RESUMEN
The diazabicyclooctanes (DBOs) are a class of serine ß-lactamase (SBL) inhibitors that use a strained urea moiety as the warhead to react with the active serine residue in the active site of SBLs. The first in-class drug, avibactam, as well as several other recently approved DBOs (e.g., relebactam) or those in clinical development (e.g., nacubactam and zidebactam) potentiate activity of ß-lactam antibiotics, to various extents, against carbapenem-resistant Enterobacterales (CRE) carrying class A, C, and D SBLs; however, none of these are able to rescue the activity of ß-lactam antibiotics against carbapenem-resistant Acinetobacter baumannii (CRAB), a WHO "critical priority pathogen" producing class D OXA-type SBLs. Herein, we describe the chemical optimization and resulting structure-activity relationship, leading to the discovery of a novel DBO, ANT3310, which uniquely has a fluorine atom replacing the carboxamide and stands apart from the current DBOs in restoring carbapenem activity against OXA-CRAB as well as SBL-carrying CRE pathogens.
Asunto(s)
Acinetobacter/efectos de los fármacos , Antibacterianos/farmacología , Enterobacteriaceae/efectos de los fármacos , Octanos/química , beta-Lactamasas/química , Animales , Antibacterianos/química , Antibacterianos/metabolismo , Sitios de Unión , Carbapenémicos/farmacología , Evaluación Preclínica de Medicamentos , Farmacorresistencia Bacteriana/efectos de los fármacos , Semivida , Ratones , Pruebas de Sensibilidad Microbiana , Simulación del Acoplamiento Molecular , Octanos/metabolismo , Octanos/farmacología , Estereoisomerismo , Relación Estructura-Actividad , Inhibidores de beta-Lactamasas/química , Inhibidores de beta-Lactamasas/metabolismo , Inhibidores de beta-Lactamasas/farmacología , beta-Lactamasas/metabolismoRESUMEN
The clinical effectiveness of carbapenem antibiotics such as meropenem is becoming increasingly compromised by the spread of both metallo-ß-lactamase (MBL) and serine-ß-lactamase (SBL) enzymes on mobile genetic elements, stimulating research to find new ß-lactamase inhibitors to be used in conjunction with carbapenems and other ß-lactam antibiotics. Herein, we describe our initial exploration of a novel chemical series of metallo-ß-lactamase inhibitors, from concept to efficacy, in a survival model using an advanced tool compound (ANT431) in conjunction with meropenem.
Asunto(s)
Antibacterianos/farmacología , Enterobacteriaceae Resistentes a los Carbapenémicos/efectos de los fármacos , Farmacorresistencia Bacteriana Múltiple , Infecciones por Enterobacteriaceae/tratamiento farmacológico , Inhibidores de beta-Lactamasas/química , Carbapenémicos/farmacología , Cristalografía por Rayos X , Concentración 50 Inhibidora , Meropenem/farmacología , Pruebas de Sensibilidad Microbiana , Ácidos Picolínicos/química , Ácidos Picolínicos/farmacología , Unión Proteica , Relación Estructura-Actividad , Inhibidores de beta-Lactamasas/farmacología , beta-LactamasasRESUMEN
Since the ban gene of bacteriophage P1 suppresses a number of conditionally lethal dnaB mutations in Escherichia coli, it was assumed that Ban protein is a DNA helicase (DnaB analogue) that can substitute for DnaB in the host replication machinery. We isolated and sequenced the ban gene, purified the product, and analysed the function of Ban protein in vitro and in vivo. Ban hydrolyses ATP, unwinds DNA and forms hexamers in the presence of ATP and magnesium ions. Since all existing conditionally lethal dnaB strains bear DnaB proteins that may interfere with the protein under study, we constructed a dnaB null strain by using a genetic set-up designed to provoke the conditional loss of the entire dnaB gene from E.coli cells. This novel tool was used to show that Ban restores the viability of cells that completely lack DnaB at 30 degrees C, but not at 42 degrees C. Surprisingly, growth was restored by the dnaB252 mutation at a temperature that is restrictive for ban and dnaB252 taken separately. This indicates that Ban and DnaB are able to interact in vivo. Complementary to these results, we demonstrate the formation of DnaB-Ban hetero-oligomers in vitro by ion exchange chromatography. We discuss the interaction of bacterial proteins and their phage-encoded analogues to fulfil functions that are essential to phage and host growth.