scholarly journals Role of PBPD1 in Stimulation of Listeria monocytogenes Biofilm Formation by Subminimal Inhibitory β-Lactam Concentrations

2014 ◽  
Vol 58 (11) ◽  
pp. 6508-6517 ◽  
Author(s):  
Uyen T. Nguyen ◽  
Hanjeong Harvey ◽  
Andrew J. Hogan ◽  
Alexandria C. F. Afonso ◽  
Gerard D. Wright ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Biofilm Formation ◽  
Regulatory System ◽  
Content Type ◽  
Food Borne ◽  
Approved Drugs ◽  
Biofilm Development ◽  
Fda Approved Drugs ◽  
Stimulation Of

ABSTRACTDisinfectant-tolerantListeria monocytogenesbiofilms can colonize surfaces that come into contact with food, leading to contamination and, potentially, food-borne illnesses. To better understand the process ofL. monocytogenesbiofilm formation and dispersal, we screened 1,120 off-patent FDA-approved drugs and identified several that modulateListeriabiofilm 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-weightd,d-carboxypeptidase. Compared to the wild type, apbpD1mutant 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 ofL. monocytogenesbiofilms shows that the specific set of PBPs that are inactivated by a particular drug dictates whether a protective biofilm response is provoked.

scholarly journals Sodium Lactate Negatively Regulates Shewanella putrefaciens CN32 Biofilm Formation via a Three-Component Regulatory System (LrbS-LrbA-LrbR)

2017 ◽  
Vol 83 (14) ◽  
Author(s):  
Cong Liu ◽  
Jinshui Yang ◽  
Liang Liu ◽  
Baozhen Li ◽  
Hongli Yuan ◽  
...  
Keyword(s):  
Carbon Source ◽  
Biofilm Formation ◽  
Present Report ◽  
Carbon Sources ◽  
Regulatory System ◽  
Shewanella Putrefaciens ◽  
Sodium Lactate ◽  
Signal Molecule ◽  
Content Type ◽  
Biofilm Development

ABSTRACT The capability of biofilm formation has a major impact on the industrial and biotechnological applications of Shewanella putrefaciens CN32. However, the detailed regulatory mechanisms underlying biofilm formation in this strain remain largely unknown. In the present report, we describe a three-component regulatory system which negatively regulates the biofilm formation of S. putrefaciens CN32. This system consists of a histidine kinase LrbS (Sputcn32_0303) and two cognate response regulators, including a transcription factor, LrbA (Sputcn32_0304), and a phosphodiesterase, LrbR (Sputcn32_0305). LrbS responds to the signal of the carbon source sodium lactate and subsequently activates LrbA. The activated LrbA then promotes the expression of lrbR, the gene for the other response regulator. The bis-(3′-5′)-cyclic dimeric GMP (c-di-GMP) phosphodiesterase LrbR, containing an EAL domain, decreases the concentration of intracellular c-di-GMP, thereby negatively regulating biofilm formation. In summary, the carbon source sodium lactate acts as a signal molecule that regulates biofilm formation via a three-component regulatory system (LrbS-LrbA-LrbR) in S. putrefaciens CN32. IMPORTANCE Biofilm formation is a significant capability used by some bacteria to survive in adverse environments. Numerous environmental factors can affect biofilm formation through different signal transduction pathways. Carbon sources are critical nutrients for bacterial growth, and their concentrations and types significantly influence the biomass and structure of biofilms. However, knowledge about the underlying mechanism of biofilm formation regulation by carbon source is still limited. This work elucidates a modulation pattern of biofilm formation negatively regulated by sodium lactate as a carbon source via a three-component regulatory system in S. putrefaciens CN32, which may serve as a good example for studying how the carbon sources impact biofilm development in other bacteria.

scholarly journals A Drug Repositioning Approach Reveals that Streptococcus mutans Is Susceptible to a Diverse Range of Established Antimicrobials and Nonantibiotics

2017 ◽  
Vol 62 (1) ◽  
Author(s):  
S. Saputo ◽  
R. C. Faustoferri ◽  
R. G. Quivey
Keyword(s):  
Streptococcus Mutans ◽  
Biofilm Formation ◽  
Drug Repositioning ◽  
Drug Screen ◽  
Biofilm Inhibition ◽  
Diverse Range ◽  
Content Type ◽  
Multispecies Biofilm ◽  
Approved Drugs ◽  
Fda Approved Drugs

