title: Cephalosporin-NO-donor prodrug PYRRO-C3D shows β-lactam-mediated activity against Streptococcus pneumoniae biofilms.
abstract: Bacterial biofilms show high tolerance towards antibiotics and are a significant problem in clinical settings where they are a primary cause of chronic infections. Novel therapeutic strategies are needed to improve anti-biofilm efficacy and support reduction in antibiotic use. Treatment with exogenous nitric oxide (NO) has been shown to modulate bacterial signaling and metabolic processes that render biofilms more susceptible to antibiotics. We previously reported on cephalosporin-3'-diazeniumdiolates (C3Ds) as NO-donor prodrugs designed to selectively deliver NO to bacterial infection sites following reaction with β-lactamases. With structures based on cephalosporins, C3Ds could, in principal, also be triggered to release NO following β-lactam cleavage mediated by transpeptidases/penicillin-binding proteins (PBPs), the antibacterial target of cephalosporin antibiotics. Transpeptidase-reactive C3Ds could potentially show both NO-mediated anti-biofilm properties and intrinsic (β-lactam-mediated) antibacterial effects. This dual-activity concept was explored using Streptococcus pneumoniae, a species that lacks β-lactamases but relies on transpeptidases for cell-wall synthesis. Treatment with PYRRO-C3D (a representative C3D containing the diazeniumdiolate NO donor PYRRO-NO) was found to significantly reduce viability of planktonic and biofilm pneumococci, demonstrating that C3Ds can elicit direct, cephalosporin-like antibacterial activity in the absence of β-lactamases. While NO release from PYRRO-C3D in the presence of pneumococci was confirmed, the anti-pneumococcal action of the compound was shown to arise exclusively from the β-lactam component and not through NO-mediated effects. The compound showed similar potency to amoxicillin against S. pneumoniae biofilms and greater efficacy than azithromycin, highlighting the potential of C3Ds as new agents for treating pneumococcal infections.
authors.affiliation: Clinical and Experimental Sciences, Faculty of Medicine and Institute for Life Sciences, University of Southampton, Southampton, UK; Southampton NIHR Wellcome Trust Clinical Research Facility, University Hospital Southampton NHS Foundation Trust, Southampton, UK. Electronic address: r.allan@soton.ac.uk.
authors.forename: Raymond N
authors.initials: RN
authors.lastname: Allan
authors.affiliation: Illawarra Health and Medical Research Institute, School of Chemistry, University of Wollongong, Wollongong, NSW, Australia. Electronic address: mkelso@uow.edu.au.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Kelso
authors.affiliation: Illawarra Health and Medical Research Institute, School of Chemistry, University of Wollongong, Wollongong, NSW, Australia. Electronic address: arineh@uow.edu.au.
authors.forename: Ardeshir
authors.initials: A
authors.lastname: Rineh
authors.affiliation: Illawarra Health and Medical Research Institute, School of Chemistry, University of Wollongong, Wollongong, NSW, Australia. Electronic address: nageshwar.yepuri@ansto.gov.au.
authors.forename: Nageshwar R
authors.initials: NR
authors.lastname: Yepuri
authors.affiliation: Clinical and Experimental Sciences, Faculty of Medicine and Institute for Life Sciences, University of Southampton, Southampton, UK; Southampton NIHR Respiratory Biomedical Research Unit, University Hospital Southampton NHS Foundation Trust, Southampton, UK. Electronic address: M.Feelisch@soton.ac.uk.
authors.forename: Martin
authors.initials: M
authors.lastname: Feelisch
authors.affiliation: Biological Sciences and Institute for Life Sciences, University of Southampton, Southampton, UK. Electronic address: os3c14@soton.ac.uk.
authors.forename: Odel
authors.initials: O
authors.lastname: Soren
authors.affiliation: Clinical and Experimental Sciences, Faculty of Medicine and Institute for Life Sciences, University of Southampton, Southampton, UK. Electronic address: sbm1g10@soton.ac.uk.
