Durlobactam in combination with β-lactams to combat .

() presents significant clinical challenges. This study evaluated the synergistic effects of a β-lactam and β-lactamase inhibitor combination against and explored the underlying mechanisms. Synergy was assessed through MIC tests and time-kill studies, and binding affinities of nine β-lactams and BLIs to eight target receptors (L,D-transpeptidases [LDT] 1-5, D,D-carboxypeptidase, penicillin-binding protein [PBP] B, and PBP-lipo) were assessed using mass spectrometry and kinetic studies.

Synergistic effects of sulopenem in combination with cefuroxime or durlobactam against .

Unlabelled: () affects patients with immunosuppression or underlying structural lung diseases such as cystic fibrosis (CF). Additionally, poses clinical challenges due to its resistance to multiple antibiotics. Herein, we investigated the synergistic effect of dual β-lactams [sulopenem and cefuroxime (CXM)] or the combination of sulopenem and CXM with β-lactamase inhibitors [BLIs-avibactam (AVI) or durlobactam (DUR)].

Structural and Dynamic Features of Acinetobacter baumannii OXA-66 β-Lactamase Explain Its Stability and Evolution of Novel Variants.

OXA-66 is a member of the OXA-51 subfamily of class D β-lactamases native to the Acinetobacter genus that includes Acinetobacter baumannii, one of the ESKAPE pathogens and a major cause of drug-resistant nosocomial infections. Although both wild type OXA-66 and OXA-51 have low catalytic activity, they are ubiquitous in the Acinetobacter genomes. OXA-51 is also remarkably thermostable.

Durlobactam, a Diazabicyclooctane β-Lactamase Inhibitor, Inhibits BlaC and Peptidoglycan Transpeptidases of .

Peptidoglycan synthesis is an underutilized drug target in (). Diazabicyclooctanes (DBOs) are a class of broad-spectrum β-lactamase inhibitors that also inhibit certain peptidoglycan transpeptidases that are important in mycobacterial cell wall synthesis. We evaluated the DBO durlobactam as an inhibitor of BlaC, the β-lactamase, and multiple peptidoglycan transpeptidases (PonA1, Ldt, Ldt, Ldt, and Ldt).

Natural protein engineering in the Ω-loop: the role of Y221 in ceftazidime and ceftolozane resistance in -derived cephalosporinase.

A wide variety of clinically observed single amino acid substitutions in the Ω-loop region have been associated with increased minimum inhibitory concentrations and resistance to ceftazidime (CAZ) and ceftolozane (TOL) in -derived cephalosporinase and other class C β-lactamases. Herein, we demonstrate the naturally occurring tyrosine to histidine substitution of amino acid 221 (Y221H) in -derived cephalosporinase (PDC) enables CAZ and TOL hydrolysis, leading to similar kinetic profiles ( = 2.3 ± 0.

Synthesis of a Novel Boronic Acid Transition State Inhibitor, MB076: A Heterocyclic Triazole Effectively Inhibits -Derived Cephalosporinase Variants with an Expanded-Substrate Spectrum.

Class C -derived cephalosporinases (ADCs) represent an important target for inhibition in the multidrug-resistant pathogen . Many ADC variants have emerged, and characterization of their structural and functional differences is essential. Equally as important is the development of compounds that inhibit all prevalent ADCs despite these differences.

The Effectiveness of Imipenem-Relebactam against Ceftazidime-Avibactam Resistant Variants of the KPC-2 β-Lactamase.

Background: Ceftazidime-avibactam was approved by the FDA to treat infections caused by Enterobacterales carrying . However, variants of KPC-2 with amino acid substitutions at position 179 have emerged and confer resistance to ceftazidime-avibactam.

Methods: The activity of imipenem-relebactam was assessed against a panel of 19 KPC-2 D179 variants.

Sulfonamidoboronic Acids as "Cross-Class" Inhibitors of an Expanded-Spectrum Class C Cephalosporinase, ADC-33, and a Class D Carbapenemase, OXA-24/40: Strategic Compound Design to Combat Resistance in .

is a Gram-negative organism listed as an urgent threat pathogen by the World Health Organization (WHO). Carbapenem-resistant (CRAB), especially, present therapeutic challenges due to complex mechanisms of resistance to -lactams. One of the most important mechanisms is the production of -lactamase enzymes capable of hydrolyzing -lactam antibiotics.

