A5091210745- Antibiotic Resistance in Bacteria
- Bacterial Genetics and Biotechnology
- Tuberculosis Research and Epidemiology
- Pneumocystis jirovecii pneumonia detection and treatment
- Pneumonia and Respiratory Infections
- Peptidase Inhibition and Analysis
- Enzyme Structure and Function
- Antimicrobial Resistance in Staphylococcus
- RNA and protein synthesis mechanisms
- Mycobacterium research and diagnosis
- Protein Structure and Dynamics
- Biochemical and Molecular Research
- Advanced Proteomics Techniques and Applications
- Antibiotics Pharmacokinetics and Efficacy
- Glycosylation and Glycoproteins Research
- Carbohydrate Chemistry and Synthesis
- Clostridium difficile and Clostridium perfringens research
- Analytical Chemistry and Chromatography
- Bacteriophages and microbial interactions
- Cancer, Lipids, and Metabolism
- Biopolymer Synthesis and Applications
- Chemical Synthesis and Analysis
- Synthesis of β-Lactam Compounds
- Amino Acid Enzymes and Metabolism
- Bacterial Identification and Susceptibility Testing
Centre de Recherche des Cordeliers
2015-2024
Université Paris Cité
2014-2024
Sorbonne Université
2014-2024
Inserm
2014-2024
Délégation Paris 5
2009-2019
Sorbonne Paris Cité
2011-2019
Délégation Paris 7
2017
Institut Parisien de Chimie Moléculaire
2013
Rhode Island Hospital
2013
Brown University
2013
beta-lactam antibiotics are ineffective against Mycobacterium tuberculosis, being rapidly hydrolyzed by the chromosomally encoded blaC gene product. The carbapenem class of beta-lactams very poor substrates for BlaC, allowing us to determine three-dimensional structure covalent BlaC-meropenem complex at 1.8 angstrom resolution. When meropenem was combined with beta-lactamase inhibitor clavulanate, potent activity laboratory strains M. tuberculosis observed [minimum inhibitory concentration...
The beta-lactam antibiotics remain the most commonly used to treat severe infections. Because of structural similarity between ring and d-alanyl(4)-d-alanine(5) extremity bacterial cell wall precursors, drugs act as suicide substrates dd-transpeptidases that catalyze last cross-linking step assembly. Here, we show this mechanism action can be defeated by a novel type transpeptidase identified for first time reverse genetics in abeta-lactam-resistant mutant Enterococcus faecium. enzyme,...
Members of the β-lactam class antibiotics, which inhibit bacterial d,d-transpeptidases involved in cell wall biosynthesis, have never been used systematically treatment Mycobacterium tuberculosis infections because this organism's resistance to β-lactams. The critical factor is constitutive production a chromosomally encoded, Ambler A β-lactamase, BlaC M. tuberculosis. We show that an extended spectrum β-lactamase (ESBL) with high levels penicillinase and cephalosporinase activity as well...
Abstract Objectives Two β-lactams, cefoxitin and imipenem, are part of the reference treatment for pulmonary infections with Mycobacterium abscessus. M. abscessus has recently been shown to produce a broad-spectrum β-lactamase, BlaMab, indicating that combination β-lactams BlaMab inhibitor may improve efficacy. The objectives this study were evaluate impact production on efficacy in vitro assess benefit inhibition activity intracellularly an animal model. Methods We analysed mechanism...
The target of β-lactam antibiotics is the D,D-transpeptidase activity penicillin-binding proteins (PBPs) for synthesis 4→3 cross-links in peptidoglycan bacterial cell walls. Unusual 3→3 formed by L,D-transpeptidases were first detected Escherichia coli more than four decades ago, however no phenotype has previously been associated with their synthesis. Here we show that production L,D-transpeptidase YcbB combination elevated (p)ppGpp alarmone RelA lead to full bypass PBPs and broad-spectrum...
The structure of Mycobacterium tuberculosis peptidoglycan is atypical since it contains a majority 3→3 cross-links synthesized by l,d-transpeptidases that replace 4→3 formed the d,d-transpeptidase activity classical penicillin-binding proteins. Carbapenems inactivate these l,d-transpeptidases, and meropenem combined with clavulanic acid bactericidal against extensively drug-resistant M. tuberculosis. Here, we used mass spectrometry stopped-flow fluorimetry to investigate kinetics mechanisms...
