scholarly journals The relationship between biofilm formation, genes of virulence and iron metabolism in Escherichia coli

2018 ◽  
Author(s):  
Lívia Handrová ◽  
Anna Čuvalová ◽  
Vladimír Kmeť
Keyword(s):  
Escherichia Coli ◽  
Iron Metabolism ◽  
Biofilm Formation ◽  
Bacterial Infections ◽  
Opportunistic Infections ◽  
Bacterial Species ◽  
Pcr Amplification ◽  
Bacterial Strains ◽  
E Coli ◽  
Wide Range

Escherichia coli is known as one of the bacterial species with the widest adaptability to variety of niches either within organisms or outside in environment. Most strains of E. coli are of low virulence and associated with opportunistic infections, whereas others are highly virulent. The success of E. coli in colonising such a wide range of hosts and environments is basically due to a noticeable ductility in exploiting the available resources. It is becoming increasingly clear that biofilms have an enormous impact on medicine because since 65% of animal and human bacterial infections involve biofilms. In present study, we isolated strains of E. coli from animals. 19 interesting isolates were selected and tested by PCR amplification to virulence – iutA, cvaC, iss, tsh, papC, kps, iha and iron metabolism genes – sitA, feoB, irp2, fyuA, iroN, ireA. The ability of biofilm formation was assessed in a quantitative assay using a microtiter-plate test. Bacterial strains were grown on BHI. We divided isolates of E. coli into four classes: very weak (63.0%), weak (10.5%), moderate (10.5%) and strong (16.0%) biofilm producers. Representation genes of virulence were highly in isolates from very weak biofilm producers – from 7 genes were 6 highly; only papC (P fimbrial adhesin) was low. Genes of iron metabolism were different. Genes – sitA, fyuA, ireA in strong isolates producing biofilm and feoB, irp2, iroN in weak producers were most represented. The results show possible relation between presence virulence factor and low biofilm formation.

scholarly journals Probiotic Escherichia coli strain Nissle 1917 outcompetes intestinalpathogens during biofilm formation

2010 ◽  
Vol 59 (4) ◽  
pp. 392-399 ◽  
Author(s):  
Viktoria Hancock ◽  
Malin Dahl ◽  
Per Klemm
Keyword(s):  
Escherichia Coli ◽  
Beneficial Effect ◽  
Biofilm Formation ◽  
Bacterial Infections ◽  
Coli Strain ◽  
Gastrointestinal Infections ◽  
E Coli ◽  
Wide Range ◽  
The World

Many bacterial infections are associated with biofilm formation. Bacterialbiofilms can develop on essentially all kinds of surfaces, producing chronicand often intractable infections. Escherichia coli is an importantpathogen causing a wide range of gastrointestinal infections. E. coli strain Nissle 1917 has been used for many decades as a probiotic againsta variety of intestinal disorders and is probably the best field-tested E. coli strain in the world. Here we have investigated the biofilm-formingcapacity of Nissle 1917. We found that the strain was a good biofilm former.Not only was it significantly better at biofilm formation than enteropathogenic,enterotoxigenic and enterohaemorrhagic E. coli strains, it was alsoable to outcompete such strains during biofilm formation. The results supportthe notion of bacterial prophylaxis employing Nissle 1917 and may partiallyexplain why the strain has a beneficial effect on many intestinal disorders.

scholarly journals Multi-omic surveillance of Escherichia coli and Klebsiella spp. in hospital sink drains and patients

2020 ◽  
Author(s):  
B Constantinides ◽  
KK Chau ◽  
TP Quan ◽  
G Rodger ◽  
M Andersson ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Resistance Genes ◽  
Bacterial Infections ◽  
Wide Spectrum ◽  
Klebsiella Oxytoca ◽  
Clinical Disease ◽  
E Coli ◽  
Antimicrobial Resistance Genes ◽  
Wide Range

