scholarly journals Host Peptidic Hormones Affecting Bacterial Biofilm Formation and Virulence

2018 ◽  
Vol 11 (3) ◽  
pp. 227-241 ◽  
Author(s):  
Olivier Lesouhaitier ◽  
Thomas Clamens ◽  
Thibaut Rosay ◽  
Florie Desriac ◽  
Mélissande Louis ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Bacterial Biofilm ◽  
Critical Problem ◽  
Resistant Variant ◽  
Bacterial Physiology ◽  
Gram Positive Bacteria ◽  
Biofilm Production ◽  
The Impact ◽  
Original Approach ◽  
Antibacterial Potential

Bacterial biofilms constitute a critical problem in hospitals, especially in resuscitation units or for immunocompromised patients, since bacteria embedded in their own matrix are not only protected against antibiotics but also develop resistant variant strains. In the last decade, an original approach to prevent biofilm formation has consisted of studying the antibacterial potential of host communication molecules. Thus, some of these compounds have been identified for their ability to modify the biofilm formation of both Gram-negative and Gram-positive bacteria. In addition to their effect on biofilm production, a detailed study of the mechanism of action of these human hormones on bacterial physiology has allowed the identification of new bacterial pathways involved in biofilm formation. In this review, we focus on the impact of neuropeptidic hormones on bacteria, address some future therapeutic issues, and provide a new view of inter-kingdom communication.

scholarly journals Surface Immobilization of Nano-Silver on Polymeric Medical Devices to Prevent Bacterial Biofilm Formation

Pathogens ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 93 ◽  
Author(s):  
Riau ◽  
Aung ◽  
Setiawan ◽  
Yang ◽  
Yam ◽  
...  
Keyword(s):  
Medical Devices ◽  
Biofilm Formation ◽  
Culture Media ◽  
Silver Ions ◽  
Bacterial Biofilm ◽  
Surface Immobilization ◽  
Nano Silver ◽  
Gram Positive Bacteria ◽  
Tissue Microenvironment

: Bacterial biofilm on medical devices is difficult to eradicate. Many have capitalized the anti-infective capability of silver ions (Ag+) by incorporating nano-silver (nAg) in a biodegradable coating, which is then laid on polymeric medical devices. However, such coating can be subjected to premature dissolution, particularly in harsh diseased tissue microenvironment, leading to rapid nAg clearance. It stands to reason that impregnating nAg directly onto the device, at the surface, is a more ideal solution. We tested this concept for a corneal prosthesis by immobilizing nAg and nano-hydroxyapatite (nHAp) on poly(methyl methacrylate), and tested its biocompatibility with human stromal cells and antimicrobial performance against biofilm-forming pathogens, Pseudomonas aeruginosa and Staphylococcus aureus. Three different dual-functionalized substrates—high Ag (referred to as 75:25 HAp:Ag); intermediate Ag (95:5 HAp:Ag); and low Ag (99:1 HAp:Ag) were studied. The 75:25 HAp:Ag was effective in inhibiting biofilm formation, but was cytotoxic. The 95:5 HAp:Ag showed the best selectivity among the three substrates; it prevented biofilm formation of both pathogens and had excellent biocompatibility. The coating was also effective in eliminating non-adherent bacteria in the culture media. However, a 28-day incubation in artificial tear fluid revealed a ~40% reduction in Ag+ release, compared to freshly-coated substrates. The reduction affected the inhibition of S. aureus growth, but not the P. aeruginosa. Our findings suggest that Ag+ released from surface-immobilized nAg diminishes over time and becomes less effective in suppressing biofilm formation of Gram-positive bacteria, such as S. aureus. This advocates the coating, more as a protection against perioperative and early postoperative infections, and less as a long-term preventive solution.

scholarly journals Usnic Acid, a Natural Antimicrobial Agent Able To Inhibit Bacterial Biofilm Formation on Polymer Surfaces

2004 ◽  
Vol 48 (11) ◽  
pp. 4360-4365 ◽  
Author(s):  
I. Francolini ◽  
P. Norris ◽  
A. Piozzi ◽  
G. Donelli ◽  
P. Stoodley
Keyword(s):  
Biofilm Formation ◽  
Usnic Acid ◽  
Modern Medicine ◽  
The Body ◽  
Bacterial Biofilm ◽  
Polymer Surfaces ◽  
Gram Positive Bacteria ◽  
The Status ◽  
Bacteria And Fungi ◽  
Systemic Infections

