scholarly journals Trigonella foenum-graceum(Seed) Extract Interferes with Quorum Sensing Regulated Traits and Biofilm Formation in the Strains ofPseudomonas aeruginosaandAeromonas hydrophila

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Fohad Mabood Husain ◽  
Iqbal Ahmad ◽  
Mohd Shahnawaz Khan ◽  
Nasser Abdulatif Al-Shabib
Keyword(s):  
Virulence Factors ◽  
Biofilm Formation ◽  
Significant Inhibition ◽  
Seed Extract ◽  
Methanol Fraction ◽  
Swarming Motility ◽  
C Elegans ◽  
Medicinal Properties ◽  
Aquatic Pathogen

Trigonella foenum-graecumL. (Fenugreek) is an important plant of the Leguminosae family known to have medicinal properties. However, fraction based antiquorum sensing and antibiofilm activities have not been reported from this plant. In the present studyT. foenum-graecumseed extract was sequentially fractionated and sub-MICs were tested for above activities. The methanol fraction of the extract demonstrated significant inhibition of AHL regulated virulence factors: protease, LasB elastase, pyocyanin production, chitinase, EPS, and swarming motility inPseudomonas aeruginosaPAO1 and PAF79. Further, QS dependent virulence factor in the aquatic pathogenAeromonas hydrophilaWAF38 was also reduced. Application ofT. foenum-graecumseed extract to PAO1, PAF79, and WAF38 decreased the biofilm forming abilities of the pathogens by significant levels. The extract also exhibited reduced AHL levels and subsequent downregulation oflasBgene.In vivostudy showed an enhanced survival of PAO1-preinfectedC. elegansafter treatment with extract at 1 mg/mL. Further, the major compound detected by GC-MS, caffeine, reduced the production of QS regulated virulence factors and biofilm at 200 µg/mL concentration indicating its role in the activity of the methanol extract. The results of the present study reveal the potential anti-QS and antibiofilm property ofT. foenum-graceumextract and caffeine.

scholarly journals Xylitol Inhibits Growth and Blocks Virulence in Serratia marcescens

2021 ◽  
Vol 9 (5) ◽  
pp. 1083
Author(s):  
Ahdab N. Khayyat ◽  
Wael A. H. Hegazy ◽  
Moataz A. Shaldam ◽  
Rasha Mosbah ◽  
Ahmad J. Almalki ◽  
...  
Keyword(s):  
Serratia Marcescens ◽  
Virulence Factors ◽  
Biofilm Formation ◽  
Therapeutic Option ◽  
Nosocomial Pathogen ◽  
Swarming Motility ◽  
Natural Ligand ◽  
In Silico Study ◽  
Virulence Factor Production

Serratia marcescens is an opportunistic nosocomial pathogen and causes wound and burn infections. It shows high resistance to antibiotics and its pathogenicity is mediated by an arsenal of virulence factors. Another therapeutic option to such infections is targeting quorum sensing (QS), which controls the expression of different S. marcescens virulence factors. Prevention of QS can deprive S. marcescens from its bacterial virulence without applying stress on the bacterial growth and facilitates the eradication of the bacteria by immunity. The objective of the current study is to explore the antimicrobial and antivirulence activities of xylitol against S. marcescens. Xylitol could inhibit the growth of S. marcescens. Sub-inhibitory concentrations of xylitol could inhibit biofilm formation, reduce prodigiosin production, and completely block protease activity. Moreover, xylitol decreased swimming motility, swarming motility and increased the sensitivity to hydrogen peroxide. The expression of rsmA, pigP, flhC, flhD fimA, fimC, shlA bsmB, and rssB genes that regulate virulence factor production was significantly downregulated by xylitol. In silico study showed that xylitol could bind with the SmaR receptor by hydrophobic interaction and hydrogen bonding, and interfere with the binding of the natural ligand with SmaR receptor. An in vivo mice survival test confirmed the ability of xylitol to protect mice against the virulence of S. marcescens. In conclusion, xylitol is a growth and virulence inhibitor in S. marcescens and can be employed for the treatment of S. marcescens wound and burn infections.

scholarly journals Paeonol Attenuates Quorum-Sensing Regulated Virulence and Biofilm Formation in Pseudomonas aeruginosa

