scholarly journals Environmental Stress-Induced Bacterial Lysis and Extracellular DNA Release Contribute toCampylobacter jejuniBiofilm Formation

2017 ◽  
Vol 84 (5) ◽  
Author(s):  
Jinsong Feng ◽  
Lina Ma ◽  
Jiatong Nie ◽  
Michael E. Konkel ◽  
Xiaonan Lu
Keyword(s):  
Environmental Stress ◽  
Campylobacter Jejuni ◽  
Biofilm Formation ◽  
Extracellular Dna ◽  
Bacterial Cells ◽  
Starvation Stress ◽  
Content Type ◽  
Bacterial Lysis ◽  
Major Form ◽  
Spatial Locations

ABSTRACTCampylobacter jejuniis a microaerophilic bacterium and is believed to persist in a biofilm to antagonize environmental stress. This study investigated the influence of environmental conditions on the formation ofC. jejunibiofilm. We report an extracellular DNA (eDNA)-mediated mechanism of biofilm formation in response to aerobic and starvation stress. The eDNA was determined to represent a major form of constitutional material ofC. jejunibiofilms and to be closely associated with bacterial lysis. Deletion mutation of the stress response genesspoTandrecAenhanced the aerobic influence by stimulating lysis and increasing eDNA release. Flagella were also involved in biofilm formation but mainly contributed to attachment rather than induction of lysis. The addition of genomic DNA from eitherCampylobacterorSalmonellaresulted in a concentration-dependent stimulation effect on biofilm formation, but the effect was not due to forming a precoating DNA layer. Enzymatic degradation of DNA by DNase I disruptedC. jejunibiofilm. In a dual-species biofilm, eDNA allocatedCampylobacterandSalmonellaat distinct spatial locations that protectCampylobacterfrom oxygen stress. Our findings demonstrated an essential role and multiple functions of eDNA in biofilm formation ofC. jejuni, including facilitating initial attachment, establishing and maintaining biofilm, and allocating bacterial cells.IMPORTANCECampylobacter jejuniis a major cause of foodborne illness worldwide. In the natural environment, the growth ofC. jejuniis greatly inhibited by various forms of environmental stress, such as aerobic stress and starvation stress. Biofilm formation can facilitate the distribution ofC. jejuniby enabling the survival of this fragile microorganism under unfavorable conditions. However, the mechanism ofC. jejunibiofilm formation in response to environmental stress has been investigated only partially. The significance of our research is in identifying extracellular DNA released by bacterial lysis as a major form of constitution material that mediates the formation ofC. jejunibiofilm in response to environmental stress, which enhances our understanding of the formation mechanism ofC. jejunibiofilm. This knowledge can aid the development of intervention strategies to limit the distribution ofC. jejuni.

PBP4 and PBP5 are involved in regulating exopolysaccharide synthesis during Escherichia coli biofilm formation

Microbiology ◽  
2021 ◽  
Vol 167 (3) ◽  
Author(s):  
Sathi Mallick ◽  
Shanti Kiran ◽  
Tapas Kumar Maiti ◽  
Anindya S. Ghosh
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Type Species ◽  
Pentose Phosphate ◽  
Bacterial Cells ◽  
Surface Adhesion ◽  
Content Type ◽  
Penicillin Binding Proteins ◽  
E Coli ◽  
Link Type

