Novel allelic variants of bla carried on IncN and IncC plasmids isolated from clinical cases in Argentina. In vivo emergence of bla.

Background: The OXA-48-like enzymes are members of the class D β-lactamases, primarily detected in Enterobacterales, with the capacity to hydrolyze carbapenems. The allelic variant bla, which has low hydrolytic activity towards carbapenemes, was detected in Argentina in 2011 and spread successfully since then, giving sporadic origin to novel local variants.

Aim: To study the phenotypic profile and the dissemination strategies of two novel OXA enzymes, bla and bla, harbored in Escherichia coli M17224 and Klebsiella pneumoniae M21014, isolated from two pediatric patients.

Crystal structure of the class A extended-spectrum β-lactamase CTX-M-96 in complex with relebactam at 1.03 Angstrom resolution.

The use of β-lactam/β-lactamase inhibitors constitutes an important strategy to counteract β-lactamases in multidrug-resistant (MDR) Gram-negative bacteria. Recent reports have described ceftazidime-/avibactam-resistant isolates producing CTX-M variants with different amino acid substitutions (e.g.

Spread and persistence of antimicrobial resistance genes in wastewater from human and animal sources in São Paulo, Brazil.

The spread of antimicrobial resistance (AMR) through multiple reservoirs is a global concern. Wastewater is a critical AMR dissemination source, so this study aimed to assess the persistence of resistance genetic markers in wastewater using a culture-independent approach. Raw and treated wastewater samples (n = 121) from a wastewater treatment plant (WWTP), a human hospital, a veterinary hospital, and a pig farm were monthly collected and concentrated by filtration.

Biochemical and Structural Characterization of CRH-1, a Carbapenemase from Chromobacterium haemolyticum Related to KPC β-Lactamases.

KPC-2 is one of the most relevant serine-carbapenemases among the carbapenem-resistant We previously isolated from the environmental species Chromobacterium haemolyticum a class A CRH-1 β-lactamase displaying 69% amino acid sequence identity with KPC-2. The objective of this study was to analyze the kinetic behavior and crystallographic structure of this β-lactamase. Our results showed that CRH-1 can hydrolyze penicillins, cephalosporins (except ceftazidime), and carbapenems with similar efficacy compared to KPC-2.

Boronic Acid Transition State Inhibitors as Potent Inactivators of KPC and CTX-M β-Lactamases: Biochemical and Structural Analyses.

Design of novel β-lactamase inhibitors (BLIs) is one of the currently accepted strategies to combat the threat of cephalosporin and carbapenem resistance in Gram-negative bacteria. oronic cid ransition tate nhibitors (BATSIs) are competitive, reversible BLIs that offer promise as novel therapeutic agents. In this study, the activities of two α-amido-β-triazolylethaneboronic acid transition state inhibitors (S02030 and MB_076) targeting representative KPC (KPC-2) and CTX-M (CTX-M-96, a CTX-M-15-type extended-spectrum β-lactamase [ESBL]) β-lactamases were evaluated.