ABSTRACT The Mycobacterium tuberculosis peptidoglycan is cross-linked mainly by l , d -transpeptidases (LDTs), which are efficiently inactivated a single β-lactam class, the carbapenems. Development of carbapenems for treatment has recently raised considerable interest since these drugs, in association with β-lactamase inhibitor clavulanic acid, uniformly active against extensively drug-resistant M. and kill both exponentially growing dormant forms bacilli. We have purified five...
Imipenem and cefoxitin are used to treat Mycobacterium abscessus infections have moderate activity against this fast-growing mycobacterium (MIC50 of 16 32 mg/L, respectively). M. is highly resistant most other β-lactams, although the underlying mechanisms not been explored. Here, we characterized class A β-lactamase (BlaMab) investigated its role in β-lactam resistance. Hydrolysis kinetic parameters purified BlaMab were determined by spectrophotometry for various β-lactams compared with...
ABSTRACT Recent clinical studies indicate that meropenem, a β-lactam antibiotic, is promising candidate for therapy of drug-resistant tuberculosis. However, meropenem chemically unstable, requires frequent intravenous injection, and must be combined with β-lactamase inhibitor (clavulanate) optimal activity. Here, we report faropenem, stable orally bioavailable β-lactam, efficiently kills Mycobacterium tuberculosis even in the absence clavulanate. The target enzymes, l , d -transpeptidases,...
The β-lactam antibiotics mimic the d-alanyl<sup>4</sup>-d-alanine<sup>5</sup> extremity of peptidoglycan precursors and act as "suicide" substrates dd-transpeptidases that catalyze last cross-linking step synthesis. We have previously shown bypass by ld-transpeptidase <i>Enterococcus faecium</i> (Ldt<sub>fm</sub>) leads to high level resistance ampicillin. Ldt<sub>fm</sub> is specific for l-lysyl<sup>3</sup>-d-alanine<sup>4</sup> bond containing a tetrapeptide stem lacking...
Significance The antimicrobial effect of copper has been known since ancient times and it is well that alloy surfaces kill various disease-causing bacteria, fungi, viruses, preventing the spread antibiotic resistance through horizontal gene transfer between pathogens. However, there little knowledge about specific targets toxicity in bacteria. Here we show inhibits peptidoglycan LD-transpeptidases, causing higher permeability outermembrane precluding strains Escherichia coli Enterococcus...
Peptidoglycan polymerization complexes contain multimodular penicillin-binding proteins (PBP) of classes A and B that associate a conserved C-terminal transpeptidase module to an N-terminal glycosyltransferase or morphogenesis module, respectively. In Enterococcus faecalis, class PBP5 mediates intrinsic resistance the cephalosporin beta-lactam antibiotics, such as ceftriaxone. To identify partner(s) PBP5, combinations deletions were introduced in all three PBP genes E. faecalis JH2-2 (ponA,...
We report here the first direct assessment of specificity a class peptidoglycan cross-linking enzymes, l,d-transpeptidases, for highly diverse structure precursors Gram-positive bacteria. The lone functionally characterized member this new family active site cysteine peptidases, Ldtfm from Enterococcus faecium, was previously shown to bypass d,d-transpeptidase activity classical penicillin-binding proteins leading high level cross-resistance glycopeptide and β-lactam antibiotics. homologues...
D-aspartate ligase has remained the last unidentified peptide bond-forming enzyme in peptidoglycan assembly pathway of Gram-positive bacteria. Here we show that a two-gene cluster Enterococcus faecium encodes aspartate racemase (Racfm) and (Aslfm) for incorporation D-Asp into side chain precursor. Aslfm was identified as new member ATP-grasp protein superfamily, which includes diverse set enzymes catalyzing ATP-dependent carboxylate-amine ligation reactions. specifically ligated...