Escherichia coli low-molecular-mass (LMM) Penicillin-binding proteins (PBPs) help in hydrolysing the peptidoglycan fragments from their cell wall and recycling them back into the growing peptidoglycan matrix, in addition to their reported involvement in biofilm formation. Biofilms are external slime layers of extra-polymeric substances that sessile bacterial cells secrete to form a habitable niche for themselves. Here, we hypothesize the involvement of Escherichia coli LMM PBPs in regulating the nature of exopolysaccharides (EPS) prevailing in its extra-polymeric substances during biofilm formation. Therefore, this study includes the assessment of physiological characteristics of E. coli CS109 LMM PBP deletion mutants to address biofilm formation abilities, viability and surface adhesion. Finally, EPS from parent CS109 and its ΔPBP4 and ΔPBP5 mutants were purified and analysed for sugars present. Deletions of LMM PBP reduced biofilm formation, bacterial adhesion and their viability in biofilms. Deletions also diminished EPS production by ΔPBP4 and ΔPBP5 mutants, purification of which suggested an increased overall negative charge compared with their parent. Also, EPS analyses from both mutants revealed the appearance of an unusual sugar, xylose, that was absent in CS109. Accordingly, the reason for reduced biofilm formation in LMM PBP mutants may be speculated as the subsequent production of xylitol and a hindrance in the standard flow of the pentose phosphate pathway.

scholarly journals Clarithromycin Exerts an Antibiofilm Effect against Salmonella enterica Serovar Typhimurium rdar Biofilm Formation and Transforms the Physiology towards an Apparent Oxygen-Depleted Energy and Carbon Metabolism

2020 ◽  
Vol 88 (11) ◽  
Author(s):  
Munirah Zafar ◽  
Humera Jahan ◽  
Sulman Shafeeq ◽  
Manfred Nimtz ◽  
Lothar Jänsch ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Salmonella Enterica ◽  
Biofilm Formation ◽  
Antibiofilm Activity ◽  
Bacterial Cells ◽  
Content Type ◽  
Regulatory Pathways ◽  
Heat Shock Stress ◽  
Extracellular Matrix Components ◽  
Serovar Typhimurium

ABSTRACT Upon biofilm formation, production of extracellular matrix components and alteration in physiology and metabolism allows bacteria to build up multicellular communities which can facilitate nutrient acquisition during unfavorable conditions and provide protection toward various forms of environmental stresses to individual cells. Thus, bacterial cells within biofilms become tolerant against antimicrobials and the immune system. In the present study, we evaluated the antibiofilm activity of the macrolides clarithromycin and azithromycin. Clarithromycin showed antibiofilm activity against rdar (red, dry, and rough) biofilm formation of the gastrointestinal pathogen Salmonella enterica serovar Typhimurium ATCC 14028 (Nalr) at a 1.56 μM subinhibitory concentration in standing culture and dissolved cell aggregates at 15 μM in a microaerophilic environment, suggesting that the oxygen level affects the activity of the drug. Treatment with clarithromycin significantly decreased transcription and production of the rdar biofilm activator CsgD, with biofilm genes such as csgB and adrA to be concomitantly downregulated. Although fliA and other flagellar regulon genes were upregulated, apparent motility was downregulated. RNA sequencing showed a holistic cell response upon clarithromycin exposure, whereby not only genes involved in the biofilm-related regulatory pathways but also genes that likely contribute to intrinsic antimicrobial resistance, and the heat shock stress response were differentially regulated. Most significantly, clarithromycin exposure shifted the cells toward an apparent oxygen- and energy-depleted status, whereby the metabolism that channels into oxidative phosphorylation was downregulated, and energy gain by degradation of propane 1,2-diol, ethanolamine and l-arginine catabolism, potentially also to prevent cytosolic acidification, was upregulated. This analysis will allow the subsequent identification of novel intrinsic antimicrobial resistance determinants.

scholarly journals The N-Acetylglucosaminidase LytB of Streptococcus pneumoniae Is Involved in the Structure and Formation of Biofilms

2020 ◽  
Vol 86 (10) ◽  
Author(s):  
Mirian Domenech ◽  
Ernesto García
Keyword(s):  
Streptococcus Pneumoniae ◽  
Biofilm Formation ◽  
Single Gene ◽  
Extracellular Polysaccharide ◽  
Extracellular Dna ◽  
Nasopharyngeal Colonization ◽  
Content Type ◽  
Daughter Cells ◽  
Biofilm Matrix

