Molecular insights of β-lactams resistance in Klebsiella pneumoniae isolates with focus on multidrug resistance and virulence from colonization samples.

Klebsiella pneumoniae is associated with high resistance to antimicrobials and is common in isolates from colonization and healthcare-associated infections (HAIs). This study aims to develop assays to detect resistance genes belonging to the bla family and investigate metabolic pathways in resistant isolates of K. pneumoniae. The genes of the subfamilies included were: blaSHV, bla TEM, blaNDM, blaKPC, bla GES, bla CTX-M and relevant variants of the blaOXA subfamily. Mass spectrometry data were acquired on the Orbitrap IDX spectrometer (Thermo) connected to the Vanquish UPLC system. Isolates of K. pneumoniae (N = 122) were obtained from clinical samples from 04/23/2019 to 05/29/2021. A high prevalence of resistance to penicillins, cephalosporins and carbapenems was found among the isolates. The identified genotypic profile showed a high prevalence of genes belonging to Amblers classes of beta-lactamases A, B and D. In the metabolomic study, the N-fructosyl isoleucine metabolite was identified increased in multidrug-resistant (MDR) strains of K. pneumoniae compared to strains susceptible to antimicrobials. In conclusion, the assays developed were efficient in detecting the main genes of the bla family of resistance in K. pneumoniae. The use of the pentose phosphate metabolic pathway suggests a beneficial regulation of bacterial growth, and colonization in MDR K. pneumoniae strains, with may indicate the use of this pathway as a virulence mechanism in resistant strains.