The role(s) in cell division of the Mycobacterium tuberculosis Rv0011c gene product, a homolog Streptomyces CrgA protein that is responsible for coordinating growth and cytokinesis sporogenic aerial hyphae, largely unknown. We show an enhanced cyan fluorescent protein-M. (ECFP-CrgA(MT)) fusion localized to membrane, midcell, pole regions smegmatis. Furthermore, ECFP-CrgA(MT) colocalized with FtsZ-enhanced yellow (EYFP) M. Bacterial two-hybrid assays indicated strong interactions FtsZ, FtsQ,...
Active-site serine D,D-transpeptidases belonging to the penicillin-binding protein family (PBPs) have been considered for a long time as essential peptidoglycan cross-linking in all bacteria. However, bypass of PBPs by an L,D-transpeptidase (Ldtfm) conveys high-level resistance β-lactams penam class Enterococcus faecium with minimal inhibitory concentration (MIC) ampicillin >2,000 µg/ml. Unexpectedly, Ldtfm does not confer carbapenem (imipenem MIC = 0.5 µg/ml) whereas cephems display...
The bacterial cell wall peptidoglycan contains unusual l- and d-amino acids assembled as branched peptides. Insight into the biosynthesis of polymer has been hampered by limited access to substrates suitable polymerization assays. Here we report full synthesis peptide stem precursors from two pathogenic bacteria, Enterococcus faecium Mycobacterium tuberculosis, development a sensitive post-derivatization assay for their cross-linking l,d-transpeptidases. Access series peptides showed that...
Mycobacterium tuberculosis and abscessus produce broad-spectrum class A β-lactamases, BlaC Bla Mab , which are inhibited by clavulanate avibactam, respectively. differs from at Ambler position 132 in the conserved motif SDN (SDG versus SDN, respectively). Here, we investigated whether this polymorphism could account for inhibition specificity of β-lactamases slowly rapidly growing mycobacteria.Enzyme kinetics were determined to assess impact substitutions G N on β-lactamase avibactam. The...
Enterococcus faecalis produces a specific penicillin-binding protein (PBP5) that mediates high-level resistance to the cephalosporin class of beta-lactam antibiotics. Deletion locus encoding previously uncharacterized two-component regulatory system E. (croRS) led 4,000-fold reduction in MIC expanded-spectrum ceftriaxone. The cytoplasmic domain sensor kinase (CroS) was purified and shown catalyze ATP-dependent autophosphorylation followed by transfer phosphate mated response regulator...
The intrinsic resistance of Mycobacterium tuberculosis to the β-lactam class antibiotics arises from a chromosomally encoded, extended spectrum, A β-lactamase, BlaC. Herein, we report X-ray crystallographic structure BlaC inhibited with clavulanate at resolution 1.7 Å an R-factor value 0.180 and R-free 0.212 for m/z +154 clavulanate-derived fragment observed in active site. Structural evidence reveals presence hydrogen bonds C1 carbonyl along coplanar arrangement C1, C2, C3, N4, which favors...
Peptidoglycan is predominantly cross-linked by serine DD-transpeptidases in most bacterial species. The enzymes are the essential targets of β-lactam antibiotics. However, unrelated cysteine LD-transpeptidases have been recently recognized as a predominant mode peptidoglycan cross-linking Mycobacterium tuberculosis and bypass mechanism conferring resistance to all β-lactams, except carbapenems such imipenem, Enterococcus faecium. Investigation inhibition this new target showed that acylation...
ABSTRACT The production of β-lactamases Bla Mab and BlaC contributes to β-lactam resistance in Mycobacterium abscessus tuberculosis , respectively. Ceftaroline was efficiently hydrolyzed by these enzymes. Inhibition M. clavulanate decreased the ceftaroline MIC from ≥256 16 64 μg/ml, but values are clinically irrelevant. In contrast, ceftaroline-avibactam combination should be evaluated against since it inhibited growth at lower potentially achievable drug concentrations.
We report characterization of a methicillin-susceptible, vancomycin-resistant bloodstream isolate Staphylococcus aureus recovered from patient in Brazil. Emergence vancomycin resistance methicillin-susceptible S. would indicate that this trait might be poised to disseminate more rapidly among and represents major public health threat.