scholarly journals Impact of Different Parameters upon the Production of Virulence Factors in Escherichia coli Strains Isolated from Marine Water

2020 ◽  
Vol 10 (6) ◽  
pp. 7049-7060
Keyword(s):  
Escherichia Coli ◽  
Virulence Factors ◽  
Inhibitory Effect ◽  
Environmental Stressors ◽  
The Black Sea ◽  
Anaerobic Incubation ◽  
E Coli ◽  
Ph Values ◽  
Black Sea Coast ◽  
Aerobic And Anaerobic

This study aimed to look into the expression of 10 virulence factors (VF) in 100 Escherichia coli strains harvested from the Black Sea Coast. E. coli strains were grown under different conditions, simulating various environmental stressors. The VF production [esculinase, amylase, pore-forming enzymes (hemolysin - spot and CAMP-like hemolysis; lipase; lecithinase)], lysine-decarboxylase, proteases (caseinase, gelatinase) and DNase was investigated at variable temperatures (4°C, 22°C, 37°C, 44°C and 56°C), NaCl (from 0 to 10%) and glucose concentrations (1.5% and 3%), different pH values (5.0, 7.2 and 9.6) and also in aerobic or anaerobic incubation conditions. The investigation of E. coli strains unraveled their ability to grow at 22°C, 37°C, 44°C, regardless of the salinity, pH, and glucose concentration, both in aerobic and anaerobic incubation conditions. The VF were better expressed at 37°C, followed by 22°C, especially siderophores, amylase, and caseinase production. The expression of different VF was variable at a certain salinity, i.e., at 0% NaCl, only amylase and siderophores production was observed. At 2% and 3%, the amylase was better expressed. The best expression of siderophores and caseinase was at 6% NaCl. At higher salinity, the expression of VF started to decrease. The amylase and caseinase were better expressed at pH 9.6 and siderophores at pH 7.2. Higher glucose concentrations (3%) proved to have an inhibitory effect on amylase expression and caseinase. The aerobic/anaerobic incubation conditions exhibited no significant differences in the VF expression. In conclusion, these outcomes reveal the ability of enterobacterial aquatic strains to survive in the presence of different stressors and maintain the expression of potential VF expression even in extreme environmental conditions.

scholarly journals Growth of cell wall-defective variants of Escherichia coli: comparison of aerobic and anaerobic induction frequencies

1977 ◽  
Vol 6 (2) ◽  
pp. 166-171
Author(s):  
T W Huber ◽  
A W Brinkley
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
High Frequency ◽  
Anaerobic Incubation ◽  
Anaerobic Conditions ◽  
Group Iii ◽  
E Coli ◽  
Induction Frequency ◽  
Group I ◽  
Aerobic And Anaerobic

A method for quantitating the conversion of Escherichia coli to colony-forming, cell wall-defective (CWD) bacteria has been developed. The induction frequency, i.e., the percentage of the population recovered as CWD colonies was determined for 20 randomly selected clinical isolates of E. coli under aerobic and anaerobic incubation conditions. Penicillin (1,000 U/ML) was the inducing agent. The 20 strains segregated into three groups. Group I organisms produced CWD colonies with high frequency both aerobically and anaerobically. Grout II organisms showed a much higher induction frequency anaerobically than aerobically. Group III organisms were poor inducers. Thirty percent of the strains were group I, 50% were group II, and 20% were group III organisms. These data indicate that anaerobic conditions enhance the induction and growth of CWD E. coli in the research laboratory and suggest that anaerobic incubation may be important in recovery of medically significant CWD bacteria.

Development of Nano-ZnO Coated Food Packaging Film and its Inhibitory Effect on Escherichia coli In Vitro and in Actual Tests

2010 ◽  
Vol 152-153 ◽  
pp. 489-492 ◽  
Author(s):  
Wei Li Li ◽  
Xi Hong Li ◽  
Pei Pei Zhang ◽  
Ya Ge Xing
Keyword(s):  
Escherichia Coli ◽  
Food Packaging ◽  
Inhibitory Effect ◽  
Test Results ◽  
Nano Zno ◽  
E Coli ◽  
Ph Values ◽  
Coated Film ◽  
Actual Test

