Iron-binding compounds impair Pseudomonas aeruginosa biofilm formation, especially under anaerobic conditions

2009 ◽  
Vol 58 (6) ◽  
pp. 765-773 ◽  
Author(s):  
Che Y. O'May ◽  
Kevin Sanderson ◽  
Louise F. Roddam ◽  
Sylvia M. Kirov ◽  
David W. Reid
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Low Oxygen ◽  
Anaerobic Conditions ◽  
Chronic Infections ◽  
Strain Pao1 ◽  
Biofilm Inhibition ◽  
Oxygen Conditions ◽  
Biofilm Development ◽  
Chelating Compounds

The success of Pseudomonas aeruginosa in cystic fibrosis (CF) and other chronic infections is largely attributed to its ability to grow in antibiotic-resistant biofilm communities. This study investigated the effects of limiting iron levels as a strategy for preventing/disrupting P. aeruginosa biofilms. A range of synthetic and naturally occurring iron-chelating agents were examined. Biofilm development by P. aeruginosa strain PAO1 and CF sputum isolates from chronically infected individuals was significantly decreased by iron removal under aerobic atmospheres. CF strains formed poor biofilms under anaerobic conditions. Strain PAO1 was also tested under anaerobic conditions. Biofilm formation by this model strain was almost totally prevented by several of the chelators tested. The ability of synthetic chelators to impair biofilm formation could be reversed by iron addition to cultures, providing evidence that these effective chelating compounds functioned by directly reducing availability of iron to P. aeruginosa. In contrast, the biological chelator lactoferrin demonstrated enhanced anti-biofilm effects as iron supplementation increased. Hence biofilm inhibition by lactoferrin appeared to occur through more complex mechanisms to those of the synthetic chelators. Overall, our results demonstrate the importance of iron availability to biofilms and that iron chelators have potential as adjunct therapies for preventing biofilm development, especially under low oxygen conditions such as encountered in the chronically infected CF lung.

scholarly journals Modulation of Pseudomonas aeruginosa Biofilm Dispersal by a Cyclic-Di-GMP Phosphodiesterase with a Putative Hypoxia-Sensing Domain

2010 ◽  
Vol 76 (24) ◽  
pp. 8160-8173 ◽  
Author(s):  
Shuwen An ◽  
Ji'en Wu ◽  
Lian-Hui Zhang
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Regulatory Protein ◽  
Phosphodiesterase Activity ◽  
Low Oxygen ◽  
Ggdef Domain ◽  
Biofilm Dispersal ◽  
Biofilm Development

ABSTRACT Pseudomonas aeruginosa encodes many enzymes that are potentially associated with the synthesis or degradation of the widely conserved second messenger cyclic-di-GMP (c-di-GMP). In this study, we show that mutation of rbdA, which encodes a fusion protein consisting of PAS-PAC-GGDEF-EAL multidomains, results in decreased biofilm dispersal. RbdA contains a highly conserved GGDEF domain and EAL domain, which are involved in the synthesis and degradation of c-di-GMP, respectively. However, in vivo and in vitro analyses show that the full-length RbdA protein only displays phosphodiesterase activity, causing c-di-GMP degradation. Further analysis reveals that the GGDEF domain of RbdA plays a role in activating the phosphodiesterase activity of the EAL domain in the presence of GTP. Moreover, we show that deletion of the PAS domain or substitution of the key residues implicated in sensing low-oxygen stress abrogates the functionality of RbdA. Subsequent study showed that RbdA is involved in positive regulation of bacterial motility and production of rhamnolipids, which are associated with biofilm dispersal, and in negative regulation of production of exopolysaccharides, which are required for biofilm formation. These data indicate that the c-di-GMP-degrading regulatory protein RbdA promotes biofilm dispersal through its two-pronged effects on biofilm development, i.e., downregulating biofilm formation and upregulating production of the factors associated with biofilm dispersal.

scholarly journals Effect of chitosan nanoparticles on quorum sensing-controlled virulence factors and expression of LasI and RhlI genes among Pseudomonas aeruginosa clinical isolates