ABSTRACT The N-acetylglucosaminidase LytB of Streptococcus pneumoniae is involved in nasopharyngeal colonization and is responsible for cell separation at the end of cell division; thus, ΔlytB mutants form long chains of cells. This paper reports the construction and properties of a defective pneumococcal mutant producing an inactive LytB protein (LytBE585A). It is shown that an enzymatically active LytB is required for in vitro biofilm formation, as lytB mutants (either ΔlytB or producing the inactive LytBE585A) are incapable of forming substantial biofilms, despite that extracellular DNA is present in the biofilm matrix. Adding small amounts (0.5 to 2.0 μg/ml) of exogenous LytB or some LytB constructs restored the biofilm-forming capacity of lytB mutants to wild-type levels. The LytBE585A mutant formed biofilm more rapidly than ΔlytB mutants in the presence of LytB. This suggests that the mutant protein acted in a structural role, likely through the formation of complexes with extracellular DNA. The chain-dispersing capacity of LytB allowed the separation of daughter cells, presumably facilitating the formation of microcolonies and, finally, of biofilms. A role for the possible involvement of LytB in the synthesis of the extracellular polysaccharide component of the biofilm matrix is also discussed. IMPORTANCE It has been previously accepted that biofilm formation in S. pneumoniae must be a multigenic trait because the mutation of a single gene has led to only to partial inhibition of biofilm production. In the present study, however, evidence that the N-acetylglucosaminidase LytB is crucial in biofilm formation is provided. Despite the presence of extracellular DNA, strains either deficient in LytB or producing a defective LytB enzyme formed only shallow biofilms.

scholarly journals Pushing beyond the Envelope: the Potential Roles of OprF inPseudomonas aeruginosaBiofilm Formation and Pathogenicity

2019 ◽  
Vol 201 (18) ◽  
Author(s):  
Erin K. Cassin ◽  
Boo Shan Tseng
Keyword(s):  
Extracellular Matrix ◽  
Outer Membrane ◽  
Biofilm Formation ◽  
Matrix Protein ◽  
Cell Envelope ◽  
Outer Membrane Vesicles ◽  
Extracellular Dna ◽  
Future Research ◽  
Content Type ◽  
Biofilm Matrix

ABSTRACTThe ability ofPseudomonas aeruginosato form biofilms, which are communities of cells encased in a self-produced extracellular matrix, protects the cells from antibiotics and the host immune response. While some biofilm matrix components, such as exopolysaccharides and extracellular DNA, are relatively well characterized, the extracellular matrix proteins remain understudied. Multiple proteomic analyses of theP. aeruginosasoluble biofilm matrix and outer membrane vesicles, which are a component of the matrix, have identified OprF as an abundant matrix protein. To date, the few reports on the effects ofoprFmutations on biofilm formation are conflicting, and little is known about the potential role of OprF in the biofilm matrix. The majority of OprF studies focus on the protein as a cell-associated porin. As a component of the outer membrane, OprF assumes dual conformations and is involved in solute transport, as well as cell envelope integrity. Here, we review the current literature on OprF inP. aeruginosa, discussing how the structure and function of the cell-associated and matrix-associated protein may affect biofilm formation and pathogenesis in order to inform future research on this understudied matrix protein.

scholarly journals In VitroEffects of Polyphosphate against Prevotella intermedia in Planktonic Phase and Biofilm

2015 ◽  
Vol 60 (2) ◽  
pp. 818-826 ◽  
Author(s):  
Eun-Young Jang ◽  
Minjung Kim ◽  
Mi Hee Noh ◽  
Ji-Hoi Moon ◽  
Jin-Yong Lee
Keyword(s):  
Biofilm Formation ◽  
Sodium Tripolyphosphate ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Prevotella Intermedia ◽  
Dependent Manner ◽  
Bacterial Cells ◽  
Concentration Dependent Manner ◽  
Content Type ◽  
Planktonic Phase

