Carbapenem-Resistant Gram-Negative Bacilli Characterization in a Tertiary Care Center from El Bajio, Mexico

Abstract

Carbapenem-resistant Gram-negative bacilli (CR-GNB) are a major public health concern. We aimed to evaluate the prevalence of CR-GNB and the frequency of carbapenemase-encoding genes in a tertiary referral center from El Bajio, Mexico. A cross-sectional study was conducted between January and October 2022; Gram-negative bacilli (GNB) were screened for in vitro resistance to at least one carbapenem. CR-GNB were further analyzed for carbapenemase-production through phenotypical methods and by real-time PCR for the following genes: blaKPC, blaGES, blaNDM, blaVIM, blaIMP, and blaOXA-48. In total, 37 out of 508 GNB were carbapenem-resistant (7.3%, 95% CI 5.2–9.9). Non-fermenters had higher rates of carbapenem resistance than Enterobacterales (32.5% vs. 2.6%; OR 18.3, 95% CI 8.5–39, p < 0.0001), and Enterobacter cloacae showed higher carbapenem resistance than other Enterobacterales (27% vs. 1.4%; OR 25.9, 95% CI 6.9–95, p < 0.0001). Only 15 (40.5%) CR-GNB had a carbapenemase-encoding gene; Enterobacterales were more likely to have a carbapenemase-encoding gene than non-fermenters (63.6% vs. 30.8%, p = 0.08); blaNDM-1 and blaNDM-5 were the main genes found in Enterobacterales; and blaIMP-75 was the most common for Pseudomonas aeruginosa. The mcr-2 gene was harbored in one polymyxin-resistant E. cloacae. In our setting, NDM was the most common carbapenemase; however, less than half of the CR-GNB showed a carbapenemase-encoding gene.

“Identification of potential high-risk clones of Carbapenem-ResistantPseudomonas aeruginosaco-producing, KPC-2, VIM-2 and OXA-74 from tertiary hospitals in Metro Manila, Philippines”

“…Resistance in CRPA isolates that do not produce carbapenemases could be mediated by a loss of porin D (OprD) and/or overexpression of efflux pumps (such as MexAB-OprM) (Amsalu et al, 2020; Arzanlou et al, 2017; Gashaw et al, 2024; Nieto-Saucedo et al, 2023). OprD is an outer membrane porin in P. aeruginosa that facilitates the uptake of basic amino acids and imipenem (Alcock et al, 2023).…”

Carbapenem Resistance in Animal-Environment-Food from Africa: A Systematic Review, Recommendations and Perspectives

“…13,14 Carbapenemase production is the main mechanism causing carbapenem-resistance. 15,16 Carbapenemases are molecules that break the beta-lactam ring, preventing the action of carbapenems. 16,17 Carbapenemases are encoded by genes located mostly on mobile genetic elements (MGE) such as plasmids, integrons, and transposons.…”