ABSTRACTEscherichia coli and Klebsiella spp. are important human pathogens that cause a wide spectrum of clinical disease. In healthcare settings, sinks and other wastewater sites have been shown to be reservoirs of antimicrobial-resistant E. coli and Klebsiella spp., particularly in the context of outbreaks of resistant strains amongst patients. Without focusing exclusively on resistance markers or a clinical outbreak, we demonstrate that many hospital sink drains are abundantly and persistently colonised with diverse populations of E. coli, Klebsiella pneumoniae and Klebsiella oxytoca, including both antimicrobial-resistant and susceptible strains. Using whole genome sequencing (WGS) of 439 isolates, we show that environmental bacterial populations are largely structured by ward and sink, with only a handful of lineages, such as E. coli ST635, being widely distributed, suggesting different prevailing ecologies which may vary as a result of different inputs and selection pressures. WGS of 46 contemporaneous patient isolates identified one (2%; 95% CI 0.05-11%) E. coli urine infection-associated isolate with high similarity to a prior sink isolate, suggesting that sinks may contribute to up to 10% of infections caused by these organisms in patients on the ward over the same timeframe. Using metagenomics from 20 sink-timepoints, we show that sinks also harbour many clinically relevant antimicrobial resistance genes including blaCTX-M, blaSHV and mcr, and may act as niches for the exchange and amplification of these genes. Our study reinforces the potential role of sinks in contributing to Enterobacterales infection and antimicrobial resistance in hospital patients, something that could be amenable to intervention.IMPORTANCEEscherichia coli and Klebsiella spp. cause a wide range of bacterial infections, including bloodstream, urine and lung infections. Previous studies have shown that sink drains in hospitals may be part of transmission chains in outbreaks of antimicrobial-resistant E. coli and Klebsiella spp., leading to colonisation and clinical disease in patients. We show that even in non-outbreak settings, contamination of sink drains by these bacteria is common across hospital wards, and that many antimicrobial resistance genes can be found and potentially exchanged in these sink drain sites. Our findings demonstrate that the colonisation of handwashing sink drains by these bacteria in hospitals is likely contributing to some infections in patients, and that additional work is needed to further quantify this risk, and to consider appropriate mitigating interventions.

scholarly journals Bioinformatic and Molecular Analysis of Inverse Autotransporters from Escherichia coli

mSphere ◽  
2019 ◽  
Vol 4 (4) ◽  
Author(s):  
Kelvin G. K. Goh ◽  
Danilo G. Moriel ◽  
Steven J. Hancock ◽  
Minh-Duy Phan ◽  
Mark A. Schembri
Keyword(s):  
Escherichia Coli ◽  
Cell Surface ◽  
Biofilm Formation ◽  
Secretion System ◽  
Content Type ◽  
E Coli ◽  
Wide Range ◽  
Type V Secretion ◽  
K 12 ◽  
Type V

ABSTRACT Proteins secreted by the type V secretion system possess multiple functions, including the capacity to mediate adhesion, aggregation, and biolfilm formation. The type V secretion system can be divided into five subclasses, one of which is the type Ve system. Proteins of the type Ve secretion system are also referred to as inverse autotransporters (IATs). In this study, we performed an in silico analysis of 126 completely sequenced Escherichia coli genomes available in the NCBI database and identified several distinct IAT-encoding gene families whose distribution varied throughout the E. coli phylogeny. The genes included three characterized IATs (intimin, fdeC, and yeeJ) and four uncharacterized IATs (here named iatA, iatB, iatC, and iatD). The four iat genes were cloned from the completely sequenced environmental E. coli strain SMS-3-5 and characterized. Three of these IAT proteins (IatB, IatC, and IatD) were expressed at the cell surface and possessed the capacity to mediate biofilm formation in a recombinant E. coli K-12 strain. Further analysis of the iatB gene, which showed a unique association with extraintestinal E. coli strains, suggested that its regulation is controlled by the LeuO global regulator. Overall, this study provides new data describing the prevalence, sequence variation, domain structure, function, and regulation of IATs found in E. coli. IMPORTANCE Escherichia coli is one of the most prevalent facultative anaerobes of the human gut. E. coli normally exists as a harmless commensal but can also cause disease following the acquisition of genes that enhance its pathogenicity. Adhesion is an important first step in colonization of the host and is mediated by an array of cell surface components. In E. coli, these include a family of adhesins secreted by the type V secretion system. Here, we identified and characterized new proteins from an emerging subclass of the type V secretion system known as the inverse autotransporters (IATs). We found that IAT-encoding genes are present in a wide range of strains and showed that three novel IATs were localized on the E. coli cell surface and mediated biofilm formation. Overall, this study provides new insight into the prevalence, function, and regulation of IATs in E. coli.