In this study, we investigated antibacterial activity of zinc oxide (ZnO) nanoparticles coated on polyvinyl chloride (PVC) films against Escherichia. coli both in vitro and in actual test. Results showed that the nano-ZnO coated films displayed excellent inhibition effects on the growth of E. coli and the nano-ZnO particular was contributed to the bactericidal ability. The more amounts of the ZnO particulars the film coated, the greater inhibitory effect it exhibited. The disinfection efficiency with ZnO film is relatively constant at pH values in the range of 4.5 to 8.0. In the actual test, the number of E. coli cells from cut apple stored in a ZnO-coated bag in the dark decreased from 8.72 to 6.3 log CFU/ml after 1 day, while that of an same bag irradiated with light decreased from 8.72 to 3.5 log CFU/ml after 2 days of storage. The results reveal that nano-ZnO coated film has a good promise to make antimicrobial packaging again E. coli and reduce the risks of microbial growth on fresh-cut produce.

scholarly journals The AIDA Autotransporter System Is Associated with F18 and Stx2e in Escherichia coli Isolates from Pigs Diagnosed with Edema Disease and Postweaning Diarrhea

2001 ◽  
Vol 8 (1) ◽  
pp. 143-149 ◽  
Author(s):  
Ulla Niewerth ◽  
Andreas Frey ◽  
Thomas Voss ◽  
Chantal Le Bouguénec ◽  
Georg Baljer ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Western Blot ◽  
Virulence Factors ◽  
Rapid Screening ◽  
Edema Disease ◽  
E Coli ◽  
Large Numbers ◽  
High Prevalence ◽  
Pcr Method ◽  
Postweaning Diarrhea

ABSTRACT Pathogenic Escherichia coli strains are known to cause edema disease (ED) and postweaning diarrhea (PWD) in piglets. Although the exact mechanisms of pathogenicity that lead to ED-PWD remain to be elucidated, E. coli-borne Shiga-like toxin and adhesion-mediating virulence factors such as F18 adhesin or F4 fimbriae are believed to play a central role in ED-PWD. In light of these observations we investigated whether another E. coliadhesin, the plasmid-encoded AIDA (adhesin involved in diffuse adherence) might also be present in ED-PWD-causing E. coli isolates. For rapid screening for the AIDA system in large numbers of isolates, a multiplex PCR method along with a duplex Western blot procedure was developed. When screening 104 strains obtained from pigs with or without ED-PWD, we observed a high prevalence of the AIDA operon in porcine E. coli isolates, with over 25% of all strains being AIDA positive, and we could demonstrate a significant association of the intact AIDA gene (orfB) with ED-PWD, while defects in orfB were associated with the absence of disease. Although our data hint toward a contribution of AIDA to ED-PWD, further studies will be necessary since the presence of the AIDA genes was also associated with the presence of the Shiga-like toxin and F18 adhesin genes, two reported virulence factors for ED-PWD.

scholarly journals The Repeat-In-Toxin Family Member TosA Mediates Adherence of Uropathogenic Escherichia coli and Survival during Bacteremia

2011 ◽  
Vol 80 (2) ◽  
pp. 493-505 ◽  
Author(s):  
Patrick D. Vigil ◽  
Travis J. Wiles ◽  
Michael D. Engstrom ◽  
Lev Prasov ◽  
Matthew A. Mulvey ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Virulence Factors ◽  
Upper Urinary Tract ◽  
Host Cells ◽  
Content Type ◽  
E Coli ◽  
Wide Range ◽  
Novel Target ◽  
Tract Infections

ABSTRACTUropathogenicEscherichia coli(UPEC) is responsible for the majority of uncomplicated urinary tract infections (UTI) and represents the most common bacterial infection in adults. UPEC utilizes a wide range of virulence factors to colonize the host, including the novel repeat-in-toxin (RTX) protein TosA, which is specifically expressed in the host urinary tract and contributes significantly to the virulence and survival of UPEC.tosA, found in strains within the B2 phylogenetic subgroup ofE. coli, serves as a marker for strains that also contain a large number of well-characterized UPEC virulence factors. The presence oftosAin anE. coliisolate predicts successful colonization of the murine model of ascending UTI, regardless of the source of the isolate. Here, a detailed analysis of the function oftosArevealed that this gene is transcriptionally linked to genes encoding a conserved type 1 secretion system similar to other RTX family members. TosA localized to the cell surface and was found to mediate (i) adherence to host cells derived from the upper urinary tract and (ii) survival in disseminated infections and (iii) to enhance lethality during sepsis (as assessed in two different animal models of infection). An experimental vaccine, using purified TosA, protected vaccinated animals against urosepsis. From this work, it was concluded that TosA belongs to a novel group of RTX proteins that mediate adherence and host damage during UTI and urosepsis and could be a novel target for the development of therapeutics to treat ascending UTIs.