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.

Imipenem/Relebactam Resistance in Clinical Isolates of Extensively Drug Resistant Pseudomonas aeruginosa: Inhibitor-Resistant β-Lactamases and Their Increasing Importance.

Multidrug-resistant (MDR) Pseudomonas aeruginosa infections are a major clinical challenge. Many isolates are carbapenem resistant, which severely limits treatment options; thus, novel therapeutic combinations, such as imipenem-relebactam (IMI/REL), ceftazidime-avibactam (CAZ/AVI), ceftolozane-tazobactam (TOL/TAZO), and meropenem-vaborbactam (MEM/VAB) were developed. Here, we studied two extensively drug-resistant (XDR) P.

Different Conformations Revealed by NMR Underlie Resistance to Ceftazidime/Avibactam and Susceptibility to Meropenem and Imipenem among D179Y Variants of KPC β-Lactamase.

β-Lactamase-mediated resistance to ceftazidime-avibactam (CZA) is a serious limitation in the treatment of Gram-negative bacteria harboring Klebsiella pneumoniae carbapenemase (KPC). Herein, the basis of susceptibility to carbapenems and resistance to ceftazidime (CAZ) and CZA of the D179Y variant of KPC-2 and -3 was explored. First, we determined that resistance to CZA in a laboratory strain of Escherichia coli DH10B was not due to increased expression levels of the variant enzymes, as demonstrated by reverse transcription PCR (RT-PCR).

Inhibiting Mycobacterium abscessus Cell Wall Synthesis: Using a Novel Diazabicyclooctane β-Lactamase Inhibitor To Augment β-Lactam Action.

Mycobacterium abscessus () infections are a growing menace to the health of many patients, especially those suffering from structural lung disease and cystic fibrosis. With multidrug resistance a common feature and a growing understanding of peptidoglycan synthesis in , it is advantageous to identify potent β-lactam and β-lactamase inhibitor combinations that can effectively disrupt cell wall synthesis. To improve existing therapeutic regimens to address serious infections, we evaluated the ability of durlobactam (DUR), a novel diazobicyclooctane β-lactamase inhibitor to restore susceptibilities in combination with β-lactams and provide a biochemical rationale for the activity of this compound.

Insights Into the Inhibition of MOX-1 β-Lactamase by S02030, a Boronic Acid Transition State Inhibitor.

The rise of multidrug resistant (MDR) Gram-negative bacteria has accelerated the development of novel inhibitors of class A and C β-lactamases. Presently, the search for novel compounds with new mechanisms of action is a clinical and scientific priority. To this end, we determined the 2.

A comprehensive and contemporary "snapshot" of β-lactamases in carbapenem resistant Acinetobacter baumannii.

Successful treatment of Acinetobacter baumannii infections require early and appropriate antimicrobial therapy. One of the first steps in this process is understanding which β-lactamase (bla) alleles are present and in what combinations. Thus, we performed WGS on 98 carbapenem-resistant A.

Resistance to Novel β-Lactam-β-Lactamase Inhibitor Combinations: The "Price of Progress".

Significant advances were made in antibiotic development during the past 5 years. Novel agents were added to the arsenal that target critical priority pathogens, including multidrug-resistant Pseudomonas aeruginosa and carbapenem-resistant Enterobacterales. Of these, 4 novel β-lactam-β-lactamase inhibitor combinations (ceftolozane-tazobactam, ceftazidime-avibactam, meropenem-vaborbactam, and imipenem-cilastatin-relebactam) reached clinical approval in the United States.

Structural Insights into Inhibition of the Acinetobacter-Derived Cephalosporinase ADC-7 by Ceftazidime and Its Boronic Acid Transition State Analog.

Extended-spectrum class C β-lactamases have evolved to rapidly inactivate expanded-spectrum cephalosporins, a class of antibiotics designed to be resistant to hydrolysis by β-lactamase enzymes. To better understand the mechanism by which -erived ephalosporinase-7 (ADC-7), a chromosomal AmpC enzyme, hydrolyzes these molecules, we determined the X-ray crystal structure of ADC-7 in an acyl-enzyme complex with the cephalosporin ceftazidime (2.40 Å) as well as in complex with a boronic acid transition state analog inhibitor that contains the R1 side chain of ceftazidime (1.