2021 ◽  
Vol 7 (4) ◽  
pp. 415-430
Author(s):  
Rana Abdel Fattah Abdel Fattah ◽  
◽  
Fatma El zaharaa Youssef Fathy ◽  
Tahany Abdel Hamed Mohamed ◽  
Marwa Shabban Elsayed
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Virulence Factors ◽  
Biofilm Formation ◽  
Chitosan Nanoparticles ◽  
Inhibitory Effect ◽  
Biofilm Inhibition ◽  
Expression Levels ◽  
The Mean ◽  
Biofilm Development

<abstract> <p>Antibiotic-resistant strains of <italic>Pseudomonas aeruginosa (P. aeruginosa</italic>) pose a major threat for healthcare-associated and community-acquired infections. <italic>P. aeruginosa</italic> is recognized as an opportunistic pathogen using quorum sensing (QS) system to regulate the expression of virulence factors and biofilm development. Thus, meddling with the QS system would give alternate methods of controlling the pathogenicity. This study aimed to assess the inhibitory impact of chitosan nanoparticles (CS-NPs) on <italic>P. aeruginosa</italic> virulence factors regulated by QS (e.g., motility and biofilm formation) and <italic>LasI</italic> and <italic>RhlI</italic> gene expression. Minimum inhibitory concentration (MIC) of CS-NPs against 30 isolates of <italic>P. aeruginosa</italic> was determined. The CS-NPs at sub-MIC were utilized to assess their inhibitory effect on motility, biofilm formation, and the expression levels of <italic>LasI</italic> and <italic>RhlI</italic> genes. CS-NPs remarkably inhibited the tested virulence factors as compared to the controls grown without the nanoparticles. The mean (±SD) diameter of swimming motility was decreased from 3.93 (±1.5) to 1.63 (±1.02) cm, and the mean of the swarming motility was reduced from 3.5 (±1.6) to 1.9 (±1.07) cm. All isolates became non-biofilm producers, and the mean percentage rate of biofilm inhibition was 84.95% (±6.18). Quantitative real-time PCR affirmed the opposition of QS activity by lowering the expression levels of <italic>LasI</italic> and <italic>RhlI</italic> genes; the expression level was decreased by 90- and 100-folds, respectively. In conclusion, the application of CS-NPs reduces the virulence factors significantly at both genotypic and phenotypic levels. These promising results can breathe hope in the fight against resistant <italic>P. aeruginosa</italic> by repressing its QS-regulated virulence factors.</p> </abstract>

scholarly journals Antibiofilm activity of aminopropanol derivatives against Pseudomonas aeruginosa

2018 ◽  
pp. 93-100
Author(s):  
D. M. Dudikova ◽  
Z. S. Suvorova ◽  
V. V. Nedashkivska ◽  
A. O. Sharova ◽  
M. L. Dronova ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Antimicrobial Agents ◽  
Bacterial Biofilm ◽  
Antibiofilm Activity ◽  
Dependent Manner ◽  
Inhibition Activity ◽  
Chronic Infections ◽  
High Concentration ◽  
Biofilm Inhibition