ABSTRACT In modern medicine, artificial devices are used for repair or replacement of damaged parts of the body, delivery of drugs, and monitoring the status of critically ill patients. However, artificial surfaces are often susceptible to colonization by bacteria and fungi. Once microorganisms have adhered to the surface, they can form biofilms, resulting in highly resistant local or systemic infections. At this time, the evidence suggests that (+)-usnic acid, a secondary lichen metabolite, possesses antimicrobial activity against a number of planktonic gram-positive bacteria, including Staphylococcus aureus, Enterococcus faecalis, and Enterococcus faecium. Since lichens are surface-attached communities that produce antibiotics, including usnic acid, to protect themselves from colonization by other bacteria, we hypothesized that the mode of action of usnic acid may be utilized in the control of medical biofilms. We loaded (+)-usnic acid into modified polyurethane and quantitatively assessed the capacity of (+)-usnic acid to control biofilm formation by either S. aureus or Pseudomonas aeruginosa under laminar flow conditions by using image analysis. (+)-Usnic acid-loaded polymers did not inhibit the initial attachment of S. aureus cells, but killing the attached cells resulted in the inhibition of biofilm. Interestingly, although P. aeruginosa biofilms did form on the surface of (+)-usnic acid-loaded polymer, the morphology of the biofilm was altered, possibly indicating that (+)-usnic acid interfered with signaling pathways.

scholarly journals Impact of Bacterial Biofilm Formation on In Vitro and In Vivo Activities of Antibiotics

1998 ◽  
Vol 42 (4) ◽  
pp. 895-898 ◽  
Author(s):  
Silvia Schwank ◽  
Zarko Rajacic ◽  
Werner Zimmerli ◽  
Jürg Blaser
Keyword(s):  
Animal Model ◽  
Staphylococcus Epidermidis ◽  
Biofilm Formation ◽  
Bacterial Biofilm ◽  
Phenotypic Resistance ◽  
Vitro Model ◽  
The Impact ◽  
Isogenic Strains

ABSTRACT The impact of bacterial adherence on antibiotic activity was analyzed with two isogenic strains of Staphylococcus epidermidis that differ in the features of their in vitro biofilm formation. The eradication of bacteria adhering to glass beads by amikacin, levofloxacin, rifampin, or teicoplanin was studied in an animal model and in a pharmacokinetically matched in vitro model. The features of S. epidermidis RP62A that allowed it to grow on surfaces in multiple layers promoted phenotypic resistance to antibiotic treatment, whereas strain M7 failed to accumulate, despite initial adherence on surfaces and growth in suspension similar to those for RP62A. Biofilms of S. epidermidis M7 were better eradicated than those of strain RP62A in vitro (46 versus 31%;P < 0.05) as well as in the animal model (39 versus 9%; P < 0.01).

scholarly journals purL gene expression affects biofilm formation and symbiotic persistence of Photorhabdus temperata in the nematode Heterorhabditis bacteriophora

Microbiology ◽  
2011 ◽  
Vol 157 (9) ◽  
pp. 2595-2603 ◽  
Author(s):  
Ruisheng An ◽  
Parwinder S. Grewal
Keyword(s):  
Gene Expression ◽  
Metabolic Pathway ◽  
Biofilm Formation ◽  
Heterorhabditis Bacteriophora ◽  
Bacterial Biofilm ◽  
Infective Juvenile ◽  
Plant Interactions ◽  
Symbiotic Interaction ◽  
The Impact ◽  
Photorhabdus Temperata

Extensive studies of the well-known legume and rhizobium symbiosis model system suggest that the purine metabolic pathway plays a key role in microbe–plant interactions, although the exact mechanism is unknown. Here, we report the impact of a key purine metabolic gene, purL, on the symbiotic interaction between the bacterium Photorhabdus temperata and its nematode partner Heterorhabditis bacteriophora. Real-time PCR assays showed that the purL gene was upregulated in P. temperata in the nematode infective juvenile compared with artificial media. Mutation of the purL gene by in-frame deletion dramatically decreased the capacity of the bacterium to persist in infective juveniles and its ability to form biofilm in vitro. It was further demonstrated that purL gene expression was positively related to bacterial biofilm formation and the symbiotic persistence of the bacterium in nematode infective juveniles. A ΔpurL mutant lost the ability to support infective juvenile formation in the media which weakly supported biofilm formation, suggesting that a critical level of biofilm formation is required by the bacteria to support infective juvenile formation and thus establish their partnership. In addition, the defects in both biofilm formation and symbiotic ability due to the disruption of the purL gene could be partially restored by the addition of 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR), an intermediate of the purine biosynthesis pathway. Overall, these data indicate that the purine metabolic pathway is important in microbe–animal symbioses, and that it may influence symbiotic interactions at the level of biofilm formation.

