Influence of Extracellular Cellulose and Colanic Acid Production on the Survival of Shiga Toxin–Producing Escherichia coli on Spinach and Lettuce after Chlorine Treatment

2016 ◽  
Vol 79 (4) ◽  
pp. 666-671 ◽  
Author(s):  
CHI-CHING LEE ◽  
JINRU CHEN ◽  
JOSEPH F. FRANK
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Leaf Surface ◽  
Wild Type ◽  
Planktonic Cells ◽  
Extracellular Polymers ◽  
Colanic Acid ◽  
Spinach Leaf ◽  
Strain Pair

ABSTRACT Shiga toxin–producing Escherichia coli (STEC) strains produce extracellular cellulose and colanic acid, which may influence stress tolerance. This study investigates the role of these extracellular polymers on the tolerance of STEC to chlorine treatment after attachment to lettuce and spinach. Four STEC strains, two wild-type cellulose-producing and their cellulose-deficient derivatives, were used. One strain pair produced colanic acid in addition to cellulose. Spinach and lettuce with attached cells were treated with chlorinated water (50 and 150 ppm of free chlorine). The production of the extracellular polymers by the planktonic cells had small, but significant, effects on the survival of the attached pathogen when subjected to chlorine treatment. On the lettuce surface, the colanic acid–producing, cellulose-negative mutant (49d) was most susceptible to the treatment, declining significantly (P < 0.05) in population by 0.9 and 1.4 log units after treatment with 50 and 150 ppm of chlorine, respectively. Chlorine treatment reduced populations of cellulose-deficient cells on the intact spinach surface 1.2 log units more than the wild type when treated with 150 ppm of chlorine (P < 0.05). However, populations of cellulose-producing cells were reduced by 1.5 log units more than their mutant counterparts when the cells also produced colanic acid (P < 0.05). A greater proportion of cells attached to the spinach leaf edge were injured by chlorine treatment compared with attached to the leaf surface. These results indicate that extracellular polymers do not generally increase the ability of STEC to survive chlorine treatment and that any effects on survival are influenced by location of attachment, type of leafy green, and concentration of chlorine.

Role of Cellulose and Colanic Acid in Attachment of Shiga Toxin–Producing Escherichia coli to Lettuce and Spinach in Different Water Hardness Environments

2015 ◽  
Vol 78 (8) ◽  
pp. 1461-1466 ◽  
Author(s):  
CHI-CHING LEE ◽  
JINRU CHEN ◽  
JOSEPH F. FRANK
Keyword(s):  
Escherichia Coli ◽  
Surface Charge ◽  
Shiga Toxin ◽  
Extracellular Polymeric Substances ◽  
Water Hardness ◽  
Wild Type ◽  
Cut Edge ◽  
Colanic Acid ◽  
Spinach Leaf

This study investigated the role of extracellular cellulose production by Shiga toxin–producing Escherichia coli (STEC) on attachment to lettuce and spinach in different water hardness environments. Two cellulose-producing wild-type STEC strains, 19 (O5:H−) and 49 (O103:H2), and their cellulose-deficient derivatives were used. Strain 49 also produced colanic acid as a constituent of its extracellular polymeric substances. Attached cells were determined by plate counts on the surface and cut edge of the leaves after an attachment period of 2 h at 4°C. Hydrophobicity and surface charge of the cells were determined. Strain 49 attached at levels 0.3 and 0.6 log greater to the surface and 0.9 and 0.4 log greater to the cut edges of spinach compared to strain 19 for both wild-type and cellulose-deficient cells (P > 0.05). Cellulose-producing cells attached more to the surface of lettuce but not of spinach than did cellulose-deficient cells. However, more cellulose-deficient cells attached (at levels 0.66 and 0.3 log greater) to the cut edge of lettuce (representing damaged tissue) than did cellulose-proficient cells (P > 0.05). Colanic acid production was associated with cell surfaces of low hydrophobicity. There was a decreasing level of attachment for the colanic acid–producing strain when water hardness increased from 200 to 1,000 pm on lettuce and spinach leaf surfaces, but no effects were seen for other cells. This decreased attachment was associated with a more negative surface charge. Cells that produced colanic acid were less hydrophobic and exhibited greater attachment to the surface and cut edge of spinach when compared to cells that did not produce colanic acid. Attachment of colanic acid–producing cells to leafy green surfaces was enhanced in higher water hardness environments. These data indicate that attachment of E. coli O157:H7 to leafy greens involves multiple mechanisms that are influenced by the type of leafy green, damage to the leaf, and the water hardness environment.

scholarly journals Transposon Insertion in the purL Gene Induces Biofilm Depletion in Escherichia coli ATCC 25922