ABSTRACT Streptococcus mutans is the primary causative agent of dental caries and contributes to the multispecies biofilm known as dental plaque. An adenylate kinase-based assay was optimized for S. mutans to detect cell lysis when exposed to the Selleck library (Selleck Chemical, Houston, TX) of 853 FDA-approved drugs in, to our knowledge, the first high-throughput drug screen in S. mutans. We found 126 drugs with activity against S. mutans planktonic cultures, and they were classified into six categories: antibacterials (61), antineoplastics (23), ion channel effectors (9), other antimicrobials (7), antifungals (6), and other (20). These drugs were also tested for activity against S. mutans biofilm cultures, and 24 compounds were found to inhibit biofilm formation, 6 killed preexisting biofilms, 84 exhibited biofilm inhibition and killing activity, and 12 had no activity against biofilms. The activities of 9 selected compounds that exhibited antimicrobial activity were further characterized for their activity against S. mutans planktonic and biofilm cultures. Together, our results suggest that S. mutans exhibits a susceptibility profile to a diverse array of established and novel antibacterials.

scholarly journals Role of Extracellular DNA during Biofilm Formation by Listeria monocytogenes

2010 ◽  
Vol 76 (7) ◽  
pp. 2271-2279 ◽  
Author(s):  
Morten Harmsen ◽  
Martin Lappann ◽  
Susanne Kn�chel ◽  
S�ren Molin
Keyword(s):  
Listeria Monocytogenes ◽  
Biofilm Formation ◽  
Extracellular Dna ◽  
Central Component ◽  
High Molecular Weight Dna ◽  
Food Borne ◽  
Attachment Sites ◽  
Sperm Dna ◽  
Salmon Sperm Dna

ABSTRACT Listeria monocytogenes is a food-borne pathogen that is capable of living in harsh environments. It is believed to do this by forming biofilms, which are surface-associated multicellular structures encased in a self-produced matrix. In this paper we show that in L. monocytogenes extracellular DNA (eDNA) may be the only central component of the biofilm matrix and that it is necessary for both initial attachment and early biofilm formation for 41 L. monocytogenes strains that were tested. DNase I treatment resulted in dispersal of biofilms, not only in microtiter tray assays but also in flow cell biofilm assays. However, it was also demonstrated that in a culture without eDNA, neither Listeria genomic DNA nor salmon sperm DNA by itself could restore the capacity to adhere. A search for additional necessary components revealed that peptidoglycan (PG), specifically N-acetylglucosamine (NAG), interacted with the DNA in a manner which restored adhesion. If a short DNA fragment (less than approximately 500 bp long) was added to an eDNA-free culture prior to addition of genomic or salmon sperm DNA, adhesion was prevented, indicating that high-molecular-weight DNA is required for adhesion and that the number of attachment sites on the cell surface can be saturated.

scholarly journals Novel Role for the Streptococcus pneumoniae Toxin Pneumolysin in the Assembly of Biofilms

mBio ◽  
2013 ◽  
Vol 4 (5) ◽  
Author(s):  
Joshua R. Shak ◽  
Herbert P. Ludewick ◽  
Kristen E. Howery ◽  
Fuminori Sakai ◽  
Hong Yi ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Hemolytic Activity ◽  
Biofilm Formation ◽  
Early Time ◽  
Wild Type ◽  
Knockout Mutant ◽  
Content Type ◽  
Biofilm Development ◽  
Almost All