Bacterial biofilm, particularly formed by Pseudomonas aeruginosa, are a cause of severe chronic infectious diseases. Bacteria within a biofilm are phenotypically more resistant to antibiotics and the macroorganism immune system, making it an important virulence factor for many microbes. The aminopropanol derivatives with adamantyl (KVM-97) and N-alkylaryl radicals (KVM-194, KVM-204, KVM-261, and KVM-262) were used as study object. The aim of this study was to investigate the antibiofilm activity of compounds on biofilm formation and on mature biofilm of P. aeruginosa. The effects of the aminopropanol derivatives on the biofilm mass were evaluated by using crystal violet assay. Ciprofloxacin, meropenem, ceftazidime, gentamicin were used as reference substances. Reported results demonstrate that all compounds displayed antibiofilm activity at the tested concentrations. Remarkable reduction in biofilm formation of P. aeruginosa was found after treatment with KVM-97, KVM-261 and KVM-262 in high concentration (5× MIC), biofilm inhibition activity were 84.3%, 90.5% and 83.3% respectively. After a treatment with KVM-204 at 250 μg/ml (5× MIC) 76.6% of the preformed 24-hr biofilms were destroyed. Furthermore, compounds KVM-97, KVM-194, and KVM-261 in both concentrations showed potent antibiofilm activity against the P. aeruginosa, inhibition activity values being between 56.7 and 65.7%. All tested compounds in dose-dependent manner exhibited pronounced inhibition activity against mature 5-days P. аeruginosa biofilm. It was also observed that tested compounds show high antibiofilm activity in comparison to reference antimicrobials. The aminopropanol derivatives may provide templates for a new group of antimicrobial agents and potential future therapeutics for treating chronic infections.

scholarly journals High-Throughput Screens for Small-Molecule Inhibitors of Pseudomonas aeruginosa Biofilm Development

2007 ◽  
Vol 51 (10) ◽  
pp. 3582-3590 ◽  
Author(s):  
Lauren M. Junker ◽  
Jon Clardy
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Small Molecule ◽  
High Throughput ◽  
Biofilm Formation ◽  
Small Molecule Inhibitors ◽  
Opportunistic Pathogen ◽  
Positive Control ◽  
Strain Pao1 ◽  
Small Molecule Modulators ◽  
Biofilm Development

ABSTRACT Pseudomonas aeruginosa is both a model biofilm-forming organism and an opportunistic pathogen responsible for chronic lung infections in cystic fibrosis (CF) patients and infections in burn patients, among other maladies. Here we describe the development of an efficient high-throughput screen to identify small-molecule modulators of biofilm formation. This screen has been run with 66,095 compounds to identify those that prevent biofilm formation without affecting planktonic bacterial growth. The screen is a luminescence-based attachment assay that has been validated with several strains of P. aeruginosa and compared to a well-established but low-throughput crystal violet staining biofilm assay. P. aeruginosa strain PAO1 was selected for use in the screen both because it forms robust biofilms and because genetic information and tools are available for the organism. The attachment-inhibited mutant, strain PAO1 ΔfliC, was used as a screening-positive control. We have also developed and validated a complementary biofilm detachment assay that can be used as an alternative primary screen or secondary screen for the attachment screening-positive compounds. We have determined the potencies of 61 compounds against biofilm attachment and have identified 30 compounds that fall into different structural classes as biofilm attachment inhibitors with 50% effective concentrations of less than 20 μM. These small-molecule inhibitors could lead to the identification of their relevant biofilm targets or potential therapeutics for P. aeruginosa infections.

scholarly journals Sodium Salicylate Influences the Pseudomonas aeruginosa Biofilm Structure and Susceptibility Towards Silver

2021 ◽  
Vol 22 (3) ◽  
pp. 1060
Author(s):  
Erik Gerner ◽  
Sofia Almqvist ◽  
Peter Thomsen ◽  
Maria Werthén ◽  
Margarita Trobos
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Sodium Salicylate ◽  
Treatment Strategies ◽  
Cell Aggregation ◽  
Wound Fluid ◽  
Global Challenge ◽  
3D Collagen ◽  
Biofilm Development ◽  
Biofilm Structure

Hard-to-heal wounds are typically infected with biofilm-producing microorganisms, such as Pseudomonas aeruginosa, which strongly contribute to delayed healing. Due to the global challenge of antimicrobial resistance, alternative treatment strategies are needed. Here, we investigated whether inhibition of quorum sensing (QS) by sodium salicylate in different P. aeruginosa strains (QS-competent, QS-mutant, and chronic wound strains) influences biofilm formation and tolerance to silver. Biofilm formation was evaluated in simulated serum-containing wound fluid in the presence or absence of sodium salicylate (NaSa). Biofilms were established using a 3D collagen-based biofilm model, collagen coated glass, and the Calgary biofilm device. Furthermore, the susceptibility of 48-h-old biofilms formed by laboratory and clinical strains in the presence or absence of NaSa towards silver was evaluated by assessing cell viability. Biofilms formed in the presence of NaSa were more susceptible to silver and contained reduced levels of virulence factors associated with biofilm development than those formed in the absence of NaSa. Biofilm aggregates formed by the wild-type but not the QS mutant strain, were smaller and less heterogenous in size when grown in cultures with NaSa compared to control. These data suggest that NaSa, via a reduction of cell aggregation in biofilms, allows the antiseptic to become more readily available to cells.