Pathogens ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 774
Author(s):  
Virginio Cepas ◽  
Victoria Ballén ◽  
Yaiza Gabasa ◽  
Miriam Ramírez ◽  
Yuly López ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
De Novo ◽  
Wild Type ◽  
Planktonic Cells ◽  
E Coli ◽  
Qrt Pcr ◽  
Transposon Insertion ◽  
De Novo Purine Biosynthesis

Current Escherichia coli antibiofilm treatments comprise a combination of antibiotics commonly used against planktonic cells, leading to treatment failure. A better understanding of the genes involved in biofilm formation could facilitate the development of efficient and specific new antibiofilm treatments. A total of 2578 E. coli mutants were generated by transposon insertion, of which 536 were analysed in this study. After sequencing, Tn263 mutant, classified as low biofilm-former (LF) compared to the wild-type (wt) strain (ATCC 25922), showed an interruption in the purL gene, involved in the de novo purine biosynthesis pathway. To elucidate the role of purL in biofilm formation, a knockout was generated showing reduced production of curli fibres, leading to an impaired biofilm formation. These conditions were restored by complementation of the strain or addition of exogenous inosine. Proteomic and transcriptional analyses were performed to characterise the differences caused by purL alterations. Thirteen proteins were altered compared to wt. The corresponding genes were analysed by qRT-PCR not only in the Tn263 and wt, but also in clinical strains with different biofilm activity. Overall, this study suggests that purL is essential for biofilm formation in E. coli and can be considered as a potential antibiofilm target.

scholarly journals Influence of socio-economic status on Shiga toxin-producing Escherichia coli (STEC) infection incidence, risk factors and clinical features

2019 ◽  
Vol 147 ◽  
Author(s):  
N. L. Adams ◽  
L. Byrne ◽  
T. C. Rose ◽  
G. K. Adak ◽  
C. Jenkins ◽  
...  
Keyword(s):  
Risk Factors ◽  
Escherichia Coli ◽  
Shiga Toxin ◽  
Economic Status ◽  
Care Seeking ◽  
Socio Economic Status ◽  
Accident And Emergency ◽  
Incidence Risk ◽  
Potential Risk Factors

Abstract Shiga toxin-producing Escherichia coli (STEC) infection can cause serious illness including haemolytic uraemic syndrome. The role of socio-economic status (SES) in differential clinical presentation and exposure to potential risk factors amongst STEC cases has not previously been reported in England. We conducted an observational study using a dataset of all STEC cases identified in England, 2010–2015. Odds ratios for clinical characteristics of cases and foodborne, waterborne and environmental risk factors were estimated using logistic regression, stratified by SES, adjusting for baseline demographic factors. Incidence was higher in the highest SES group compared to the lowest (RR 1.54, 95% CI 1.19–2.00). Odds of Accident and Emergency attendance (OR 1.35, 95% CI 1.10–1.75) and hospitalisation (OR 1.71, 95% CI 1.36–2.15) because of illness were higher in the most disadvantaged compared to the least, suggesting potential lower ascertainment of milder cases or delayed care-seeking behaviour in disadvantaged groups. Advantaged individuals were significantly more likely to report salad/fruit/vegetable/herb consumption (OR 1.59, 95% CI 1.16–2.17), non-UK or UK travel (OR 1.76, 95% CI 1.40–2.27; OR 1.85, 95% CI 1.35–2.56) and environmental exposures (walking in a paddock, OR 1.82, 95% CI 1.22–2.70; soil contact, OR 1.52, 95% CI 2.13–1.09) suggesting other unmeasured risks, such as person-to-person transmission, could be more important in the most disadvantaged group.

Role of Shiga toxin versus H7 flagellin in enterohaemorrhagic Escherichia coli signalling of human colon epithelium in vivo

2006 ◽  
Vol 8 (5) ◽  
pp. 869-879 ◽  
Author(s):  
Yukiko Miyamoto ◽  
Mitsutoshi Iimura ◽  
James B. Kaper ◽  
Alfredo G. Torres ◽  
Martin F. Kagnoff
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Human Colon ◽  
Enterohaemorrhagic Escherichia Coli

scholarly journals HUS and the case for complement

Blood ◽  
2015 ◽  
Vol 126 (18) ◽  
pp. 2085-2090 ◽  
Author(s):  
Edward M. Conway
Keyword(s):  
Escherichia Coli ◽  
Renal Failure ◽  
Shiga Toxin ◽  
Complement Activation ◽  
Thrombotic Microangiopathy ◽  
Response To Treatment ◽  
Microangiopathic Hemolytic Anemia ◽  
New Knowledge ◽  
Uremic Syndrome

Abstract Hemolytic-uremic syndrome (HUS) is a thrombotic microangiopathy that is characterized by microangiopathic hemolytic anemia, thrombocytopenia, and renal failure. Excess complement activation underlies atypical HUS and is evident in Shiga toxin–induced HUS (STEC-HUS). This Spotlight focuses on new knowledge of the role of Escherichia coli–derived toxins and polyphosphate in modulating complement and coagulation, and how they affect disease progression and response to treatment. Such new insights may impact on current and future choices of therapies for STEC-HUS.