ABSTRACTStreptococcus pneumoniaeis an important commensal and pathogen responsible for almost a million deaths annually in children under five. The formation of biofilms byS. pneumoniaeis important in nasopharyngeal colonization, pneumonia, and otitis media. Pneumolysin (Ply) is a toxin that contributes significantly to the virulence ofS. pneumoniaeand is an important candidate as a serotype-independent vaccine target. Having previously demonstrated that aluxSknockout mutant was unable to form early biofilms and expressed lessplymRNA than the wild type, we conducted a study to investigate the role of Ply in biofilm formation. We found that Ply was expressed in early phases of biofilm development and localized to cellular aggregates as early as 4 h postinoculation.S. pneumoniae plyknockout mutants in D39 and TIGR4 backgrounds produced significantly less biofilm biomass than wild-type strains at early time points, both on polystyrene and on human respiratory epithelial cells, cultured under static or continuous-flow conditions. Ply’s role in biofilm formation appears to be independent of its hemolytic activity, asS. pneumoniaeserotype 1 strains, which produce a nonhemolytic variant of Ply, were still able to form biofilms. Transmission electron microscopy of biofilms grown on A549 lung cells using immunogold demonstrated that Ply was located both on the surfaces of pneumococcal cells and in the extracellular biofilm matrix. Altogether, our studies demonstrate a novel role for pneumolysin in the assembly ofS. pneumoniaebiofilms that is likely important during both carriage and disease and therefore significant for pneumolysin-targeting vaccines under development.IMPORTANCEThe bacteriumStreptococcus pneumoniae(commonly known as the pneumococcus) is commonly carried in the human nasopharynx and can spread to other body sites to cause disease. In the nasopharynx, middle ear, and lungs, the pneumococcus forms multicellular surface-associated structures called biofilms. Pneumolysin is an important toxin produced by almost allS. pneumoniaestrains, extensively studied for its ability to cause damage to human tissue. In this paper, we demonstrate that pneumolysin has a previously unrecognized role in biofilm formation by showing that strains without pneumolysin are unable to form the same amount of biofilm on plastic and human cell substrates. Furthermore, we show that the role of pneumolysin in biofilm formation is separate from the hemolytic activity responsible for tissue damage during pneumococcal diseases. This novel role for pneumolysin suggests that pneumococcal vaccines directed against this protein should be investigated for their potential impact on biofilms formed during carriage and disease.

scholarly journals Loss of Flagellum-Based Motility by Listeria monocytogenes Results in Formation of Hyperbiofilms

2008 ◽  
Vol 190 (17) ◽  
pp. 6030-6034 ◽  
Author(s):  
Tatsaporn Todhanakasem ◽  
Glenn M. Young
Keyword(s):  
Listeria Monocytogenes ◽  
Biofilm Formation ◽  
High Density ◽  
Gram Positive ◽  
Surface Attachment ◽  
Bacterial Surface ◽  
Food Borne ◽  
Biofilm Development

ABSTRACT Biofilm formation by the gram-positive, motile, food-borne pathogen Listeria monocytogenes was demonstrated to occur by an ordered series of stages. Biofilm development involves flagellum-based motility, which when blocked decreases initial bacterial surface attachment but subsequently leads to the formation of hyperbiofilms, surface-attached communities reaching high density.

scholarly journals Role ofrpoSin Escherichia coli O157:H7 Strain H32 Biofilm Development and Survival

2012 ◽  
Vol 78 (23) ◽  
pp. 8331-8339 ◽  
Author(s):  
Jessica R. Sheldon ◽  
Mi-Sung Yim ◽  
Jessica H. Saliba ◽  
Wai-Hong Chung ◽  
Kwok-Yin Wong ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Lake Water ◽  
Biofilm Formation ◽  
Survival Rates ◽  
Confocal Scanning Laser Microscopy ◽  
Wild Type ◽  
Minimal Growth ◽  
Content Type ◽  
Biofilm Development

ABSTRACTThe protein RpoS is responsible for mediating cell survival during the stationary phase by conferring cell resistance to various stressors and has been linked to biofilm formation. In this study, the role of therpoSgene inEscherichia coliO157:H7 biofilm formation and survival in water was investigated. Confocal scanning laser microscopy of biofilms established on coverslips revealed a nutrient-dependent role ofrpoSin biofilm formation, where the biofilm biomass volume of therpoSmutant was 2.4- to 7.5-fold the size of itsrpoS+wild-type counterpart in minimal growth medium. The enhanced biofilm formation of therpoSmutant did not, however, translate to increased survival in sterile double-distilled water (ddH2O), filter-sterilized lake water, or unfiltered lake water. TherpoSmutant had an overall reduction of 3.10 and 5.30 log10in sterile ddH2O and filter-sterilized lake water, respectively, while only minor reductions of 0.53 and 0.61 log10in viable counts were observed for the wild-type form in the two media over a 13-day period, respectively. However, the survival rates of the detached biofilm-derivedrpoS+andrpoSmutant cells were comparable. Under the competitive stress conditions of unfiltered lake water, the advantage conferred by the presence ofrpoSwas lost, and both the wild-type and knockout forms displayed similar declines in viable counts. These results suggest thatrpoSdoes have an influence on both biofilm formation and survival ofE. coliO157:H7 and that the advantage conferred byrpoSis contingent on the environmental conditions.