2021 ◽  
Vol 12 ◽  
Author(s):  
Dan Yang ◽  
Suqi Hao ◽  
Ling Zhao ◽  
Fei Shi ◽  
Gang Ye ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Virulence Factors ◽  
Biofilm Formation ◽  
Resistant Bacteria ◽  
Infection Model ◽  
Dependent Manner ◽  
Gram Negative ◽  
C Elegans

With the prevalence of multidrug-resistant bacteria and clinical -acquired pathogenic infections, the development of quorum-sensing (QS) interfering agents is one of the most potential strategies to combat bacterial infections and antibiotic resistance. Chinese herbal medicines constitute a valuable bank of resources for the identification of QS inhibitors. Accordingly, in this research, some compounds were tested for QS inhibition using indicator strains. Paeonol is a phenolic compound, which can effectively reduce the production of violacein without affecting its growth in Chromobacterium violaceum ATCC 12472, indicating its excellent anti-QS activity. This study assessed the anti-biofilm activity of paeonol against Gram-negative pathogens and investigated the effect of paeonol on QS-regulated virulence factors in Pseudomonas aeruginosa. A Caenorhabditis elegans infection model was used to explore the anti-infection ability of paeonol in vivo. Paeonol exhibited an effective anti-biofilm activity against Gram-negative bacteria. The ability of paeonol to interfere with the AHL-mediated quorum sensing systems of P. aeruginosa was determined, found that it could attenuate biofilm formation, and synthesis of pyocyanin, protease, elastase, motility, and AHL signaling molecule in a concentration- and time-dependent manner. Moreover, paeonol could significantly downregulate the transcription level of the QS-related genes of P. aeruginosa including lasI/R, rhlI/R, pqs/mvfR, as well as mediated its virulence factors, lasA, lasB, rhlA, rhlC, phzA, phzM, phzH, and phzS. In vivo studies revealed that paeonol could reduce the pathogenicity of P. aeruginosa and enhance the survival rate of C. elegans, showing a moderate protective effect on C. elegans. Collectively, these findings suggest that paeonol attenuates bacterial virulence and infection of P. aeruginosa and that further research elucidating the anti-QS mechanism of this compound in vivo is warranted.

scholarly journals Attenuation of Aeromonas hydrophila Infection in Carassius auratus by YtnP, a N-acyl Homoserine Lactonase from Bacillus licheniformis T-1

Antibiotics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 631
Author(s):  
Mengfan Peng ◽  
Wentao Tong ◽  
Zhen Zhao ◽  
Ling Xiao ◽  
Zhaoyue Wang ◽  
...  
Keyword(s):  
Virulence Factors ◽  
Bacillus Licheniformis ◽  
Aeromonas Hydrophila ◽  
Biofilm Formation ◽  
Carassius Auratus ◽  
Quorum Quenching ◽  
Inhibition Rate ◽  
Sequence Identity

In this experiment, the quorum quenching gene ytnP of Bacillus licheniformis T-1 was cloned and expressed, and the effect against infection of Aeromonas hydrophila ATCC 7966 was evaluated in vitro and vivo. The BLAST results revealed a 99% sequence identity between the ytnP gene of T-1 and its homolog in B.subtilis sub sp. BSP1, and the dendroGram showed that the similarity in the YtnP protein in T-1 was 100% in comparison with B.subtilis 3610, which was categorized as the Aidc cluster of the MBL family. The AHL lactonase activity of the purified YtnP was detected as 1.097 ± 0.7 U/mL with C6-HSL as the substrate. Otherwise, purified YtnP protein could significantly inhibit the biofilm formation of A.hydrophila ATCC 7966 with an inhibition rate of 68%. The MIC of thiamphenicol and doxycycline hydrochloride against A. hydrophila reduced from 4 μg/mL and 0.5 μg/mL to 1 μg/mL and 0.125 μg/mL, respectively, in the presence of YtnP. In addition, YtnP significantly inhibited the expression of five virulence factors hem, ahyB, ast, ep, aerA of A. hydrophila ATCC 7966 as well (p < 0.05). The results of inhibition on virulence showed a time-dependence tendency, while the strongest anti-virulence effects were within 4–24 h. In vivo, when the YtnP protein was co-injected intraperitoneally with A. hydrophila ATCC 7966, it attenuated the pathogenicity of A. hydrophila and the accumulated mortality was 27 ± 4.14% at 96 h, which was significantly lower than the average mortality of 78 ± 2.57% of the Carassius auratus injected with 108 CFU/mL of A. hydrophila ATCC 7966 only (p < 0.001). In conclusion, the AHL lactonase in B. licheniformis T-1 was proven to be YtnP protein and could be developed into an agent against infection of A. hydrophila in aquaculture.

