scholarly journals BIOFILM FORMATION AND QUORUM SENSING ANALYSIS OF UROPATHOGENIC MULTIDRUG RESISTANCE ESCHERICHIA COLI

2021 ◽  
pp. 61-63
Author(s):  
MOHANA PRIYA M. ◽  
G. BHUVANESHWARI
Keyword(s):  
Escherichia Coli ◽  
Multidrug Resistance ◽  
Quorum Sensing ◽  
Biofilm Formation ◽  
Homoserine Lactone ◽  
Retardation Factor ◽  
Clinical Microbiology Laboratory ◽  
Acyl Homoserine Lactone ◽  
Chromatography Method ◽  
E Coli

Objective: Escherichia coli (E. coli) are gram-negative facultative anaerobes which are commonly found in the lower intestine. Biofilm production in E. coli promotes colonization and leads to an increase rate of infections, and such infections may be difficult to treat as they exhibit multidrug resistance (MDR). Methods: 50 strains of uropathogenic E. coli were collected from Clinical Microbiology laboratory at Saveetha medical college and hospital for a time period of 3 mo. Strains were identified by conventional biochemical methods. Biofilm formation and quorum sensing analysis were performed by the Microtitre plate method and Thin Layer Chromatography method (TLC), respectively. Results: In this study, 46 (92%) of E. coli strains were strong, 3(6%) were intermediate and 1(2%) were weak biofilm producers. From TLC analysis, 34 (68%) of the strains produced Acyl Homoserine Lactone molecules. Out of which, 16 isolates were shown unknown analytes of Retardation factor (Rf) value greater than 1. The Rf values identified were 3 unsubstituted C4 (5), 3 unsubstituted C6 (3), 3 oxo C8 (3), 3 oxo C4 (4), 3 oxo C6 (2), 3 oxo C1 (1). Conclusion: In this study, 100% of isolates were biofilm producers. Of which 18 strains produced known Acyl Homoserine Lactone molecules and 16 isolates produced unknown analytes. Thus, quorum sensing molecules plays a major role in biofilm formation.

scholarly journals Role of Quorum Sensing and Antimicrobial Component Production by Serratia plymuthica in Formation of Biofilms, Including Mixed Biofilms with Escherichia coli

2006 ◽  
Vol 72 (11) ◽  
pp. 7294-7300 ◽  
Author(s):  
Pieter Moons ◽  
Rob Van Houdt ◽  
Abram Aertsen ◽  
Kristof Vanoirbeek ◽  
Yves Engelborghs ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Quorum Sensing ◽  
Biofilm Formation ◽  
Homoserine Lactone ◽  
Broth Culture ◽  
Confocal Laser ◽  
Wild Type ◽  
Serratia Plymuthica ◽  
E Coli

ABSTRACT We have previously characterized the N-acyl-l-homoserine lactone-based quorum-sensing system of the biofilm isolate Serratia plymuthica RVH1. Here we investigated the role of quorum sensing and of quorum-sensing-dependent production of an antimicrobial compound (AC) on biofilm formation by RVH1 and on the cocultivation of RVH1 and Escherichia coli in planktonic cultures or in biofilms. Biofilm formation of S. plymuthica was not affected by the knockout of splI or splR, the S. plymuthica homologs of the luxI or luxR quorum-sensing gene, respectively, or by the knockout of AC production. E. coli grew well in mixed broth culture with RVH1 until the latter reached 8.5 to 9.5 log CFU/ml, after which the E. coli colony counts steeply declined. In comparison, only a very small decline occurred in cocultures with the S. plymuthica AC-deficient and splI mutants. Complementation with exogenous N-hexanoyl-l-homoserine lactone rescued the wild-type phenotype of the splI mutant. The splR knockout mutant also induced a steep decline of E. coli, consistent with its proposed function as a repressor of quorum-sensing-regulated genes. The numbers of E. coli in 3-day-old mixed biofilms followed a similar pattern, being higher with S. plymuthica deficient in SplI or AC production than with wild-type S. plymuthica, the splR mutant, or the splI mutant in the presence of N-hexanoyl-l-homoserine lactone. Confocal laser scanning microscopic analysis of mixed biofilms established with strains producing different fluorescent proteins showed that E. coli microcolonies were less developed in the presence of RVH1 than in the presence of the AC-deficient mutant.

scholarly journals The Acyl Homoserine Lactone Receptor, SdiA, of Escherichia coli and Salmonella enterica Serovar Typhimurium Does Not Respond to Indole