scholarly journals 2609. Escherichia coli Clonal Lineages and Virulence Factors Predict Fecal Colonization within Households

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S907-S907
Author(s):  
Teresa C Fox ◽  
Paul Thuras ◽  
Connie Clabots ◽  
Stephen Porter ◽  
James R Johnson
Keyword(s):  
Escherichia Coli ◽  
Clinical Isolate ◽  
Virulence Factors ◽  
Outcome Variable ◽  
E Coli ◽  
Wilcoxon Rank Sum Test ◽  
Colonization Patterns ◽  
Stool Samples ◽  
Colonization Factors ◽  
Colonization Behavior

Abstract Background Extraintestinal Escherichia coli infections are an ever-growing threat, to which specific clonal lineages and virulence factors contribute disproportionately. Despite the gut being the main reservoir for such E. coli strains, relationships between clonal lineages, virulence factors, and fecal colonization patterns are poorly understood. Accordingly, we defined E. coli fecal colonization patterns within households (HHs) and assessed specific lineages and virulence genes (VGs) as predictors of colonization behaviors. Methods Veterans with an E. coli clinical isolate (n = 22: 11 fluoroquinoline [FQ]-resistant, 11 FQ-susceptible) and their HH members provided stool samples on 2–6 occasions each. Stools were screened for total and FQ-resistant E. coli. Distinct E. coli strains were resolved by genomic profiling of 10 colonies/sample. Strains underwent molecular lineage identification, VG detection, and comparison with the veteran’s clinical isolate. Clonal lineages and VGs were assessed (Wilcoxon rank-sum test) as predictors of strains’ (i) predominance within the fecal sample, (ii) persistence across serial fecal samples, (iii) within-HH strain sharing, and (iv) overall within-HH colonization prevalence. Results From the 22 veterans and 46 HH members (27 humans, 19 pets) we recovered 139 unique-by-household fecal E. coli strains. Sixty-four traits were evaluated (16 clonal lineages, 48 VGs). Of these, 44 exhibited n ≥ 5, so could be analyzed statistically. Among these 44 traits, the proportion significantly associated with ≥ 1 outcome variable was 5/6 (83%) for clonal lineages and 18/38 (47%) for VGs. Additionally, fecal strains that matched the veteran’s clinical isolate exhibited significantly greater sharing, persistence, and overall colonization. Conclusion The studied E. coli traits – known for their associations with clinical infections –here were significantly associated with within-HH colonization behavior. These findings support that “virulence factors” may be regarded also (or perhaps best) as “colonization factors,” and “virulent lineages” as “colonizing lineages.” This suggests the possibility that future interventions that disrupt colonization behavior also could prevent E. coli infections. Disclosures All authors: No reported disclosures.

A Bacteriological Survey of Raw Ground Beef1

1977 ◽  
Vol 40 (11) ◽  
pp. 790-794 ◽  
Author(s):  
JAMES F. FOSTER ◽  
JAMES L. FOWLER ◽  
WARREN C. LADIGES
Keyword(s):  
Escherichia Coli ◽  
Microbiological Quality ◽  
Retail Store ◽  
Most Probable Number ◽  
Probable Number ◽  
E Coli ◽  
Fecal Streptococci ◽  
Plate Counts ◽  
Aerobic And Anaerobic

The microbiological quality of 150 units of raw ground beef obtained from a local retail store was determined. The range of aerobic plate counts was from 6.9 × 104 to 8.3 × 107/g. By using the most probable number method 96.7% of the 150 units were positive for coliforms, 94.7% for Escherichia coli and 61.3% for Staphylococcus aureus. By the plate methods, 99.3% of the units were positive for fecal streptococci and 56% were positive for Clostridium perfringens. No salmonellae were isolated. Aerobic and anaerobic organisms were isolated and identified. E. coli was the most frequently isolated aerobe followed by organisms in the Klebsiella-Enterobacter group. Among the anaerobic isolates, C. perfringens was the organism most frequently encountered.

scholarly journals Genomic Avenue to Avian Colisepticemia

mBio ◽  
2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Sagi Huja ◽  
Yaara Oren ◽  
Eva Trost ◽  
Elzbieta Brzuszkiewicz ◽  
Dvora Biran ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Genetic Analysis ◽  
Virulence Factors ◽  
Iron Uptake ◽  
Secretion System ◽  
Economic Losses ◽  
Content Type ◽  
E Coli ◽  
Type 3 Secretion System ◽  
Type 3