scholarly journals Anti-quorum Sensing Potential of Ageratum Conyzoides L. (Asteraceae) Extracts

2021 ◽  
Author(s):  
Eli COMPAORE ◽  
Moussa COMPAORE ◽  
Vincent OUEDRAOGO ◽  
Ablassé ROUAMBA ◽  
Martin KIENDREBEOGO
Keyword(s):  
Quorum Sensing ◽  
Virulence Factors ◽  
Biofilm Formation ◽  
Pathogenic Bacteria ◽  
Methanolic Extract ◽  
Negative Impact ◽  
Significant Inhibition ◽  
High Morbidity ◽  
Ageratum Conyzoides ◽  
Phytochemical Content

Abstract Background: Pseudomonas aeruginosa causes infections in human particularly immunocompromised patients with cystic fibrosis, severe burns and HIV, resulting in high morbidity and mortality. The pathogenic bacteria P aeruginosa produces virulence factors regulated by the mechanism called quorum sensing system. Objective: The aim of this study was to assess the anti-quorum sensing activity of Ageratum conyzoides extracts Method: Chromobacterium violaceum reporter strain CV026 was used to highlight any interference with bacterium QS and strains derived from P. aeruginosa PAO1 were used to reveal any interference with the expression of quorum sensing genes, and to assess any impact of extract on the kinetics of the production of pyocyanin, elastases and biofilm formation. Results: Hydro-methanolic extract at the sub-inhibitory concentration of 100 μg/mL reduced quorum sensing virulence factors production such as, pyocyanin, elastases, rhamnolipids and biofilm formation in P. aeruginosa PAO1 after 18 hours monitoring. Extract showed significant inhibition in HSL-mediated violacein production on C. violaceum CV026 after 48 hours monitoring. Biofilm formation was inhibited up to 32%. It affected QS gene expression in PAO1. The regulatory genes lasR / rhlR and the lasI synthases were most affected. At 8hours, hydro-methanolic extract reduced both QS gene to more than 30% (lasI/lasR and rhlI/R respectively 33.8% /30.2% and 36% /33.2%). RhlA and lasB genes have been relatively affected (13.4% and 28.9%). After 18 h, this extract reduced significantly the expression of regulatory 30 genes lasR (31%) and rhlR (39.6%) although synthases genes seemed to be less affected (lasI/21.2% and rhlI/11.6%). A limited impact was observed on the downstream genes (lasB /20.0% and rhlA /15.3%). No negative impact was observed on CV026 and PAO1 growth and cell viability. Our study also showed that A. conyzoides having ample amount of phenolics, flavonoids and triterpenoids. This phytochemical content could be one of the factors for showing anti quorum potential. Conclusion: Results indicate that hydro methanol 80 % extract from A. conyzoides could be a source of potential QS inhibition compounds.

scholarly journals Identification of gmhA, a Yersinia pestis Gene Required for Flea Blockage, by Using a Caenorhabditis elegans Biofilm System

2005 ◽  
Vol 73 (11) ◽  
pp. 7236-7242 ◽  
Author(s):  
Creg Darby ◽  
Sandya L. Ananth ◽  
Li Tan ◽  
B. Joseph Hinnebusch
Keyword(s):  
Caenorhabditis Elegans ◽  
Yersinia Pestis ◽  
Biofilm Formation ◽  
Yersinia Pseudotuberculosis ◽  
C Elegans ◽  
Transposon Insertion ◽  
Insertion Mutants ◽  
Random Screening