scholarly journals Identification and Functional Analysis of ThADH1 and ThADH4 Genes Involved in Tolerance to Waterlogging Stress in Taxodium hybrid ‘Zhongshanshan 406’

Genes ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 225
Author(s):  
Lei Xuan ◽  
Jianfeng Hua ◽  
Fan Zhang ◽  
Zhiquan Wang ◽  
Xiaoxiao Pei ◽  
...  
Keyword(s):  
Ethanol Metabolism ◽  
Flooding Tolerance ◽  
Transcriptome Data ◽  
Low Oxygen ◽  
Anaerobic Conditions ◽  
Waterlogging Tolerance ◽  
Waterlogging Stress ◽  
Adh Genes ◽  
Oxygen Conditions ◽  
Stems And Leaves

The Taxodium hybrid ‘Zhongshanshan 406’ (T. hybrid ‘Zhongshanshan 406’) [Taxodium mucronatum Tenore × Taxodium distichum (L.). Rich] has an outstanding advantage in flooding tolerance and thus has been widely used in wetland afforestation in China. Alcohol dehydrogenase genes (ADHs) played key roles in ethanol metabolism to maintain energy supply for plants in low-oxygen conditions. Two ADH genes were isolated and characterized—ThADH1 and ThADH4 (GenBank ID: AWL83216 and AWL83217—basing on the transcriptome data of T. hybrid ‘Zhongshanshan 406’ grown under waterlogging stress. Then the functions of these two genes were investigated through transient expression and overexpression. The results showed that the ThADH1 and ThADH4 proteins both fall under ADH III subfamily. ThADH1 was localized in the cytoplasm and nucleus, whereas ThADH4 was only localized in the cytoplasm. The expression of the two genes was stimulated by waterlogging and the expression level in roots was significantly higher than those in stems and leaves. The respective overexpression of ThADH1 and ThADH4 in Populus caused the opposite phenotype, while waterlogging tolerance of the two transgenic Populus significantly improved. Collectively, these results indicated that genes ThADH1 and ThADH4 were involved in the tolerance and adaptation to anaerobic conditions in T. hybrid ‘Zhongshanshan 406’.

scholarly journals Pseudomonas aeruginosa las and rhl quorum-sensing systems are important for infection and inflammation in a rat prostatitis model

Microbiology ◽  
2009 ◽  
Vol 155 (8) ◽  
pp. 2612-2619 ◽  
Author(s):  
Lisa K. Nelson ◽  
Genevieve H. D'Amours ◽  
Kimberley M. Sproule-Willoughby ◽  
Douglas W. Morck ◽  
Howard Ceri
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Tissue Damage ◽  
Inflammatory Markers ◽  
Bacterial Colonization ◽  
Opportunistic Pathogen ◽  
Infection Model ◽  
Chronic Infections ◽  
Strain Pao1 ◽  
Rat Prostate