scholarly journals σBInhibits Poly-N-Acetylglucosamine Exopolysaccharide Synthesis and Biofilm Formation inStaphylococcus aureus

2019 ◽  
Vol 201 (11) ◽  
Author(s):  
Jaione Valle ◽  
Maite Echeverz ◽  
Iñigo Lasa
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Flow Conditions ◽  
Content Type ◽  
Environmental Signals ◽  
General Stress Response ◽  
Biofilm Development ◽  
Type Strains ◽  
Complex Regulatory Network

ABSTRACTStaphylococcus aureusclinical strains are able to produce at least two distinct types of biofilm matrixes: biofilm matrixes made of the polysaccharide intercellular adhesin (PIA) or poly-N-acetylglucosamine (PNAG), whose synthesis is mediated by theicaADBClocus, and biofilm matrixes built of proteins (polysaccharide independent). σBis a conserved alternative sigma factor that regulates the expression of more than 100 genes in response to changes in environmental conditions. While numerous studies agree that σBis required for polysaccharide-independent biofilms, controversy persists over the role of σBin the regulation of PIA/PNAG-dependent biofilm development. Here, we show that genetically unrelatedS. aureusσB-deficient strains produced stronger biofilms under both static and flow conditions and accumulated higher levels of PIA/PNAG exopolysaccharide than their corresponding wild-type strains. The increased accumulation of PIA/PNAG in the σBmutants correlated with a greater accumulation of the IcaC protein showed that it was not due to adjustments inicaADBCoperon transcription and/oricaADBCmRNA stability. Overall, our results reveal that in the presence of active σB, the turnover of Ica proteins is accelerated, reducing the synthesis of PIA/PNAG exopolysaccharide and consequently the PIA/PNAG-dependent biofilm formation capacity.IMPORTANCEDue to its multifaceted lifestyle,Staphylococcus aureusneeds a complex regulatory network to connect environmental signals with cellular physiology. One particular transcription factor, named σB(SigB), is involved in the general stress response and the expression of virulence factors. For many years, great confusion has existed about the role of σBin the regulation of the biofilm lifestyle inS. aureus. Our study demonstrated that σBis not necessary for exopolysaccharide-dependent biofilms and, even more, thatS. aureusproduces stronger biofilms in the absence of σB. The increased accumulation of exopolysaccharide correlates with higher stability of the proteins responsible for its synthesis. The present findings reveal an additional regulatory layer to control biofilm exopolysaccharide synthesis under stress conditions.

scholarly journals Small-Molecule Modulators of Listeria monocytogenes Biofilm Development

2011 ◽  
Vol 78 (5) ◽  
pp. 1454-1465 ◽  
Author(s):  
Uyen T. Nguyen ◽  
Iwona B. Wenderska ◽  
Matthew A. Chong ◽  
Kalinka Koteva ◽  
Gerard D. Wright ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Listeria Monocytogenes ◽  
Protein Kinase ◽  
Biofilm Formation ◽  
De Novo ◽  
Saturated Fatty Acids ◽  
Antibiofilm Activity ◽  
Dependent Manner ◽  
Content Type ◽  
Biofilm Development

ABSTRACTListeria monocytogenesis an important food-borne pathogen whose ability to form disinfectant-tolerant biofilms on a variety of surfaces presents a food safety challenge for manufacturers of ready-to-eat products. We developed here a high-throughput biofilm assay forL. monocytogenesand, as a proof of principle, used it to screen an 80-compound protein kinase inhibitor library to identify molecules that perturb biofilm development. The screen yielded molecules toxic to multiple strains ofListeriaat micromolar concentrations, as well as molecules that decreased (≤50% of vehicle control) or increased (≥200%) biofilm formation in a dose-dependent manner without affecting planktonic cell density. Toxic molecules—including the protein kinase C antagonist sphingosine—had antibiofilm activity at sub-MIC concentrations. Structure-activity studies of the biofilm inhibitory compound palmitoyl-d,l-carnitine showed that whileListeriabiofilm formation was inhibited with a 50% inhibitory concentration of 5.85 ± 0.24 μM,d,l-carnitine had no effect, whereas palmitic acid had stimulatory effects. Saturated fatty acids between C9:0and C14:0wereListeriabiofilm inhibitors, whereas fatty acids of C16:0or longer were stimulators, showing chain length specificity.De novo-synthesized short-chain acyl carnitines were less effective biofilm inhibitors than the palmitoyl forms. These molecules, whose activities against bacteria have not been previously established, are both useful probes ofL. monocytogenesbiology and promising leads for the further development of antibiofilm strategies.