ABSTRACT Yersinia pestis, the cause of bubonic plague, blocks feeding by its vector, the flea. Recent evidence indicates that blockage is mediated by an in vivo biofilm. Y. pestis and the closely related Yersinia pseudotuberculosis also make biofilms on the cuticle of the nematode Caenorhabditis elegans, which block this laboratory animal's feeding. Random screening of Y. pseudotuberculosis transposon insertion mutants with a C. elegans biofilm assay identified gmhA as a gene required for normal biofilms. gmhA encodes phosphoheptose isomerase, an enzyme required for synthesis of heptose, a conserved component of lipopolysaccharide and lipooligosaccharide. A Y. pestis gmhA mutant was constructed and was severely defective for C. elegans biofilm formation and for flea blockage but only moderately defective in an in vitro biofilm assay. These results validate use of the C. elegans biofilm system to identify genes and pathways involved in Y. pestis flea blockage.

scholarly journals Plantain Herb Extracts significantly attenuate the quorum sensing-controlled virulence factors and inhibit biofilm formation in Pseudomonas aeruginosa PAO1

2019 ◽  
Vol 78 ◽  
pp. 01004
Author(s):  
Shan Li ◽  
Jiangning Yao ◽  
Haoming Li
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Virulence Factors ◽  
Biofilm Formation ◽  
Opportunistic Pathogen ◽  
Significant Inhibition ◽  
Control Group ◽  
Produce Cell ◽  
Group B ◽  
Herb Extracts

Pseudomonas aeruginosa is a Gram-negative organism that can survive under harsh conditions, and it is also an opportunistic pathogen that can produce cell-associated extracellular virulence factors. Several of these virulence factors have been demonstrated to be regulated by quorum sensing (QS). Plantain Herb has been used as antibacterial agents for many centuries in China. In this study, we analyzed Plantain Herb Extracts (PHE) at the concentration of 16 μg/mL (Group A, MIC), 8 μg/mL (Group B, 1/2 MIC) and 4 μg/mL (Group C, 1/4 MIC) for inhibition of the virulence factors production and biofilm formation in P. aeruginosa PAO1. The virulence factors included pyocyanin, rhamnolipids, protease and alginate. PHE showed significant inhibition of virulence factors as compared to the control group without interfering its growth. Thus, PHE might be a potent QS inhibitor and anti-biofilm agent in the treatment of Pseudomonas aeruginosa infections.

scholarly journals Caenorhabditis elegans as an Infection Model for Pathogenic Mold and Dimorphic Fungi: Applications and Challenges

2021 ◽  
Vol 11 ◽  
Author(s):  
Chukwuemeka Samson Ahamefule ◽  
Blessing C. Ezeuduji ◽  
James C. Ogbonna ◽  
Anene N. Moneke ◽  
Anthony C. Ike ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Filamentous Fungi ◽  
Virulence Factors ◽  
Antifungal Agents ◽  
Fungal Infections ◽  
Pathogenic Fungi ◽  
Infection Model ◽  
Dimorphic Fungi ◽  
C Elegans

The threat burden from pathogenic fungi is universal and increasing with alarming high mortality and morbidity rates from invasive fungal infections. Understanding the virulence factors of these fungi, screening effective antifungal agents and exploring appropriate treatment approaches in in vivo modeling organisms are vital research projects for controlling mycoses. Caenorhabditis elegans has been proven to be a valuable tool in studies of most clinically relevant dimorphic fungi, helping to identify a number of virulence factors and immune-regulators and screen effective antifungal agents without cytotoxic effects. However, little has been achieved and reported with regard to pathogenic filamentous fungi (molds) in the nematode model. In this review, we have summarized the enormous breakthrough of applying a C. elegans infection model for dimorphic fungi studies and the very few reports for filamentous fungi. We have also identified and discussed the challenges in C. elegans-mold modeling applications as well as the possible approaches to conquer these challenges from our practical knowledge in C. elegans-Aspergillus fumigatus model.

scholarly journals Cephalosporins target quorum sensing and suppress virulence of Pseudomonas aeruginosa in Caenorhabditis elegans infection model

2020 ◽  
Author(s):  
Lokender Kumar ◽  
Nathanael Brenner ◽  
John Brice ◽  
Judith Klein-Seetharaman ◽  
Susanta K. Sarkar
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Caenorhabditis Elegans ◽  
Quorum Sensing ◽  
Virulence Factors ◽  
Biofilm Formation ◽  
Host Cells ◽  
Infection Model ◽  
Host Immune System ◽  
Bacterial Cells