Pseudomonas aeruginosa frequently acts as an opportunistic pathogen of mucosal surfaces; yet, despite causing aggressive prostatitis in some men, its role as a pathogen in the prostate has not been investigated. Consequently, we developed a Ps. aeruginosa infection model in the rat prostate by instilling wild-type (WT) Ps. aeruginosa strain PAO1 into the rat prostate. It was found that Ps. aeruginosa produced acute and chronic infections in this mucosal tissue as determined by bacterial colonization, gross morphology, tissue damage and inflammatory markers. WT strain PAO1 and its isogenic mutant PAO-JP2, in which both the lasI and rhlI quorum-sensing signal systems have been silenced, were compared during both acute and chronic prostate infections. In acute infections, bacterial numbers and inflammatory markers were comparable between WT PA01 and PAO-JP2; however, considerably less tissue damage occurred in infections with PAO-JP2. Chronic infections with PAO-JP2 resulted in reduced bacterial colonization, tissue damage and inflammation as compared to WT PAO1 infections. Therefore, the quorum-sensing lasI and rhlI genes in Ps. aeruginosa affect acute prostate infections, but play a considerably more important role in maintaining chronic infections. We have thus developed a highly reproducible model for the study of Ps. aeruginosa virulence in the prostate.

Putrescine and its metabolic precursor arginine promote biofilm and c-di-GMP synthesis in Pseudomonas aeruginosa

2021 ◽  
Author(s):  
Zhexian Liu ◽  
Sarzana S. Hossain ◽  
Zayda Morales Moreira ◽  
Cara H. Haney
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Immune Responses ◽  
Biofilm Formation ◽  
Antimicrobial Agents ◽  
Bacterial Pathogen ◽  
Guanosine Monophosphate ◽  
Genetic Approach ◽  
Chronic Infections ◽  
Host Immune Responses ◽  
Primary Mechanism

Pseudomonas aeruginosa , an opportunistic bacterial pathogen can synthesize and catabolize a number of small cationic molecules known as polyamines. In several clades of bacteria polyamines regulate biofilm formation, a lifestyle-switching process that confers resistance to environmental stress. The polyamine putrescine and its biosynthetic precursors, L-arginine and agmatine, promote biofilm formation in Pseudomonas spp. However, it remains unclear whether the effect is a direct effect of polyamines or through a metabolic derivative. Here we used a genetic approach to demonstrate that putrescine accumulation, either through disruption of the spermidine biosynthesis pathway or the catabolic putrescine aminotransferase pathway, promoted biofilm formation in P. aeruginosa . Consistent with this observation, exogenous putrescine robustly induced biofilm formation in P. aeruginosa that was dependent on putrescine uptake and biosynthesis pathways. Additionally, we show that L-arginine, the biosynthetic precursor of putrescine, also promoted biofilm formation, but via a mechanism independent of putrescine or agmatine conversion. We found that both putrescine and L-arginine induced a significant increase in the intracellular level of bis-(3′-5′)-cyclic dimeric guanosine monophosphate (c-di-GMP) (c-di-GMP), a bacterial second messenger widely found in Proteobacteria that upregulates biofilm formation. Collectively these data show that putrescine and its metabolic precursor arginine promote biofilm and c-di-GMP synthesis in P. aeruginosa . Importance: Biofilm formation allows bacteria to physically attach to a surface, confers tolerance to antimicrobial agents, and promotes resistance to host immune responses. As a result, regulation of biofilm is often crucial for bacterial pathogens to establish chronic infections. A primary mechanism of biofilm promotion in bacteria is the molecule c-di-GMP, which promotes biofilm formation. The level of c-di-GMP is tightly regulated by bacterial enzymes. In this study, we found that putrescine, a small molecule ubiquitously found in eukaryotic cells, robustly enhances P. aeruginosa biofilm and c-di-GMP. We propose that P. aeruginosa may sense putrescine as a host-associated signal that triggers a lifestyle switching that favors chronic infection.

scholarly journals Green Tea Polyphenols and Padma Hepaten Inhibit Candida albicans Biofilm Formation

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Yosi Farkash ◽  
Mark Feldman ◽  
Isaac Ginsburg ◽  
Doron Steinberg ◽  
Miriam Shalish
Keyword(s):  
Candida Albicans ◽  
Green Tea ◽  
Crystal Violet ◽  
Biofilm Formation ◽  
Host Cells ◽  
Green Tea Polyphenols ◽  
Crystal Violet Staining ◽  
Biofilm Inhibition ◽  
Therapeutic Concept ◽  
Biofilm Development