scholarly journals Disrupting Irreversible Bacterial Adhesion and Biofilm Formation with an Engineered Enzyme

2021 ◽  
Author(s):  
Holly M. Mayton ◽  
Sharon L. Walker ◽  
Bryan W. Berger
Keyword(s):  
Listeria Monocytogenes ◽  
Bacterial Adhesion ◽  
Biofilm Formation ◽  
Glycosyl Hydrolase ◽  
Cell Surface Hydrophobicity ◽  
Bacterial Biofilm ◽  
Enzyme Treatment ◽  
E Coli ◽  
Initial Adhesion ◽  
The Impact

Biofilm formation is often attributed to post-harvest bacteria persistence on fresh produce and food handling surfaces. In this study, a predicted glycosyl hydrolase enzyme was expressed, purified and validated for removal of microbial biofilms from biotic and abiotic surfaces under conditions used for chemical cleaning agents. Crystal violet biofilm staining assays revealed that 0.1 mg/mL of enzyme inhibited up to 41% of biofilm formation by E. coli O157:H7, E. coli 25922, Salmonella Typhimurium, and Listeria monocytogenes. Further, the enzyme was effective at removing mature biofilms, providing a 35% improvement over rinsing with a saline solution alone. Additionally, a parallel-plate flow cell was used to directly observe and quantify the impact of enzyme rinses on E. coli O157:H7 cells adhered to spinach leaf surfaces. The presence of 1 mg/L enzyme resulted in nearly 6 times greater detachment rate coefficients than a DI water rinse, while the total cells removed from the surface increased from 10% to 25% over the 30 minute rinse time, reversing the initial phases of biofilm formation. Enzyme treatment of all 4 cell types resulted in significantly reduced cell surface hydrophobicity, and collapse of negatively stained E. coli 25922 cells imaged by electron microscopy, suggesting potential polysaccharide surface modification of enzyme-treated bacteria. Collectively, these results point to the broad substrate specificity and robustness of the enzyme to different types of biofilm stages, solution conditions and pathogen biofilm types, and may be useful as a method for removal or inhibition of bacterial biofilm formation. IMPORTANCE In this study, the ability of an engineered enzyme to reduce bacterial adhesion and biofilm formation of several foodborne pathogens was demonstrated, representing a promising option for enhancing or replacing chlorine and other chemical sanitizers in food processing applications. Specifically, significant reductions of the pathogens Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes biofilms are observed, as well as reduction in initial adhesion. Enzymes have the added benefits of being green, sustainable alternatives to chemical sanitizers, as well as having minimal impact on food properties, in contrast with many alternative antimicrobial options such as bleach that aim to minimize food safety risks.

scholarly journals In-Vitro Evaluation of Biological Activity of New Series of 1, 3, 4-Oxadiazole Derivatives Against Bap Gene Expression in Acinetobacter bumanni Biofilm

2021 ◽  
Vol In Press (In Press) ◽  
Author(s):  
Sedigheh Akbarnezhad Ghareh Lar ◽  
Nakisa Zarrabi Ahrabi ◽  
Yasin SarveAhrabi
Keyword(s):  
Biofilm Formation ◽  
Functional Group ◽  
Biological Activities ◽  
Antimicrobial Properties ◽  
Housekeeping Gene ◽  
Bacterial Biofilm ◽  
Wide Range ◽  
Oxadiazole Derivatives ◽  
The Impact