2012 ◽  
Vol 78 (15) ◽  
pp. 5424-5431 ◽  
Author(s):  
Anice Sabag-Daigle ◽  
Jitesh A. Soares ◽  
Jenée N. Smith ◽  
Mohamed E. Elmasry ◽  
Brian M. M. Ahmer
Keyword(s):  
Escherichia Coli ◽  
Salmonella Enterica ◽  
Biofilm Formation ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Homoserine Lactone ◽  
Acyl Homoserine Lactone ◽  
Content Type ◽  
E Coli ◽  
Serovar Typhimurium ◽  
High Concentrations

ABSTRACTIn this study, we tested the hypothesis that the SdiA proteins ofEscherichia coliandSalmonella entericaserovar Typhimurium respond to indole. While indole was found to have effects on gene expression and biofilm formation, these effects were notsdiAdependent. However, high concentrations of indole did inhibitN-acyl-l-homoserine lactone (AHL) sensing by SdiA. We conclude that SdiA does not respond to indole but indole can inhibit SdiA activity inE. coliandSalmonella.

scholarly journals The Burkholderia mallei BmaR3-BmaI3 Quorum-Sensing System Produces and Responds to N-3-Hydroxy-Octanoyl Homoserine Lactone

2008 ◽  
Vol 190 (14) ◽  
pp. 5137-5141 ◽  
Author(s):  
Breck A. Duerkop ◽  
Jake P. Herman ◽  
Ricky L. Ulrich ◽  
Mair E. A. Churchill ◽  
E. Peter Greenberg
Keyword(s):  
Escherichia Coli ◽  
Quorum Sensing ◽  
Homoserine Lactone ◽  
Acyl Homoserine Lactone ◽  
Burkholderia Mallei ◽  
E Coli ◽  
Additional Signal ◽  
Sensing System ◽  
Quorum Sensing System ◽  
Signal Receptors

ABSTRACT Burkholderia mallei has two acyl-homoserine lactone (acyl-HSL) signal generator-receptor pairs and two additional signal receptors, all of which contribute to virulence. We show that B. mallei produces N-3-hydroxy-octanoyl HSL (3OHC8-HSL) but a bmaI3 mutant does not. Recombinant Escherichia coli expressing BmaI3 produces hydroxylated acyl-HSLs, with 3OHC8-HSL being the most abundant compound. In recombinant E. coli, BmaR3 responds to 3OHC8-HSL but not to other acyl-HSLs. These data indicate that the signal for BmaR3-BmaI3 quorum sensing is 3OHC8-HSL.

Biofilm Formation, Communication and Interactions of Mesophilic Leaching Bacteria during Pyrite Oxidation

2013 ◽  
Vol 825 ◽  
pp. 107-110
Author(s):  
Sören Bellenberg ◽  
Robert Barthen ◽  
Mario Vera ◽  
Nicolas Guiliani ◽  
Wolfgang Sand
Keyword(s):  
Quorum Sensing ◽  
Acidithiobacillus Ferrooxidans ◽  
Biofilm Formation ◽  
Pyrite Oxidation ◽  
Cell Communication ◽  
Homoserine Lactone ◽  
Mixed Cultures ◽  
Acyl Homoserine Lactone ◽  
Leaching Bacteria ◽  
Leaching Efficiency

A functional luxIR-type Quorum Sensing (QS) system is present in Acidithiobacillus ferrooxidans. However, cell-cell communication among various acidophilic chemolithoautotrophs growing on pyrite has not been studied in detail. These aspects are the scope of this study with emphasis on the effects exerted by the N-acyl-homoserine lactone (AHL) type signaling molecules which are produced by Acidithiobacillus ferrooxidans. Their effects on attachment and leaching efficiency by other leaching bacteria, such as Acidithiobacillus ferrivorans, Acidiferrobacter spp. SPIII/3 and Leptospirillum ferrooxidans in pure and mixed cultures growing on pyrite is shown.

Influence of Glucose Concentrations on Biofilm Formation, Motility, Exoprotease Production, and Quorum Sensing in Aeromonas hydrophila

2013 ◽  
Vol 76 (2) ◽  
pp. 239-247 ◽  
Author(s):  
IQBAL KABIR JAHID ◽  
NA-YOUNG LEE ◽  
ANNA KIM ◽  
SANG-DO HA
Keyword(s):  
Quorum Sensing ◽  
Aeromonas Hydrophila ◽  
Biofilm Formation ◽  
Opportunistic Pathogen ◽  
Homoserine Lactone ◽  
Protease Production ◽  
Acyl Homoserine Lactone ◽  
Human Pathogen ◽  
Initial Biofilm ◽  
Motility Inhibition