Candida albicans (C. albicans) is the most prevalent opportunistic human pathogenic fungus and can cause mucosal membrane infections and invade the blood. In the oral cavity, it can ferment dietary sugars, produce organic acids and therefore has a role in caries development. In this study, we examined whether the polyphenol rich extractions Polyphenon from green tea (PPFGT) and Padma Hepaten (PH) can inhibit the caries-inducing properties of C. albicans. Biofilms of C. albicans were grown in the presence of PPFGT and PH. Formation of biofilms was tested spectrophotometrically after crystal violet staining. Exopolysaccharides (EPS) secretion was quantified using confocal scanning laser microscopy (CSLM). Treated C. albicans morphology was demonstrated using scanning electron microscopy (SEM). Expression of virulence-related genes was tested using qRT-PCR. Development of biofilm was also tested on an orthodontic surface (Essix) to assess biofilm inhibition ability on such appliances. Both PPFGT and PH dose-dependently inhibited biofilm formation, with no inhibition on planktonic growth. The strongest inhibition was obtained using the combination of the substances. Crystal violet staining showed a significant reduction of 45% in biofilm formation using a concentration of 2.5mg/ml PPFGT and 0.16mg/ml PH. A concentration of 1.25 mg/ml PPFGT and 0.16 mg/ml PH inhibited candidal growth by 88% and EPS secretion by 74% according to CSLM. A reduction in biofilm formation and in the transition from yeast to hyphal morphotype was observed using SEM. A strong reduction was found in the expression of hwp1, eap1, and als3 virulence associated genes. These results demonstrate the inhibitory effect of natural PPFGT polyphenolic extraction on C. albicans biofilm formation and EPS secretion, alone and together with PH. In an era of increased drug resistance, the use of phytomedicine to constrain biofilm development, without killing host cells, may pave the way to a novel therapeutic concept, especially in children as orthodontic patients.

scholarly journals Fluorescence-Based Reporter for Gauging Cyclic Di-GMP Levels in Pseudomonas aeruginosa

2012 ◽  
Vol 78 (15) ◽  
pp. 5060-5069 ◽  
Author(s):  
Morten T. Rybtke ◽  
Bradley R. Borlee ◽  
Keiji Murakami ◽  
Yasuhiko Irie ◽  
Morten Hentzer ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Fluorescent Protein ◽  
Subsequent Development ◽  
Cellular Level ◽  
Host Immune System ◽  
Chronic Infections ◽  
Content Type ◽  
Genes Encoding ◽  
Green Fluorescent

ABSTRACTThe increased tolerance toward the host immune system and antibiotics displayed by biofilm-formingPseudomonas aeruginosaand other bacteria in chronic infections such as cystic fibrosis bronchopneumonia is of major concern. Targeting of biofilm formation is believed to be a key aspect in the development of novel antipathogenic drugs that can augment the effect of classic antibiotics by decreasing antimicrobial tolerance. The second messenger cyclic di-GMP is a positive regulator of biofilm formation, and cyclic di-GMP signaling is now regarded as a potential target for the development of antipathogenic compounds. Here we describe the development of fluorescent monitors that can gauge the cellular level of cyclic di-GMP inP. aeruginosa. We have created cyclic di-GMP level reporters by transcriptionally fusing the cyclic di-GMP-responsivecdrApromoter to genes encoding green fluorescent protein. We show that the reporter constructs give a fluorescent readout of the intracellular level of cyclic di-GMP inP. aeruginosastrains with different levels of cyclic di-GMP. Furthermore, we show that the reporters are able to detect increased turnover of cyclic di-GMP mediated by treatment ofP. aeruginosawith the phosphodiesterase inducer nitric oxide. Considering that biofilm formation is a necessity for the subsequent development of a chronic infection and therefore a pathogenicity trait, the reporters display a significant potential for use in the identification of novel antipathogenic compounds targeting cyclic di-GMP signaling, as well as for use in research aiming at understanding the biofilm biology ofP. aeruginosa.

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