Background: Acinetobacter bumanni is one of the most common opportunistic pathogens in health centers that is resistant to many antibiotics due to biofilm production. 1, 3, 4-oxadiazoles have a wide range of biological activities. Objectives: The aim of this research was to examine the impact of new 1, 3, 4-oxadiazole derivatives on the expression of biofilm-associated surface protein (Bap), playing an important role in promoting the biofilm formation ability of A. baumannii strains. Methods: Derivatives of 1, 3, 4-oxadiazole were synthesized through a one-step synthesis. A. baumannii strains were identified and isolated in the laboratory. The antimicrobial properties of the synthesized materials against the isolated strains were investigated. DNA, RNA, and cDNA were extracted, and the relative expression of BAP gene in A. baumannii isolates was evaluated by real-time polymerase chain reaction. Results: The compound with methoxyphenyl functional group with MIC = 62.50 mg/mL had the best inhibitory performance among all derivatives. Also, the combination of 4i reduced the expression of the Bap gene by about 24 times, but it had no effect on the expression of the 16srRNA housekeeping gene. Conclusions: 1, 3, 4-oxadiazole derivatives, especially the methoxyphenyl functional group, act as an inhibitor of bacterial biofilm formation and have the potential to be used in the pharmaceutical and biological industries.

scholarly journals In Vitro and In Silico Evaluation of Biological Activity of a New Series of Oxadiazole Compounds Against Esp Gene Expression in Enterococcus faecalis Biofilm

2021 ◽  
Vol In Press (In Press) ◽  
Author(s):  
Sepideh Ghameshlouei ◽  
Nakisa Zarrabi Ahrabi ◽  
Yasin SarveAhrabi
Keyword(s):  
Enterococcus Faecalis ◽  
Biofilm Formation ◽  
Biological Activities ◽  
Control Sample ◽  
Surface Protein ◽  
Bacterial Biofilm ◽  
Receptor Binding Site ◽  
Wide Range ◽  
Oxadiazole Derivatives ◽  
The Impact

Background: The enterococcal surface protein (Esp) is a high-molecular-weight surface protein of biofilm creating agent in Enterococcus faecalis. Oxadiazoles have a wide range of biological activities. Objective: This research aimed to examine the impact of new oxadiazole derivatives on the expression of Esp, playing an important role in promoting the biofilm formation ability of drug-resistant E. faecalis strains. Method: 1, 3, 4-oxadiazole derivatives were synthesized through a one-step synthesis. E. faecalis strains were collected and isolated from hospitals in Tehran. The antimicrobial properties of the synthesized materials against the isolated strains were investigated. RNA, DNA, and cDNA were extracted, and the relative expression of Esp in E. faecalis isolates was evaluated by real-time PCR. Docking study was performed by AutoDock vina software, and the resulting docking poses were analyzed using Discovery Studio 4.5 Client software. Results: The use of synthesized derivatives changed the Esp expression level in different isolates compared to the control sample. The two compounds containing naphthalene (4f) and methoxyphenyl (4g) caused respectively a 2-fold and a 3-fold decrease in Esp expression compared to the control sample. The compound 4f with the best binding energy among the compounds (-9.2) had the most hydrogen and hydrophobic bonds with the receptor-binding site. Conclusions: 1, 3, 4-oxadiazole derivatives, especially naphthalene and methoxyphenyl, act as inhibitors of bacterial biofilm formation and can be used in the pharmaceutical and biological industries.

scholarly journals Protozoan impact on bacterial biofilm formation

2010 ◽  
Vol 47 (1) ◽  
pp. 3-10 ◽  
Author(s):  
Krzysztof Rychert ◽  
Thomas Neu
Keyword(s):  
Activated Sludge ◽  
Biofilm Formation ◽  
Laser Scanning ◽  
Grazing Pressure ◽  
Bacterial Biofilm ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Protozoan Community ◽  
Biofilm Development ◽  
The Impact

Protozoan impact on bacterial biofilm formationConfocal laser scanning microscopy in combination with digital image analysis was used to assess the impact of protozoa on bacterial colonisation of surfaces. Bacterial biofilms were developed from activated sludge in microscope flow cells and were exposed to the grazing pressure of protozoa. The protozoan community from healthy activated sludge and a culture of flagellateBodo saltanswere used as grazers. Experiments comprised 48-h incubations in 3 treatment variants: bacteria with protozoa, bacteria with protozoa added after some time and bacteria without protozoa. When necessary, the elimination of protozoa from the inoculum was carried out with cycloheximide and NiSO4. Experiments demonstrated that protozoa from healthy activated sludge initially disturbed the biofilm development but later they could stimulate its growth. Similar results could be established in the experiment withBodo saltans(inoculum: 1000 cells/ml), however differences were not statistically significant. The finding that protozoa support biofilm development during specific stages may be relevant for biofilm studies with mixed environmental biofilm communities.

