

A LFIA prototype has been developed and evaluated for the rapid and reliable detection of GES-type beta-lactamases. The method is efficient, rapid, and easy to implement, making it suitable for confirmation of GES-type beta-lactamases in clinical microbiology laboratories.