ABSTRACTHere we present an extensive genomic and genetic analysis of Escherichia coli strains of serotype O78 that represent the major cause of avian colisepticemia, an invasive infection caused by avian pathogenicEscherichia coli(APEC) strains. It is associated with high mortality and morbidity, resulting in significant economic consequences for the poultry industry. To understand the genetic basis of the virulence of avian septicemic E. coli, we sequenced the entire genome of a clinical isolate of serotype O78—O78:H19 ST88 isolate 789 (O78-9)—and compared it with three publicly available APEC O78 sequences and one complete genome of APEC serotype O1 strain. Although there was a large variability in genome content between the APEC strains, several genes were conserved, which are potentially critical for colisepticemia. Some of these genes are present in multiple copies per genome or code for gene products with overlapping function, signifying their importance. A systematic deletion of each of these virulence-related genes identified three systems that are conserved in all septicemic strains examined and are critical for serum survival, a prerequisite for septicemia. These are the plasmid-encoded protein, the defective ETT2 (E. colitype 3 secretion system 2) type 3 secretion system ETT2sepsis, and iron uptake systems. Strain O78-9 is the only APEC O78 strain that also carried the regulon coding for yersiniabactin, the iron binding system of theYersiniahigh-pathogenicity island. Interestingly, this system is the only one that cannot be complemented by other iron uptake systems under iron limitation and in serum.IMPORTANCEAvian colisepticemia is a severe systemic disease of birds causing high morbidity and mortality and resulting in severe economic losses. The bacteria associated with avian colisepticemia are highly antibiotic resistant, making antibiotic treatment ineffective, and there is no effective vaccine due to the multitude of serotypes involved. To understand the disease and work out strategies to combat it, we performed an extensive genomic and genetic analysis of Escherichia coli strains of serotype O78, the major cause of the disease. We identified several potential virulence factors, conserved in all the colisepticemic strains examined, and determined their contribution to growth in serum, an absolute requirement for septicemia. These findings raise the possibility that specific vaccines or drugs can be developed against these critical virulence factors to help combat this economically important disease.

scholarly journals Relative Fecal Abundance of Extended-Spectrum-β-Lactamase-Producing Escherichia coli Strains and Their Occurrence in Urinary Tract Infections in Women

2013 ◽  
Vol 57 (9) ◽  
pp. 4512-4517 ◽  
Author(s):  
Etienne Ruppé ◽  
Brandusa Lixandru ◽  
Radu Cojocaru ◽  
Çağrı Büke ◽  
Elisabeth Paramythiotou ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Virulence Factors ◽  
Urinary Tract Infections ◽  
Predictive Values ◽  
Content Type ◽  
Extended Spectrum Beta Lactamase ◽  
E Coli ◽  
Extended Spectrum ◽  
Tract Infections

ABSTRACTExtended-spectrum-beta-lactamase (ESBL)-producingEscherichia coli(ESBLE. coli) strains are of major concern because few antibiotics remain active against these bacteria. We investigated the association between the fecal relative abundance (RA) of ESBL-producingE. coli(ESBL-RA) and the occurrence of ESBLE. coliurinary tract infections (UTIs). The first stool samples passed after suspicion of UTI from 310 women with subsequently confirmedE. coliUTIs were sampled and tested for ESBL-RA by culture on selective agar. Predictive values of ESBL-RA for ESBLE. coliUTI were analyzed for women who were not exposed to antibiotics when the stool was passed. ESBLE. coliisolates were characterized for ESBL type, phylogroup, relatedness, and virulence factors. The prevalence of ESBLE. colifecal carriage was 20.3%, with ESBLE. coliUTIs being present in 12.3% of the women. The mean ESBL-RA (95% confidence interval [CI]) was 13-fold higher in women exposed to antibiotics at the time of sampling than in those not exposed (14.3% [range, 5.6% to 36.9%] versus 1.1% [range, 0.32% to 3.6%], respectively;P< 0.001) and 18-fold higher in women with ESBLE. coliUTI than in those with anotherE. coliUTI (10.0% [range, 0.54% to 100%] versus 0.56% [range, 0.15% to 2.1%[, respectively;P< 0.05). An ESBL-RA of <0.1% was 100% predictive of a non-ESBLE. coliUTI. ESBL type, phylogroup, relatedness, and virulence factors were not found to be associated with ESBL-RA. In conclusion, ESBL-RA was linked to the occurrence of ESBLE. coliUTI in women who were not exposed to antibiotics and who had the same clone ofE. coliin urine samples and fecal samples. Especially, a low ESBL-RA appeared to be associated with a low risk of ESBLE. coliinfection.

