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Galley NF, Greetham D, Alamán-Zárate MG, Williamson MP, Evans CA, Spittal WD, Buddle JE, Freeman J, Davis GL, Dickman MJ, Wilcox MH, Lovering AL, Fagan RP, Mesnage S. Clostridioides difficile canonical L,D-transpeptidases catalyze a novel type of peptidoglycan cross-links and are not required for beta-lactam resistance. J Biol Chem 2024; 300:105529. [PMID: 38043796 PMCID: PMC10792238 DOI: 10.1016/j.jbc.2023.105529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 11/19/2023] [Accepted: 11/27/2023] [Indexed: 12/05/2023] Open
Abstract
Clostridioides difficile is the leading cause of antibiotic-associated diarrhea worldwide with significant morbidity and mortality. This organism is naturally resistant to several beta-lactam antibiotics that inhibit the polymerization of peptidoglycan, an essential component of the bacteria cell envelope. Previous work has revealed that C. difficile peptidoglycan has an unusual composition. It mostly contains 3-3 cross-links, catalyzed by enzymes called L,D-transpeptidases (Ldts) that are poorly inhibited by beta-lactams. It was therefore hypothesized that peptidoglycan polymerization by these enzymes could underpin antibiotic resistance. Here, we investigated the catalytic activity of the three canonical Ldts encoded by C. difficile (LdtCd1, LdtCd2, and LdtCd3) in vitro and explored their contribution to growth and antibiotic resistance. We show that two of these enzymes catalyze the formation of novel types of peptidoglycan cross-links using meso-diaminopimelic acid both as a donor and an acceptor, also observed in peptidoglycan sacculi. We demonstrate that the simultaneous deletion of these three genes only has a minor impact on both peptidoglycan structure and resistance to beta-lactams. This unexpected result therefore implies that the formation of 3-3 peptidoglycan cross-links in C. difficile is catalyzed by as yet unidentified noncanonical Ldt enzymes.
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Affiliation(s)
- Nicola F Galley
- School of Biosciences, University of Sheffield, Sheffield, UK
| | - Darren Greetham
- School of Biosciences, University of Sheffield, Sheffield, UK
| | | | | | - Caroline A Evans
- Department of Chemical and Biological Engineering, University of Sheffield, Sheffield, UK
| | - William D Spittal
- Department of Microbiology, Leeds Teaching Hospitals NHS Trust, Leeds Institute of Medical Research, University of Leeds, Leeds, UK; Healthcare Associated Infections Research Group, Leeds Institute of Medical Research University of Leeds, Leeds, UK
| | | | - Jane Freeman
- Department of Microbiology, Leeds Teaching Hospitals NHS Trust, Leeds Institute of Medical Research, University of Leeds, Leeds, UK; Healthcare Associated Infections Research Group, Leeds Institute of Medical Research University of Leeds, Leeds, UK
| | - Georgina L Davis
- Department of Microbiology, Leeds Teaching Hospitals NHS Trust, Leeds Institute of Medical Research, University of Leeds, Leeds, UK; Healthcare Associated Infections Research Group, Leeds Institute of Medical Research University of Leeds, Leeds, UK
| | - Mark J Dickman
- Department of Chemical and Biological Engineering, University of Sheffield, Sheffield, UK
| | - Mark H Wilcox
- Department of Microbiology, Leeds Teaching Hospitals NHS Trust, Leeds Institute of Medical Research, University of Leeds, Leeds, UK; Healthcare Associated Infections Research Group, Leeds Institute of Medical Research University of Leeds, Leeds, UK
| | | | - Robert P Fagan
- School of Biosciences, University of Sheffield, Sheffield, UK
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Abstract
Clostridioides difficile is the most common cause of nosocomial antibiotic-associated diarrhea, and is responsible for a spectrum of diseases characterized by high levels of recurrence, morbidity, and mortality. Treatment is complex, since antibiotics constitute both the main treatment and the major risk factor for infection. Worryingly, resistance to multiple antibiotics is becoming increasingly widespread, leading to the classification of this pathogen as an urgent threat to global health. As a consummate opportunist, C. difficile is well equipped for promoting disease, owing to its arsenal of virulence factors: transmission of this anaerobe is highly efficient due to the formation of robust endospores, and an array of adhesins promote gut colonization. C. difficile produces multiple toxins acting upon gut epithelia, resulting in manifestations typical of diarrheal disease, and severe inflammation in a subset of patients. This review focuses on such virulence factors, as well as the importance of antimicrobial resistance and genome plasticity in enabling pathogenesis and persistence of this important pathogen.
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Affiliation(s)
- Jessica E Buddle
- Molecular Microbiology, School of Biosciences, University of Sheffield, Sheffield, UK
| | - Robert P Fagan
- Molecular Microbiology, School of Biosciences, University of Sheffield, Sheffield, UK
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