ABSTRACTPolyphosphate (polyP) has gained a wide interest in the food industry due to its potential as a decontaminating agent. In this study, we examined the effect of sodium tripolyphosphate (polyP3; Na5P3O10) against planktonic and biofilm cells ofPrevotella intermedia, a major oral pathogen. The MIC of polyP3 againstP. intermediaATCC 49046 determined by agar dilution method was 0.075%, while 0.05% polyP3 was bactericidal againstP. intermediain time-kill analysis performed using liquid medium. A crystal violet binding assay for the assessment of biofilm formation byP. intermediashowed that sub-MICs of polyP3 significantly decreased biofilm formation. Under the scanning electron microscope, decreased numbers ofP. intermediacells forming the biofilms were observed when the bacterial cells were incubated with 0.025% or higher concentrations of polyP3. Assessment of biofilm viability with LIVE/DEAD staining and viable cell count methods showed that 0.05% or higher concentrations of polyP3 significantly decreased the viability of the preformed biofilms in a concentration-dependent manner. The zone sizes of alpha-hemolysis formed on horse blood agar produced byP. intermediawere decreased in the presence of polyP3. The expression of the genes encoding hemolysins and the genes of the hemin uptake (hmu) locus was downregulated by polyP3. Collectively, our results show that polyP is an effective antimicrobial agent againstP. intermediain biofilms as well as planktonic phase, interfering with the process of hemin acquisition by the bacterium.

scholarly journals Chicken Juice Enhances Surface Attachment and Biofilm Formation of Campylobacter jejuni

2014 ◽  
Vol 80 (22) ◽  
pp. 7053-7060 ◽  
Author(s):  
Helen L. Brown ◽  
Mark Reuter ◽  
Louise J. Salt ◽  
Kathryn L. Cross ◽  
Roy P. Betts ◽  
...  
Keyword(s):  
Campylobacter Jejuni ◽  
Food Chain ◽  
Biofilm Formation ◽  
Cell Attachment ◽  
Bacterial Attachment ◽  
Poultry Meat ◽  
Abiotic Surface ◽  
Surface Attachment ◽  
Aerobic Conditions ◽  
Content Type

ABSTRACTThe bacterial pathogenCampylobacter jejuniis primarily transmitted via the consumption of contaminated foodstuffs, especially poultry meat. In food processing environments,C. jejuniis required to survive a multitude of stresses and requires the use of specific survival mechanisms, such as biofilms. An initial step in biofilm formation is bacterial attachment to a surface. Here, we investigated the effects of a chicken meat exudate (chicken juice) onC. jejunisurface attachment and biofilm formation. Supplementation of brucella broth with ≥5% chicken juice resulted in increased biofilm formation on glass, polystyrene, and stainless steel surfaces with fourC. jejuniisolates and oneC. coliisolate in both microaerobic and aerobic conditions. When incubated with chicken juice,C. jejuniwas both able to grow and form biofilms in static cultures in aerobic conditions. Electron microscopy showed thatC. jejunicells were associated with chicken juice particulates attached to the abiotic surface rather than the surface itself. This suggests that chicken juice contributes toC. jejunibiofilm formation by covering and conditioning the abiotic surface and is a source of nutrients. Chicken juice was able to complement the reduction in biofilm formation of an aflagellated mutant ofC. jejuni, indicating that chicken juice may support food chain transmission of isolates with lowered motility. We provide here a useful model for studying the interaction ofC. jejunibiofilms in food chain-relevant conditions and also show a possible mechanism forC. jejunicell attachment and biofilm initiation on abiotic surfaces within the food chain.

scholarly journals Extracellular DNA Impedes the Transport of Vancomycin in Staphylococcus epidermidis Biofilms Preexposed to Subinhibitory Concentrations of Vancomycin