scholarly journals MazF-Mediated Cell Death in Escherichia coli: a Point of No Return

2004 ◽  
Vol 186 (24) ◽  
pp. 8295-8300 ◽  
Author(s):  
Shahar Amitai ◽  
Yussuf Yassin ◽  
Hanna Engelberg-Kulka
Keyword(s):  
Escherichia Coli ◽  
Cell Death ◽  
Programmed Cell Death ◽  
Inhibitory Effect ◽  
Luria Bertani ◽  
E Coli ◽  
Ectopic Overexpression ◽  
Point Of No Return ◽  
The Rich ◽  
Overexpression System

ABSTRACT mazEF is a stress-induced toxin-antitoxin module, located on the chromosome of Escherichia coli, that we have previously described to be responsible for programmed cell death in E. coli. mazF specifies a stable toxin, and mazE specifies a labile antitoxin. Recently, it was reported that inhibition of translation and cell growth by ectopic overexpression of the toxin MazF can be reversed by the action of the antitoxin MazE ectopically overexpressed at a later time. Based on these results, it was suggested that rather than inducing cell death, mazF induces a state of reversible bacteriostasis (K. Pederson, S. K. Christensen, and K. Gerdes, Mol. Microbiol. 45:501-510, 2002). Using a similar ectopic overexpression system, we show here that overexpression of MazE could reverse MazF lethality only over a short window of time. The size of that window depended on the nature of the medium in which MazF was overexpressed. Thus, we found “a point of no return,” which occurred sooner in minimal M9 medium than it did in the rich Luria-Bertani medium. We also describe a state in which the effect of MazF on translation could be separated from its effect on cell death: MazE overproduction could completely reverse the inhibitory effect of MazF on translation, while not affecting the bacteriocidic effect of MazF at all. Our results reported here support our view that the mazEF module mediates cell death and is part of a programmed cell death network.

scholarly journals Role of Escherichia coli O157:H7 Virulence Factors in Colonization at the Bovine Terminal Rectal Mucosa

2006 ◽  
Vol 74 (8) ◽  
pp. 4685-4693 ◽  
Author(s):  
Haiqing Sheng ◽  
Ji Youn Lim ◽  
Hannah J. Knecht ◽  
Jie Li ◽  
Carolyn J. Hovde
Keyword(s):  
Escherichia Coli ◽  
Virulence Factors ◽  
Clinical Manifestations ◽  
Rectal Mucosa ◽  
Wild Type ◽  
E Coli ◽  
Healthy Cattle ◽  
Life Threatening ◽  
K 12 ◽  
The Impact

ABSTRACT The human pathogen Escherichia coli O157:H7 causes hemorrhagic colitis and life-threatening sequelae and transiently colonizes healthy cattle at the terminal rectal mucosa. This study analyzed virulence factors important for the clinical manifestations of human E. coli O157:H7 infection for their contribution to the persistence of E. coli in cattle. The colonizing ability of E. coli O157:H7 was compared with those of nonpathogenic E. coli K-12 and isogenic deletion mutants missing Shiga toxin (Stx), the adhesin intimin, its receptor Tir, hemolysin, or the ∼92-kb pO157. Fully ruminant steers received a single rectal application of one E. coli strain so that effects of mucosal attachment and survival at the terminal rectum could be measured without the impact of bacterial passage through the entire gastrointestinal tract. Colonization was monitored by sensitive recto-anal junction mucosal swab culture. Nonpathogenic E. coli K-12 did not colonize as well as E. coli O157:H7 at the bovine terminal rectal mucosa. The E. coli O157:H7 best able to persist had intimin, Tir, and the pO157. Strains missing even one of these factors were recovered in lower numbers and were cleared faster than the wild type. In contrast, E. coli O157:H7 strains that were missing Stx or hemolysin colonized like the wild type. For these three strains, the number of bacteria increased between days 1 and 4 postapplication and then decreased slowly. In contrast, the numbers of noncolonizing strains (K-12, Δtir, and Δeae) decreased from the day of application. These patterns consistently predicted long-term colonization or clearance of the bacteria from the bovine terminal rectal mucosa.

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