Aeromonas hydrophila recently has received increased attention because it is opportunistic and a primary human pathogen. A. hydrophila biofilm formation and its control are a major concern for food safety because biofilms are related to virulence. Therefore, we investigated biofilm formation, motility inhibition, quorum sensing, and exoprotease production of this opportunistic pathogen in response to various glucose concentrations from 0.05 to 2.5% (wt/vol). More than 0.05% glucose significantly impaired (P < 0.05) quorum sensing, biofilm formation, protease production, and swarming and swimming motility, whereas bacteria treated with 0.05% glucose had activity similar to that of the control (0% glucose). A stage shift biofilm assay revealed that the addition of glucose (2.5%) inhibited initial biofilm formation but not later stages. However, addition of quorum sensing molecules N-3-butanoyl-DL-homoserine lactone and N-3-hexanoyl homoserine lactone partially restored protease production, indicating that quorum sensing is controlled by glucose concentrations. Thus, glucose present in food or added as a preservative could regulate acyl-homoserine lactone quorum sensing molecules, which mediate biofilm formation and virulence in A. hydrophila.

scholarly journals Reversible Acyl-Homoserine Lactone Binding to Purified Vibrio fischeri LuxR Protein

2004 ◽  
Vol 186 (3) ◽  
pp. 631-637 ◽  
Author(s):  
M. L. Urbanowski ◽  
C. P. Lostroh ◽  
E. P. Greenberg
Keyword(s):  
Quorum Sensing ◽  
Promoter Region ◽  
Vibrio Fischeri ◽  
Homoserine Lactone ◽  
Acyl Homoserine Lactone ◽  
E Coli ◽  
High Affinity ◽  
Founding Member ◽  
Luxr Homolog

ABSTRACT The Vibrio fischeri LuxR protein is the founding member of a family of acyl-homoserine lactone-responsive quorum-sensing transcription factors. Previous genetic evidence indicates that in the presence of its quorum-sensing signal, N-(3-oxohexanoyl) homoserine lactone (3OC6-HSL), LuxR binds to lux box DNA within the promoter region of the luxI gene and activates transcription of the luxICDABEG luminescence operon. We have purified LuxR from recombinant Escherichia coli. Purified LuxR binds specifically and with high affinity to DNA containing a lux box. This binding requires addition of 3OC6-HSL to the assay reactions, presumably forming a LuxR-3OC6-HSL complex. When bound to the lux box at the luxI promoter in vitro, LuxR-3OC6-HSL enables E. coli RNA polymerase to initiate transcription from the luxI promoter. Unlike the well-characterized LuxR homolog TraR in complex with its signal (3-oxo-octanoyl-HSL), the LuxR-30C6-HSL complex can be reversibly inactivated by dilution, suggesting that 3OC6-HSL in the complex is not tightly bound and is in equilibrium with the bulk solvent. Thus, although LuxR and TraR both bind 3-oxoacyl-HSLs, the binding is qualitatively different. The differences have implications for the ways in which these proteins respond to decreases in signal concentrations or rapid drops in population density.

Role of N-acyl-homoserine lactone (AHL) based quorum sensing on biofilm formation on packing media in wastewater treatment process

RSC Advances ◽  
2016 ◽  
Vol 6 (14) ◽  
pp. 11128-11139 ◽  
Author(s):  
Huizhi Hu ◽  
Junguo He ◽  
Jian Liu ◽  
Huarong Yu ◽  
Jian Tang ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Quorum Sensing ◽  
Biofilm Formation ◽  
Treatment Process ◽  
Single Species ◽  
Homoserine Lactone ◽  
Acyl Homoserine Lactone ◽  
Wastewater Treatment Process

Quorum sensing (QS) signaling has been extensively studied in granules and single species populations.

scholarly journals Mechanistic analysis of a synthetic inhibitor of the Pseudomonas aeruginosa LasI quorum-sensing signal synthase

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
O. Lidor ◽  
A. Al-Quntar ◽  
E. C. Pesci ◽  
D. Steinberg
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
In Silico ◽  
Biofilm Formation ◽  
Homoserine Lactone ◽  
Site Directed Mutagenesis ◽  
Great Promise ◽  
Acyl Homoserine Lactone ◽  
Virulence Determinants

