NB2001, a Novel Antibacterial Agent with Broad-Spectrum Activity and Enhanced Potency against β-Lactamase-Producing Strains

Abstract

Enzyme-catalyzed therapeutic activation (ECTA) is a novel prodrug strategy to overcome drug resistance resulting from enzyme overexpression. ␤-Lactamase overexpression is a common mechanism of bacterial resistance to ␤-lactam antibiotics. We present here the results for one of the ␤-lactamase ECTA compounds, NB2001, which consists of the antibacterial agent triclosan in a prodrug form with a cephalosporin scaffold. Unlike conventional ␤-lactam antibiotics, where hydrolysis of the ␤-lactam ring inactivates the antibiotic, hydrolysis of NB2001 by ␤-lactamase releases triclosan. Evidence supporting the proposed mechanism is as follows. (i) NB2001 is a substrate for TEM-1 ␤-lactamase, forming triclosan with a second-order rate constant (k cat /K m ) of greater than 77,000 M ؊1 s ؊1 .(ii) Triclosan is detected in NB2001-treated, ␤-lactamase-producing Escherichia coli but not in E. coli that does not express ␤-lactamase. (iii) NB2001 activity against ␤-lactamaseproducing E. coli is decreased in the presence of the ␤-lactamase inhibitor clavulanic acid. NB2001 was similar to or more potent than reference antibiotics against clinical isolates of Staphylococcus aureus (including MRSA), Staphylococcus epidermidis, Streptococcus pneumoniae, vancomycin-resistant Enterococcus faecalis, Moraxella catarrhalis and Haemophilus influenzae. NB2001 is also active against Klebsiella pneumoniae, Enterobacter aerogenes, and Enterobacter cloacae. The results indicate that NB2001 is a potent, broad-spectrum antibacterial agent and demonstrate the potential of ECTA in overcoming ␤-lactamase-mediated resistance.

Mechanism of Action of NB2001 and NB2030, Novel Antibacterial Agents Activated by β-Lactamases

“…␤-Lactamase inhibitors, such as clavulanic acid and the penicillanic acid sulfones, mostly target class A enzymes; and their use in combination with older compounds has restored the broad-spectrum activities of older compounds, such as amoxicillin (18,22,25,26). Inhibitors that target class C and class B ␤-lactamases have yet to reach clinical development.Exploiting common ␤-lactamases to generate novel antibacterials is a strategy originally used by O'Callaghan et al (24) and subsequently by Mobashery and Johnston (20) and other investigators (6,10,16). It has been part of NewBiotics' general enzyme-catalyzed therapeutic activation (ECTA) prodrug approach that harnesses unique enzymes in bacteria to achieve selective release of cytotoxic agents from substrate-like molecules (16; M. V.…”

“…Exploiting common ␤-lactamases to generate novel antibacterials is a strategy originally used by O'Callaghan et al (24) and subsequently by Mobashery and Johnston (20) and other investigators (6,10,16). It has been part of NewBiotics' general enzyme-catalyzed therapeutic activation (ECTA) prodrug approach that harnesses unique enzymes in bacteria to achieve selective release of cytotoxic agents from substrate-like molecules (16; M. V. Sergeeva, G. H. Khambatta, B. E. Cathers, R. S. Castillo, V. R. Doppalapudi, H. H. Bendall, A. R. Bueno, J. Y. Lee, Q. Li, and N. H. Georgopapadakou, Abstr.…”

“…(13,17,31) was provided by K. Bush, and S. aureus strains RN4220 and PC1 (14,30,32) were provided by J. Iandolo. E. coli (TEM-1) and its parent strain, E. coli N, have been described previously (16).…”

First report on rapid screening of nanomaterial-based antimicrobial agents against β-lactamase resistance using pGLO plasmid transformed Escherichia coli HB 101 K-12

“…In this study, transformed E. coli exhibited enhanced susceptibility to aloin than non-transformed E. coli. The increased susceptibility could be explained by 'negative cross-resistance' or 'collateral sensitivity', where the induction of resistance to one compound enhances the toxicity to other compounds (Li et al 2002;Palmer et al 2010). Previously, similar phenomenon was observed through the increased susceptibility of E. coli to fusaric acid consequent to development of resistance against tetracyclines by modification of efflux pumps (Bochner et al 1980).…”

Actividad inhibitoria de dihidroxifenilpropenona sobre β-lactamasa de Enterobacter cloacae: estudio preliminar en el desarrollo de fármacos para enfrentar la resistencia bacteriana

“…A pesar de que los compuestos inhibidores de enzimas, como el ácido clavulánico y las sulfonas del ácido penicilánico (sulbactam y tazobactam), han ayudado a controlar la resistencia, se ha visto que su actividad es relativamente limitada contra las betalactamasas de clase C y contra algunas enzimas de clase A y, además, se ha reportado que estos compuestos, al presentar el mismo núcleo químico de los fármacos betalactámicos, pueden inducir la expresión de betalactamasas en microorganismos resistentes (16)(17)(18)(19)(20)(21)(22).…”