Predicting β-lactam resistance using whole genome sequencing in Klebsiella pneumoniae: the challenge of β-lactamase inhibitors.

Although multiple antimicrobial resistance (AMR) determinants can confer the same in vitro antimicrobial susceptibility testing (AST) phenotype, their differing effect on optimal therapeutic choices is uncertain. Using a large population-based collection of clinical strains spanning a 3.5-year period, we applied WGS to detect inhibitor resistant (IR), extended-spectrum β-lactamase (ESBL), and carbapenem resistant (CR) β-lactamase (bla) genes and compared the genotype to the AST phenotype in select isolates.

1,2,3-Triazolylmethaneboronate: A Structure Activity Relationship Study of a Class of β-Lactamase Inhibitors against Cephalosporinase.

Boronic acid transition state inhibitors (BATSIs) are known reversible covalent inhibitors of serine β-lactamases. The selectivity and high potency of specific BATSIs bearing an amide side chain mimicking the β-lactam's amide side chain are an established and recognized synthetic strategy. Herein, we describe a new class of BATSIs where the amide group is replaced by a bioisostere triazole; these compounds were designed as molecular probes.

α-Triazolylboronic Acids: A Promising Scaffold for Effective Inhibitors of KPCs.

Boronic acids are known reversible covalent inhibitors of serine β-lactamases. The selectivity and high potency of specific boronates bearing an amide side chain that mimics the β-lactam's amide side chain have been advanced in several studies. Herein, we describe a new class of boronic acids in which the amide group is replaced by a bioisostere triazole.

Insights into the l,d-Transpeptidases and d,d-Carboxypeptidase of Mycobacterium abscessus: Ceftaroline, Imipenem, and Novel Diazabicyclooctane Inhibitors.

is a highly drug-resistant nontuberculous mycobacterium (NTM). Efforts to discover new treatments for infections are accelerating, with a focus on cell wall synthesis proteins ( l,d-transpeptidases 1 to 5 [Ldt to Ldt] and d,d-carboxypeptidase) that are targeted by β-lactam antibiotics. A challenge to this approach is the presence of chromosomally encoded β-lactamase (Bla).

Structures of FOX-4 Cephamycinase in Complex with Transition-State Analog Inhibitors.

Boronic acid transition-state analog inhibitors (BATSIs) are partners with β-lactam antibiotics for the treatment of complex bacterial infections. Herein, microbiological, biochemical, and structural findings on four BATSIs with the FOX-4 cephamycinase, a class C β-lactamase that rapidly hydrolyzes cefoxitin, are revealed. FOX-4 is an extended-spectrum class C cephalosporinase that demonstrates conformational flexibility when complexed with certain ligands.

A Standard Numbering Scheme for Class C β-Lactamases.

Unlike for classes A and B, a standardized amino acid numbering scheme has not been proposed for the class C (AmpC) β-lactamases, which complicates communication in the field. Here, we propose a scheme developed through a collaborative approach that considers both sequence and structure, preserves traditional numbering of catalytically important residues (Ser, Lys, Tyr, and Lys), is adaptable to new variants or enzymes yet to be discovered and includes a variation for genetic and epidemiological applications.

Nacubactam Enhances Meropenem Activity against Carbapenem-Resistant Klebsiella pneumoniae Producing KPC.

Carbapenem-resistant (CRE) are resistant to most antibiotics, making CRE infections extremely difficult to treat with available agents. carbapenemases (KPC-2 and KPC-3) are predominant carbapenemases in CRE in the United States. Nacubactam is a bridged diazabicyclooctane (DBO) β-lactamase inhibitor that inactivates class A and C β-lactamases and exhibits intrinsic antibiotic and β-lactam "enhancer" activity against In this study, we examined a collection of meropenem-resistant isolates carrying or ; meropenem-nacubactam restored susceptibility.

Resurrecting Old β-Lactams: Potent Inhibitory Activity of Temocillin against Multidrug-Resistant Species Isolates from the United States.

spp. are opportunistic human pathogens that infect persons with cystic fibrosis and the immunocompromised. spp.