Plant components affect bacterial biofilm development by altering their cell surface physicochemical properties: a predictability study using Actinomyces naeslundii

2020 ◽  
Author(s):  
Yi Wang ◽  
Lakshman P Samaranayake ◽  
Gary A Dykes
Keyword(s):  
Cell Surface ◽  
Physicochemical Properties ◽  
Biofilm Formation ◽  
Cell Surface Hydrophobicity ◽  
Surface Hydrophobicity ◽  
Bacterial Biofilm ◽  
Actinomyces Naeslundii ◽  
Surface Physicochemical Properties ◽  
Biofilm Development ◽  
The Impact

Abstract We hypothesized that the initial events leading to biofilm formation by bacteria, in general, are predominantly mediated by cell surface physicochemical interactions, and that natural products can impact the process by altering cell surface physicochemical properties. We exemplified this phenomenon using Actinomyces naeslundii as the model organism, and using tea products to modify its cell surface physicochemical properties. To test the hypothesis, a non-linear multiple regression model incorporating a normal distribution curve was constructed to explain the impact of tea extracts on the physiochemical processes of biofilm formation by A. naeslundii. The model utilized tea extract-induced changes in cell surface physicochemical properties as independent variables, and the corresponding biofilm formation as a dependent variable. Five different tea extracts were used to treat A. naeslundii, and their impact on the cell surface hydrophobicity, charge, auto-aggregation, attachment and biofilm formation on four different hard surfaces were measured and the data were used to construct the model. The established model was then tested in independent experiments involving other plant extracts and purified phytochemicals. Experimental results showed that the tea extracts significantly reduced cell surface hydrophobicity (by up to 21.3%), increased cell surface charge and auto-aggregation (by up to 4.5 mV and 14.9%, respectively), inhibited attachment (by 0.6–2.5 log CFU cm−2) and affected biofilm formation (by up to 0.6 log CFU cm−2). The model indicated that both cell surface hydrophobicity and charge played an important role in bacterial auto-aggregation and attachment, and that the latter two phenomena significantly correlated with subsequent biofilm development. The accuracy of the model construct was approximately 64%. This modelling approach can be employed for other microbial colonization systems to predict biofilm formation, and to study the impact of cell surface physicochemical properties in biofilm development.

scholarly journals Analysis of the bacterial biofilm formation in different models of the in vitro culture

2021 ◽  
Vol 19 (1) ◽  
pp. 40-45
Author(s):  
Agnieszka Bogut ◽  
◽  
Agnieszka Magryś ◽  
Keyword(s):  
Biofilm Formation ◽  
Culture Media ◽  
Microtiter Plate ◽  
Bacterial Biofilm ◽  
Atmospheric Conditions ◽  
Experimental Conditions ◽  
Microtiter Plate Assay ◽  
Biofilm Production ◽  
Strain Type

Introduction. Microtiter plate assay (MPA) remains one of workhorses of in vitro biofilm research but it requires optimization of experimental conditions to fulfill the biofilm formation requirements of different bacterial pathogens. Aim. The aim was to determine the effect of TSB and RPMI1640 culture media and selected culture variables (O2 vs. 5% CO2, extended incubation time) on the biofilm production by bacteria commonly involved in biofilm-related infections: Enterococcus faecalis (EF), Escherichia coli (EC), Staphylococcus aureus (SA), Pseudomonas aeruginosa (PA), Klebsiella pneumoniae (KP). Material and methods. The investigation was performed using the MPA with crystal violet. Results. Statistically significant (p<0.05) increase in biofilm production between 24h and 72h time points was observed for EF (TSB o2, RPMIo2 and RPMIco2), EC (TSBo2), SA (TSBo2, TSBco2), KP (TSBo2, TSBco2), PA (RPMIco2, TSBco2). The TSB caused a significantly greater stimulation of biofilm production compared to RPM1640. It outcompeted RPMI1640 irrespective of the atmospheric conditions for SA and KP and under aerobic conditions for EF. Conclusion. Although the TSB provided the most optimal conditions for biofilm production, the process was influenced by the strain type, atmospheric conditions and period of cultivation which limits the ability to design a single universal model of the in vitro biofilm investigation.

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