scholarly journals IscR Controls Iron-Dependent Biofilm Formation in Escherichia coli by Regulating Type I Fimbria Expression

2008 ◽  
Vol 191 (4) ◽  
pp. 1248-1257 ◽  
Author(s):  
Yun Wu ◽  
F. Wayne Outten
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Developmental Process ◽  
Bacterial Species ◽  
Type I ◽  
Surface Attachment ◽  
Environmental Signals ◽  
Regulatory Pathways ◽  
E Coli ◽  
Type I Fimbriae

ABSTRACT Biofilm formation is a complex developmental process regulated by multiple environmental signals. In addition to other nutrients, the transition metal iron can also regulate biofilm formation. Iron-dependent regulation of biofilm formation varies by bacterial species, and the exact regulatory pathways that control iron-dependent biofilm formation are often unknown or only partially characterized. To address this gap in our knowledge, we examined the role of iron availability in regulating biofilm formation in Escherichia coli. The results indicate that biofilm formation is repressed under low-iron conditions in E. coli. Furthermore, a key iron regulator, IscR, controls biofilm formation in response to changes in cellular Fe-S homeostasis. IscR regulates the FimE recombinase to control expression of type I fimbriae in E. coli. We propose that iron-dependent regulation of FimE via IscR leads to decreased surface attachment and biofilm dispersal under iron-limiting conditions.

Phytochemical Extracts of Leucas Aspera and Dahlia Pinnata Exhibit Antimicrobial Properties on Escherichia Coli and Enterococcus Faecalis.

2020 ◽  
Vol 09 ◽  
Author(s):  
Yamuna Saravanan ◽  
Bala Subramaniam Devaraj ◽  
Nithesh Kumar Velusamy ◽  
Pooja Shree Soundirarajan ◽  
Kumaravel Kandaswamy
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Activity ◽  
Enterococcus Faecalis ◽  
Bacterial Infections ◽  
Aqueous Extracts ◽  
Bacterial Strains ◽  
Efficacy Evaluation ◽  
E Coli ◽  
Methanol Extracts ◽  
Leucas Aspera

Background:: Phytochemicals such as tannins, alkaloids, flavonoids, and peptides been found to have antimicrobial activity against a variety of bacterial strains. Objective:: However, optimal extraction procedures for these phytochemicals and their efficacy evaluation against certain pathogenic bacterial strains remain unclear. Method:: Therefore, in this study phytochemicals from Leucas aspera (L. aspera) and Dahlia pinnata (D. pinnata) were extracted by hot and cold extraction methods using water and methanol as solvents. In addition, antimicrobial activity of L. aspera and D. pinnata extracts against bacterial strains such as the gram-negative Escherichia coli (E. coli) and the gram-positive Enterococcus faecalis (E. faecalis) were performed by Minimal Inhibitory Concentration (MIC) and CFU quantification assays. Results:: The majority of the phytochemicals such as protein, carbohydrate, tannins, flavonoids, phenols, and saponins were present in our extracts but steroids were absent in the extract. Protein, tannins, flavonoids, phenols, and saponins were present in both L. aspera and D. pinnata. The yield of proteins was high (1.990 ± 0.091 mg/ml) in methanol extracts of L. aspera and low (0.199 mg/ml) in aqueous extracts. However, the yield of tannins was high (1.713 ± 0.079 mg/ml) in methanol extracts of D. pinnata and low (0.528 ± 0.136 mg/ml) aqueous extracts. The MIC of D. pinnata extracts were found to be 200 mg/ml for both E. coli and E. faecalis. However the L. aspera extracts had a MIC of 100 mg/ml and 200 mg/ml on E. coli and E. faecalis, respectively. Conclusion:: This article demonstrated the potential use of phytochemicals as novel antimicrobial compounds against bacterial infections.