ABSTRACTPseudomonas aeruginosa utilizes a chemical social networking system referred to as quorum sensing (QS) to strategically co-ordinate the expression of virulence factors and biofilm formation. Virulence attributes damage the host cells, impair the host immune system, and protect bacterial cells from antibiotic attack. Thus, anti-QS agents may act as novel anti-infective therapeutics to treat P. aeruginosa infections. The present study was performed to evaluate the anti-QS, anti-biofilm, and anti-virulence activity of β-lactam antibiotics (carbapenems and cephalosporins) against P. aeruginosa. The anti-QS activity was quantified using Chromobacterium violaceum CV026 as a QS reporter strain. Our results showed that cephalosporins including cefepime (CP), ceftazidime (CF), and ceftriaxone (CT) exhibited potent anti-QS and anti-virulence activities against P. aeruginosa PAO1. These antibiotics significantly impaired motility phenotypes, decreased pyocyanin production, and reduced the biofilm formation by P. aeruginosa PAO1. In the present study, we studied isogenic QS mutants of PAO1: ΔLasR, ΔRhlR, ΔPqsA, and ΔPqsR and found that the levels of virulence factors of antibiotic-treated PAO1 were comparable to QS mutant strains. Molecular docking predicted high binding affinities of cephalosporins for the ligand-binding pocket of QS receptors (CviR, LasR, and PqsR). In addition, our results showed that the anti-microbial activity of aminoglycosides increased in the presence of sub-inhibitory concentrations (sub-MICs) of CP against P. aeruginosa PAO1. Further, utilizing Caenorhabditis elegans as an animal model for the in vivo anti-virulence effects of antibiotics, cephalosporins showed a significant increase in C. elegans survival by suppressing virulence factor production in P. aeruginosa. Thus, our results indicate that cephalosporins might provide a viable anti-virulence therapy in the treatment of infections caused by multi-drug resistant P. aeruginosa.

scholarly journals Characterization of Salmonella Dublin isolated from bovine and human hosts

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Narayan Paudyal ◽  
Hang Pan ◽  
Mohammed Elbediwi ◽  
Xiao Zhou ◽  
Xianqi Peng ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Systemic Disease ◽  
Acquired Resistance ◽  
Infection Model ◽  
Phenotypic Properties ◽  
Swarming Motility ◽  
C Elegans ◽  
Broth Microdilution Method ◽  
Animal Isolates ◽  
Vi Antigen

Abstract Background Salmonella enterica subsp. enterica serovar Dublin (S. Dublin), a cattle adapted serovar causes enteritis, and systemic disease in bovines. The invasive index of this serovar far exceeds that of the other serovars and human infections often present as fatal or highly resistant infections. In this, observational study, phenotypic properties of human and bovine-derived isolates of S. Dublin along with antibiogram of common antimicrobials were evaluated. The multiplex PCR confirmed isolates were genotyped using 7-gene legacy MLST. MIC assay was done by broth microdilution method. Previously published protocols were used to assess the motility, biofilm formation and morphotype. Vi antigen was agglutinated using commercial antiserum. Caenorhabditis elegans infection model was used to evaluate the virulence potiential. Phenotyping experiments were done in duplicates while virulence assay was done in triplicates. Whole-genome sequencing was used to predict the genes responsible for acquired resistance and a genotype-phenotype comparison was made. Results We evaluated 96 bovine and 10 human isolates in this study. All the isolates belonged to ST10 in eBG53 and were negative for Vi-antigen. The swarming motility, biofilm formation and morphotype were variable in the isolates of both groups. Resistance to sulfamethoxazole, ampicillin, chloramphenicol, tetracycline was > 90% in animal isolates whereas resistance to sulfamethoxazole was > 70% in human isolates. MDR was also higher in animal isolates. Human isolates were significantly (P < 0.0001) more virulent than animal isolates on C. elegans infection model. The genomic comparison based on the core SNPs showed a high degree of homogeneity between the isolates. The carriage of IncA/C2 plasmid was seen as a typical feature of isolates from the bovine hosts. Conclusion Human isolates showed more diversity in the phenotypic assays. Animal isolates showed a higher degree of antimicrobial resistance with greater MDR but human isolates formed more biofilm and had greater swarming motility as well as increased virulence to the nematode C. elegans. The carriage of IncA/C2 plasmid could contribute to the distinguishing feature of the bovine isolates. The tandem use of genotypic-phenotypic assays improves the understanding of diversity and differential behaviour of the same serovar from unrelated host sources.

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