2014 ◽  
Vol 58 (12) ◽  
pp. 7273-7282 ◽  
Author(s):  
Natalya Doroshenko ◽  
Boo Shan Tseng ◽  
Robert P. Howlin ◽  
Jill Deacon ◽  
Julian A. Wharton ◽  
...  
Keyword(s):  
Confocal Microscopy ◽  
Isothermal Titration Calorimetry ◽  
Staphylococcus Epidermidis ◽  
Binding Constant ◽  
Biofilm Formation ◽  
Potential Role ◽  
Extracellular Dna ◽  
Titration Calorimetry ◽  
Orthopedic Implant ◽  
Content Type

ABSTRACTStaphylococcus epidermidisbiofilm formation is responsible for the persistence of orthopedic implant infections. Previous studies have shown that exposure ofS. epidermidisbiofilms to sub-MICs of antibiotics induced an increased level of biofilm persistence. BODIPY FL-vancomycin (a fluorescent vancomycin conjugate) and confocal microscopy were used to show that the penetration of vancomycin through sub-MIC-vancomycin-treatedS. epidermidisbiofilms was impeded compared to that of control, untreated biofilms. Further experiments showed an increase in the extracellular DNA (eDNA) concentration in biofilms preexposed to sub-MIC vancomycin, suggesting a potential role for eDNA in the hindrance of vancomycin activity. Exogenously added,S. epidermidisDNA increased the planktonic vancomycin MIC and protected biofilm cells from lethal vancomycin concentrations. Finally, isothermal titration calorimetry (ITC) revealed that the binding constant of DNA and vancomycin was 100-fold higher than the previously reported binding constant of vancomycin and its intended cellulard-Ala-d-Ala peptide target. This study provides an explanation of the eDNA-based mechanism of antibiotic tolerance in sub-MIC-vancomycin-treatedS. epidermidisbiofilms, which might be an important factor for the persistence of biofilm infections.

scholarly journals Biofilm regulation in Clostridioides difficile: Novel systems linked to hypervirulence

2021 ◽  
Vol 17 (9) ◽  
pp. e1009817
Author(s):  
Megan G. Taggart ◽  
William J. Snelling ◽  
Patrick J. Naughton ◽  
Roberto M. La Ragione ◽  
James S. G. Dooley ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Gastrointestinal Disease ◽  
Regulatory System ◽  
Disease Recurrence ◽  
The United States ◽  
Extracellular Dna ◽  
Published Data ◽  
Bacterial Cells ◽  
Healthcare Associated Infection ◽  
Clostridioides Difficile

Clostridiodes difficile (C. difficile) was ranked an “urgent threat” by the Centers for Disease Control and Prevention (CDC) in 2019. C. difficile infection (CDI) is the most common healthcare-associated infection (HAI) in the United States of America as well as the leading cause of antibiotic-associated gastrointestinal disease. C. difficile is a gram-positive, rod-shaped, spore-forming, anaerobic bacterium that causes infection of the epithelial lining of the gut. CDI occurs most commonly after disruption of the human gut microflora following the prolonged use of broad-spectrum antibiotics. However, the recurrent nature of this disease has led to the hypothesis that biofilm formation may play a role in its pathogenesis. Biofilms are sessile communities of bacteria protected from extracellular stresses by a matrix of self-produced proteins, polysaccharides, and extracellular DNA. Biofilm regulation in C. difficile is still incompletely understood, and its role in disease recurrence has yet to be fully elucidated. However, many factors have been found to influence biofilm formation in C. difficile, including motility, adhesion, and hydrophobicity of the bacterial cells. Small changes in one of these systems can greatly influence biofilm formation. Therefore, the biofilm regulatory system would need to coordinate all these systems to create optimal biofilm-forming physiology under appropriate environmental conditions. The coordination of these systems is complex and multifactorial, and any analysis must take into consideration the influences of the stress response, quorum sensing (QS), and gene regulation by second messenger molecule cyclic diguanosine monophosphate (c-di-GMP). However, the differences in biofilm-forming ability between C. difficile strains such as 630 and the “hypervirulent” strain, R20291, make it difficult to assign a “one size fits all” mechanism to biofilm regulation in C. difficile. This review seeks to consolidate published data regarding the regulation of C. difficile biofilms in order to identify gaps in knowledge and propose directions for future study.