scholarly journals Thrombocytopenia in bacteraemia and association with bacterial species

2018 ◽  
Vol 146 (10) ◽  
pp. 1312-1317 ◽  
Author(s):  
D. Johansson ◽  
M. Rasmussen ◽  
M. Inghammar
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Platelet Count ◽  
Bacterial Infections ◽  
Bacterial Species ◽  
Human Platelets ◽  
Blood Cultures ◽  
Southern Sweden ◽  
Causative Mechanism ◽  
E Coli

AbstractThrombocytopenia is common in patients with invasive bacterial infections. Bacteria can activate platelets, but it is unclear if this affects platelet count. The aim of this study was to examine whether bacteraemia withStaphylococcus aureus, which readily activate human platelets, was more likely to be complicated by thrombocytopenia than bacteraemia withEscherichia coliorStreptococcus pneumoniaewith different abilities to activate platelets.We compared information from 600 adult patients with community-acquired bacteraemia withS. aureus(n= 140),E. coli(n= 420) andS. pneumoniae(n= 40) in Southern Sweden, 2012, linking information on positive blood cultures from microbiological databases and medical charts. The proportion of patients with thrombocytopenia (platelet count <150 × 109/ml) was calculated. Logistic regression was used to estimate the odds ratios (OR) for thrombocytopenia according to bacterial species adjusted for confounders.The proportion of thrombocytopenia was 29% inS. aureus, 28% inE. coliand 20% inS. pneumoniabacteraemia (P= 0.50), corresponding to an OR of 1.2 (95% confidence interval 0.7–1.9) for thrombocytopenia forS. aureusas compared withE. coliorS. pneumoniae, adjusted for confounders.This study indicates that platelet activation by bacteria is not a major causative mechanism in sepsis-associated thrombocytopenia.

scholarly journals Antibiotics Resistance Genes Screening and Comparative Genomics Analysis of Commensal Escherichia coli Isolated from Poultry Farms between China and Sudan

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Sheikheldin A. Abdelgader ◽  
Donglin Shi ◽  
Mianmian Chen ◽  
Lei Zhang ◽  
Hassan M. A. Hejair ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Resistance Genes ◽  
Pcr Amplification ◽  
Antibiotics Resistance ◽  
E Coli ◽  
Resistant Genes ◽  
Sensitivity Pattern ◽  
Antimicrobial Resistance Genes ◽  
Wide Range ◽  
Poultry Farms

Escherichia coli (E. coli) strains, from the gut of animals and humans, harbor wide range of drug resistance genes. A comparative study is conducted on the intestinal E. coli from fecal samples of healthy chicken from China and Sudan in order to monitor the antimicrobial sensitivity pattern. A number of 250 E. coli isolates from chicken farms, including 120 from China and 130 from Sudan, were isolated and identified. All isolates were subjected to susceptibility tests against 10 antibiotics and the distribution of antibiotic resistant genes was confirmed by PCR amplification, involving genes such as ampC, tetA, pKD13, acrA, ermA, ermB, ermC, tetB, mphA, aadA14, aadA1, aac3-1, and aac3- III. Many isolates were found to exhibit resistance against more than one antibiotic. However, the Chinese isolates showed more antibiotics resistance and resistance genes compared to the Sudanese isolates. For better understanding of the multidrug resistance factors, we conducted whole genome analyses of E. coli D107 isolated from China, which revealed that the genome possesses multiple resistance genes including tetracycline, erythromycin, and kanamycin. Furthermore, E. coli D4 isolate from Sudan was more sensitive to antibiotics such as erythromycin, tetracycline, and gentamicin. After analysis by RAST and MAUVE, the two strains showed 89% average nucleotide identity. However, the genomes mostly differed at the number of antibiotics-related genes, as the genome of D107 revealed a considerable number of antibiotics resistance genes such as ermA and mphD which were found to be absent in D4 genome. These outcomes provided confirmation that the poultry farms environment in different countries (China and Sudan) may serve as a potential reservoir of antimicrobial resistance genes and also indicated the evolutionary differences of strains in terms of resistant genes expression.