scholarly journals Role of quorum sensing in UVA-induced biofilm formation in Pseudomonas aeruginosa

Microbiology ◽  
2020 ◽  
Vol 166 (8) ◽  
pp. 735-750 ◽  
Author(s):  
Magdalena Pezzoni ◽  
Ramón A. Pizarro ◽  
Cristina S. Costa
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Biofilm Formation ◽  
Type Species ◽  
Transcriptional Level ◽  
Content Type ◽  
Link Type ◽  
Opportunistic Human Pathogen ◽  
Biofilm Development

Pseudomonas aeruginosa , a versatile bacterium present in terrestrial and aquatic environments and a relevant opportunistic human pathogen, is largely known for the production of robust biofilms. The unique properties of these structures complicate biofilm eradication, because they make the biofilms very resistant to diverse antibacterial agents. Biofilm development and establishment is a complex process regulated by multiple regulatory genetic systems, among them is quorum sensing (QS), a mechanism employed by bacteria to regulate gene transcription in response to population density. In addition, environmental factors such as UVA radiation (400–315 nm) have been linked to biofilm formation. In this work, we further investigate the mechanism underlying the induction of biofilm formation by UVA, analysing the role of QS in this phenomenon. We demonstrate that UVA induces key genes of the Las and Rhl QS systems at the transcriptional level. We also report that pelA and pslA genes, which are essential for biofilm formation and whose transcription depends in part on QS, are significantly induced under UVA exposure. Finally, the results demonstrate that in a relA strain (impaired for ppGpp production), the UVA treatment does not induce biofilm formation or QS genes, suggesting that the increase of biofilm formation due to exposure to UVA in P. aeruginosa could rely on a ppGpp-dependent QS induction.

scholarly journals Rcs Phosphorelay Activation in Cardiolipin-DeficientEscherichia coliReduces Biofilm Formation

2019 ◽  
Vol 201 (9) ◽  
Author(s):  
Julia F. Nepper ◽  
Yin C. Lin ◽  
Douglas B. Weibel
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Lipid Membrane ◽  
Protein Translocation ◽  
Membrane Composition ◽  
Anionic Phospholipid ◽  
Content Type ◽  
Envelope Stress ◽  
Biofilm Development

ABSTRACTBiofilm formation is a complex process that requires a number of transcriptional, proteomic, and physiological changes to enable bacterial survival. The lipid membrane presents a barrier to communication between the machinery within bacteria and the physical and chemical features of their extracellular environment, and yet little is known about how the membrane influences biofilm development. We found that depleting the anionic phospholipid cardiolipin reduces biofilm formation inEscherichia colicells by as much as 50%. The absence of cardiolipin activates the regulation of colanic acid synthesis (Rcs) envelope stress response, which represses the production of flagella, disrupts initial biofilm attachment, and reduces biofilm growth. We demonstrate that a reduction in the concentration of cardiolipin impairs translocation of proteins across the inner membrane, which we hypothesize activates the Rcs pathway through the outer membrane lipoprotein RcsF. Our study demonstrates a molecular connection between the composition of membrane phospholipids and biofilm formation inE. coliand suggests that altering lipid biosynthesis may be a viable approach for altering biofilm formation and possibly other multicellular phenotypes related to bacterial adaptation and survival.IMPORTANCEThere is a growing interest in the role of lipid membrane composition in the physiology and adaptation of bacteria. We demonstrate that a reduction in the anionic phospholipid cardiolipin impairs biofilm formation inEscherichia colicells. Depleting cardiolipin reduced protein translocation across the inner membrane and activated the Rcs envelope stress response. Consequently, cardiolipin depletion produced cells lacking assembled flagella, which impacted their ability to attach to surfaces and seed the earliest stage in biofilm formation. This study provides empirical evidence for the role of anionic phospholipid homeostasis in protein translocation and its effect on biofilm development and highlights modulation of the membrane composition as a potential method of altering bacterial phenotypes related to adaptation and survival.

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