scholarly journals High Adhesion and Increased Cell Death Contribute to Strong Biofilm Formation in Klebsiella pneumoniae

Pathogens ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 277
Author(s):  
Siddhi Desai ◽  
Kinjal Sanghrajka ◽  
Devarshi Gajjar
Keyword(s):  
Cell Death ◽  
Klebsiella Pneumoniae ◽  
Biofilm Formation ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Extracellular Dna ◽  
Confocal Laser ◽  
Bacterial Cells ◽  
High Adhesion ◽  
Biofilm Matrix

Klebsiella pneumoniae (Kp), is a frequent cause of hospital and community-acquired infections and WHO had declared it as a “priority pathogen”. Biofilm is a major virulence factor of Kp and yet the mechanism of strong biofilm formation in Kp is unclear. A key objective of the present study is to investigate the differences between strong and weak biofilms formed by clinical isolates of Kp on various catheters and in different media conditions and to identify constituents contributing to strong biofilm formation. Quantification of matrix components (extracellular DNA (eDNA), protein, exopolysaccharides (EPS), and bacterial cells), confocal laser scanning microscopy (CLSM), field emission gun scanning electron microscopy (FEG-SEM) and flow-cytometry analysis were performed to compare strong and weak biofilm matrix. Our results suggest increased biofilm formation on latex catheters compared to silicone and silicone-coated latex catheters. Higher amounts of eDNA, protein, EPS, and dead cells were observed in the strong biofilm of Kp. High adhesion capacity and cell death seem to play a major role in formation of strong Kp biofilms. The enhanced eDNA, EPS, and protein in the biofilm matrix appear as a consequence of increased cell death.

scholarly journals Subinhibitory Concentrations of Mupirocin Stimulate Staphylococcus aureus Biofilm Formation by Upregulating cidA

2020 ◽  
Vol 64 (3) ◽  
Author(s):  
Ye Jin ◽  
Yinjuan Guo ◽  
Qing Zhan ◽  
Yongpeng Shang ◽  
Di Qu ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Laser Scanning ◽  
Multidrug Resistant ◽  
Laser Scanning Microscopy ◽  
Extracellular Dna ◽  
Confocal Laser ◽  
Content Type ◽  
Subinhibitory Concentrations ◽  
Biofilm Development

ABSTRACT Previous studies have shown that the administration of antibiotics at subinhibitory concentrations stimulates biofilm formation by the majority of multidrug-resistant Staphylococcus aureus (MRSA) strains. Here, we investigated the effect of subinhibitory concentrations of mupirocin on biofilm formation by the community-associated (CA) mupirocin-sensitive MRSA strain USA300 and the highly mupirocin-resistant clinical S. aureus SA01 to SA05 isolates. We found that mupirocin increased the ability of MRSA cells to attach to surfaces and form biofilms. Confocal laser scanning microscopy (CLSM) demonstrated that mupirocin treatment promoted thicker biofilm formation, which also correlated with the production of extracellular DNA (eDNA). Furthermore, quantitative real-time PCR (RT-qPCR) results revealed that this effect was largely due to the involvement of holin-like and antiholin-like proteins (encoded by the cidA gene), which are responsible for modulating cell death and lysis during biofilm development. We found that cidA expression levels significantly increased by 6.05- to 35.52-fold (P < 0.01) after mupirocin administration. We generated a cidA-deficient mutant of the USA300 S. aureus strain. Exposure of the ΔcidA mutant to mupirocin did not result in thicker biofilm formation than that in the parent strain. We therefore hypothesize that the mupirocin-induced stimulation of S. aureus biofilm formation may involve the upregulation of cidA.

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