Abstract Pseudomonas aeruginosa is an opportunistic Gram-negative pathogen responsible for many human infections. LasI is an acyl-homoserine lactone synthase that produces a quorum-sensing (QS) signal that positively regulates numerous P. aeruginosa virulence determinants. The inhibition of the LasI protein is therefore an attractive drug target. In this study, a novel in silico to in vitro complementation was applied to screen thiazolidinedione-type compounds for their ability to inhibit biofilm formation at concentrations not affecting bacterial growth. The compound (z)-5-octylidenethiazolidine-2, 4-dione (TZD-C8) was a strong inhibitor of biofilm formation and chosen for further study. Structural exploration of in silico docking predicted that the compound had high affinity for the LasI activity pocket. The TZD-C8 compound was also predicted to create hydrogen bonds with residues Arg30 and Ile107. Site-directed mutagenesis (SDM) of these two sites demonstrated that TZD-C8 inhibition was abolished in the lasI double mutant PAO-R30D, I107S. In addition, in vitro swarming motility and quorum sensing signal production were affected by TZD-C 8, confirming this compound alters the cell to cell signalling circuitry. Overall, this novel inhibitor of P. aeruginosa quorum sensing shows great promise and validates our mechanistic approach to discovering inhibitors of LuxI-type acyl-homoserine lactone synthases.

scholarly journals Reconfiguring the Quorum-Sensing Regulator SdiA of Escherichia coli To Control Biofilm Formation via Indole and N-Acylhomoserine Lactones

2009 ◽  
Vol 75 (6) ◽  
pp. 1703-1716 ◽  
Author(s):  
Jintae Lee ◽  
Toshinari Maeda ◽  
Seok Hoon Hong ◽  
Thomas K. Wood
Keyword(s):  
Escherichia Coli ◽  
Quorum Sensing ◽  
Biofilm Formation ◽  
Transcriptome Profiling ◽  
Homoserine Lactone ◽  
Wild Type ◽  
Acylhomoserine Lactone ◽  
Induced Genes ◽  
Whole Transcriptome ◽  
Indole Synthesis

ABSTRACT SdiA is a homolog of quorum-sensing regulators that detects N-acylhomoserine lactone (AHL) signals from other bacteria. Escherichia coli uses SdiA to reduce its biofilm formation in the presence of both AHLs and its own signal indole. Here we reconfigured SdiA (240 amino acids) to control biofilm formation using protein engineering. Four SdiA variants were obtained with altered biofilm formation, including truncation variants SdiA1E11 (F7L, F59L, Y70C, M94K, and K153X) and SdiA14C3 (W9R, P49T, N87T, frameshift at N96, and L123X), which reduced biofilm formation by 5- to 20-fold compared to wild-type SdiA in the presence of endogenous indole. Whole-transcriptome profiling revealed that wild-type SdiA reduced biofilm formation by repressing genes related to indole synthesis and curli synthesis compared to when no SdiA was expressed, while variant SdiA1E11 induced genes related to indole synthesis in comparison to wild-type SdiA. These results suggested altered indole metabolism, and corroborating the DNA microarray results in regard to indole synthesis, variant SdiA1E11 produced ninefold more indole, which led to reduced swimming motility and cell density. Also, wild-type SdiA decreased curli production and tnaA transcription, while SdiA1E11 increased tnaA transcription (tnaA encodes tryptophanase, which forms indole) compared to wild-type SdiA. Hence, wild-type SdiA decreased biofilm formation by reducing curli production and motility, and SdiA1E11 reduced biofilm formation via indole. Furthermore, an AHL-sensitive variant (SdiA2D10, having four mutations at E31G, Y42F, R116H, and L165Q) increased biofilm formation sevenfold in the presence of N-octanoyl-dl-homoserine lactone and N-(3-oxododecatanoyl)-l-homoserine lactone. Therefore, SdiA can be evolved to increase or decrease biofilm formation, and biofilm formation may be controlled by altering sensors rather than signals.

scholarly journals Chemotaxis towards autoinducer 2 mediates autoaggregation in Escherichia coli

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Leanid Laganenka ◽  
Remy Colin ◽  
Victor Sourjik
Keyword(s):  
Escherichia Coli ◽  
Quorum Sensing ◽  
Biofilm Formation ◽  
Bacterial Species ◽  
Physiological Role ◽  
Growth Conditions ◽  
Signal Molecules ◽  
E Coli ◽  
Autoinducer 2 ◽  
Cell Densities

Abstract Bacteria communicate by producing and sensing extracellular signal molecules called autoinducers. Such intercellular signalling, known as quorum sensing, allows bacteria to coordinate and synchronize behavioural responses at high cell densities. Autoinducer 2 (AI-2) is the only known quorum-sensing molecule produced by Escherichia coli but its physiological role remains elusive, although it is known to regulate biofilm formation and virulence in other bacterial species. Here we show that chemotaxis towards self-produced AI-2 can mediate collective behaviour—autoaggregation—of E. coli. Autoaggregation requires motility and is strongly enhanced by chemotaxis to AI-2 at physiological cell densities. These effects are observed regardless whether cell–cell interactions under particular growth conditions are mediated by the major E. coli adhesin (antigen 43) or by curli fibres. Furthermore, AI-2-dependent autoaggregation enhances bacterial stress resistance and promotes biofilm formation.

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