scholarly journals The Effects of β-Lactam Antibiotics on Surface Modifications of Multidrug-Resistant Escherichia coli: A Multiscale Approach

2019 ◽  
Vol 25 (1) ◽  
pp. 135-150 ◽  
Author(s):  
Samuel C. Uzoechi ◽  
Nehal I. Abu-Lail
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Bacterial Infections ◽  
Treatment Strategies ◽  
Multidrug Resistant ◽  
Multiscale Approach ◽  
Bacterial Cells ◽  
Adhesion Forces ◽  
E Coli ◽  
Resistant Strains

AbstractPossible multidrug-resistant (MDR) mechanisms of four resistant strains of Escherichia coli to a model β-lactam, ampicillin, were investigated using contact angle measurements of wettability, crystal violet assays of permeability, biofilm formation, fluorescence imaging, and nanoscale analyses of dimensions, adherence, and roughness. Upon exposure to ampicillin, one of the resistant strains, E. coli A5, changed its phenotype from elliptical to spherical, maintained its roughness and biofilm formation abilities, decreased its length and surface area, maintained its cell wall integrity, increased its hydrophobicity, and decreased its nanoscale adhesion to a model surface of silicon nitride. Such modifications are suggested to allow these cells to conserve energy during metabolic dormancy. In comparison, resistant strains E. coli D4, A9, and H5 elongated their cells, increased their roughness, increased their nanoscale adhesion forces, became more hydrophilic, and increased their biofilm formation upon exposure to ampicillin. These results suggest that these strains resisted ampicillin through biofilm formation that possibly introduces diffusion limitations to antibiotics. Investigations of how MDR bacterial cells modify their surfaces in response to antibiotics can guide research efforts aimed at designing more effective antibiotics and new treatment strategies for MDR bacterial infections.

scholarly journals Exploring the best possible route of infection of Verotxin producing Escherichia coli in development of experimental gastroenteritis among streptomycin treated murine model

2015 ◽  
Vol 39 (1) ◽  
pp. 53-58
Author(s):  
Fahareen Binta Mosharraf ◽  
Chowdhury Rafiqul Ahsan ◽  
Jamalun Nessa ◽  
Mahmuda Yasmin
Keyword(s):  
Escherichia Coli ◽  
Murine Model ◽  
Bacterial Infections ◽  
Lethal Dose ◽  
Bacterial Strains ◽  
E Coli ◽  
Culture Count ◽  
Alternative Routes ◽  
Academy Of Sciences ◽  
Minimum Lethal Dose

The prevalence of Escherichia coli O157:H7 induced bacteremia generate a critical problem in modern medical therapy for bacterial infections. This study sought to find out the best possible route and dose of E. coli 0157:H7 infection in experimental murine model by periodic stool and blood culture count of relevant bacterial strains. Streptomycin treated mouse model were used for investigating the clinical manifestation exerted by stx1A and stx2A positive E. coli O157:H7 with increasing doses applied through three alternative routes (oral, intramuscular and intraperitoneal). The highest titer of orally added E. coli 0157:H7 among five test doses started showing symptoms at the earliest time and reached moribund condition about 48 hours just before being dead. The oral way of E.coli O157:H7 at the dose of 100 ml suspension containing 1 ´ 109CFU ml-1 was taken as the most potent concentration in producing bacterial fatality and hence was selected as the minimum lethal dose (MLD).Journal of Bangladesh Academy of Sciences, Vol. 39, No. 1, 53-58, 2015

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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