authors.forename: Sanjita
authors.initials: S
authors.lastname: Brito-Mutunayagam
authors.affiliation: Clinical and Experimental Sciences, Faculty of Medicine and Institute for Life Sciences, University of Southampton, Southampton, UK; Southampton NIHR Respiratory Biomedical Research Unit, University Hospital Southampton NHS Foundation Trust, Southampton, UK; University Hospital Southampton NHS Foundation Trust, Southampton, UK. Electronic address: Rami.Salib@uhs.nhs.uk.
authors.forename: Rami J
authors.initials: RJ
authors.lastname: Salib
authors.affiliation: Biological Sciences and Institute for Life Sciences, University of Southampton, Southampton, UK; Department of Microbial Infection and Immunity, Centre for Microbial Interface Biology, College of Medicine, The Ohio State University, Columbus, OH, USA. Electronic address: Paul.Stoodley@osumc.edu.
authors.forename: Paul
authors.initials: P
authors.lastname: Stoodley
authors.affiliation: Clinical and Experimental Sciences, Faculty of Medicine and Institute for Life Sciences, University of Southampton, Southampton, UK; Southampton NIHR Respiratory Biomedical Research Unit, University Hospital Southampton NHS Foundation Trust, Southampton, UK. Electronic address: S.C.Clarke@soton.ac.uk.
authors.forename: Stuart C
authors.initials: SC
authors.lastname: Clarke
authors.affiliation: Southampton NIHR Respiratory Biomedical Research Unit, University Hospital Southampton NHS Foundation Trust, Southampton, UK; Biological Sciences and Institute for Life Sciences, University of Southampton, Southampton, UK. Electronic address: J.S.Webb@soton.ac.uk.
authors.forename: Jeremy S
authors.initials: JS
authors.lastname: Webb
authors.affiliation: Clinical and Experimental Sciences, Faculty of Medicine and Institute for Life Sciences, University of Southampton, Southampton, UK; Department of Microbial Infection and Immunity, Centre for Microbial Interface Biology, College of Medicine, The Ohio State University, Columbus, OH, USA. Electronic address: Luanne.Hall-Stoodley@osumc.edu.
authors.forename: Luanne
authors.initials: L
authors.lastname: Hall-Stoodley
authors.affiliation: Clinical and Experimental Sciences, Faculty of Medicine and Institute for Life Sciences, University of Southampton, Southampton, UK; Southampton NIHR Wellcome Trust Clinical Research Facility, University Hospital Southampton NHS Foundation Trust, Southampton, UK; Southampton NIHR Respiratory Biomedical Research Unit, University Hospital Southampton NHS Foundation Trust, Southampton, UK. Electronic address: s.faust@soton.ac.uk.
authors.forename: Saul N
authors.initials: SN
authors.lastname: Faust
mesh_terms: D000658:Amoxicillin / Q000494:pharmacology; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000737:chemistry / Q000494:pharmacology*; D017963:Azithromycin / Q000494:pharmacology; D001391:Azo Compounds / Q000737:chemistry / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects*; D002511:Cephalosporins / Q000737:chemistry / Q000494:pharmacology*; D009569:Nitric Oxide / Q000032:analysis; D020030:Nitric Oxide Donors / Q000737:chemistry / Q000494:pharmacology*; D010405:Penicillinase / Q000737:chemistry; D010933:Plankton / Q000382:microbiology; D011355:Prodrugs / Q000737:chemistry / Q000494:pharmacology*; D013296:Streptococcus pneumoniae / Q000187:drug effects*
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D001391:Azo Compounds; D002511:Cephalosporins; D020030:Nitric Oxide Donors; C000625185:PYRRO-C3D; D011355:Prodrugs; D009569:Nitric Oxide; D000658:Amoxicillin; D017963:Azithromycin; D010405:Penicillinase
keywords: Antibiotic resistance; Biofilm; Cephalosporin-NO-Donor; Nitric oxide; Streptococcus pneumoniae