title: Role of PBPD1 in stimulation of Listeria monocytogenes biofilm formation by subminimal inhibitory β-lactam concentrations.
abstract: Disinfectant-tolerant Listeria monocytogenes biofilms can colonize surfaces that come into contact with food, leading to contamination and, potentially, food-borne illnesses. To better understand the process of L. monocytogenes biofilm formation and dispersal, we screened 1,120 off-patent FDA-approved drugs and identified several that modulate Listeria biofilm development. Among the hits were more than 30 β-lactam antibiotics, with effects ranging from inhibiting (≤50%) to stimulating (≥200%) biofilm formation compared to control. Most β-lactams also dispersed a substantial proportion of established biofilms. This phenotype did not necessarily involve killing, as >50% dispersal could be achieved with concentrations as low as 1/20 of the MIC of some cephalosporins. Penicillin-binding protein (PBP) profiling using a fluorescent penicillin analogue showed similar inhibition patterns for most β-lactams, except that biofilm-stimulatory drugs did not bind PBPD1, a low-molecular-weight d,d-carboxypeptidase. Compared to the wild type, a pbpD1 mutant had an attenuated biofilm response to stimulatory β-lactams. The cephalosporin-responsive CesRK two-component regulatory system, whose regulon includes PBPs, was not required for the response. The requirement for PBPD1 activity for β-lactam stimulation of L. monocytogenes biofilms shows that the specific set of PBPs that are inactivated by a particular drug dictates whether a protective biofilm response is provoked.
authors.affiliation: Department of Biochemistry and Biomedical Sciences and the Michael G. DeGroote Institute for Infectious Diseases Research, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Uyen T
authors.initials: UT
authors.lastname: Nguyen
authors.affiliation: Department of Biochemistry and Biomedical Sciences and the Michael G. DeGroote Institute for Infectious Diseases Research, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Hanjeong
authors.initials: H
authors.lastname: Harvey
authors.affiliation: Department of Biochemistry and Biomedical Sciences and the Michael G. DeGroote Institute for Infectious Diseases Research, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Hogan
authors.affiliation: Department of Biochemistry and Biomedical Sciences and the Michael G. DeGroote Institute for Infectious Diseases Research, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Alexandria C F
authors.initials: AC
authors.lastname: Afonso
authors.affiliation: Department of Biochemistry and Biomedical Sciences and the Michael G. DeGroote Institute for Infectious Diseases Research, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Gerard D
authors.initials: GD
authors.lastname: Wright
authors.affiliation: Department of Biochemistry and Biomedical Sciences and the Michael G. DeGroote Institute for Infectious Diseases Research, McMaster University, Hamilton, Ontario, Canada burrowl@mcmaster.ca.
authors.forename: Lori L
authors.initials: LL
authors.lastname: Burrows
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D018441:Biofilms / Q000187:drug effects*; D002511:Cephalosporins / Q000494:pharmacology; D004202:Disinfectants / Q000494:pharmacology; D024881:Drug Resistance, Bacterial; D055786:Gene Knockout Techniques; D008089:Listeria monocytogenes / Q000187:drug effects*; D008088:Listeriosis / Q000188:drug therapy / Q000382:microbiology; D008826:Microbial Sensitivity Tests; D046915:Penicillin-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics; D047090:beta-Lactams / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D002511:Cephalosporins; C487493:CesR protein, Listeria monocytogenes; D004202:Disinfectants; C000599915:PBPD1 protein, Listeria monocytogenes; D046915:Penicillin-Binding Proteins; D014157:Transcription Factors; D047090:beta-Lactams