Quantitative Determination of the Role of Lettuce Leaf Structures in Protecting Escherichia coli O157:H7 from Chlorine Disinfection

2001 ◽  
Vol 64 (2) ◽  
pp. 147-151 ◽  
Author(s):  
KAZUE TAKEUCHI ◽  
JOSEPH F. FRANK
Keyword(s):  
Escherichia Coli ◽  
Leaf Surface ◽  
Dead Cell ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Chlorine Disinfection ◽  
Sytox Green ◽  
Tissue Surface ◽  
Confocal Scanning

Viability of Escherichia coli O157:H7 cells on lettuce leaves after 200 mg/liter (200 ppm) chlorine treatment and the role of lettuce leaf structures in protecting cells from chlorine inactivation were evaluated by confocal scanning microscopy (CSLM). Lettuce samples (2 by 2 cm) were inoculated by immersing in a suspension containing 109 CFU/ml of E. coli O157: H7 for 24 ± 1 h at 4°C. Rinsed samples were treated with 200 mg/liter (200 ppm) chlorine for 5 min at 22°C. Viability of E. coli O157:H7 cells was evaluated by CSLM observation of samples stained with Sytox green (dead cell stain) and Alexa 594 conjugated antibody against E. coli O157:H7. Quantitative microscopic observations of viability were made at intact leaf surface, stomata, and damaged tissue. Most E. coli O157:H7 cells (68.3 ± 16.2%) that had penetrated 30 to 40 μm from the damaged tissue surface remained viable after chlorine treatment. Cells on the surface survived least (25.2 ± 15.8% survival), while cells that penetrated 0 to 10 μm from the damaged tissue surface or entered stomata showed intermediate survival (50.8 ± 13.5 and 45.6 ± 9.7% survival, respectively). Viability was associated with the depth at which E. coli O157:H7 cells were in the stomata. Although cells on the leaf surface were mostly inactivated, some viable cells were observed in cracks of cuticle and on the trichome. These results demonstrate the importance of lettuce leaf structures in the protection of E. coli O157:H7 cells from chlorine inactivation.

scholarly journals First-Time Isolation and Characterization of a Bacteriophage Encoding the Shiga Toxin 2c Variant, Which Is Globally Spread in Strains of Escherichia coli O157

2004 ◽  
Vol 72 (12) ◽  
pp. 7030-7039 ◽  
Author(s):  
Eckhard Strauch ◽  
Christoph Schaudinn ◽  
Lothar Beutin
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Phage Lambda ◽  
Wild Type ◽  
Chromosomal Locus ◽  
O157 Strain ◽  
Diagnostic Pcr ◽  
E Coli ◽  
Isolation And Characterization ◽  
K 12

ABSTRACT A bacteriophage encoding the Shiga toxin 2c variant (Stx2c) was isolated from the human Escherichia coli O157 strain CB2851 and shown to form lysogens on the E. coli K-12 laboratory strains C600 and MG1655. Production of Stx2c was found in the wild-type E. coli O157 strain and the K-12 lysogens and was inducible by growing bacteria in the presence of ciprofloxacin. Phage 2851 is the first reported viable bacteriophage which carries an stx 2c gene. Electron micrographs of phage 2851 showed particles with elongated hexagonal heads and long flexible tails resembling phage lambda. Sequence analysis of an 8.4-kb region flanking the stx 2c gene and other genetic elements revealed a mosaic gene structure, as found in other Stx phages. Phage 2851 showed lysis of E. coli K-12 strains lysogenic for Stx phages encoding Stx1 (H19), Stx2 (933W), Stx (7888), and Stx1c (6220) but showed superinfection immunity with phage lambda, presumably originating from the similarity of the cI repressor proteins of both phages. Apparently, phage 2851 integrates at a different chromosomal locus than Stx2 phage 933W and Stx1 phage H19 in E. coli, explaining why Stx2c is often found in combination with Stx1 or Stx2 in E. coli O157 strains. Diagnostic PCR was performed to determine gene sequences specific for phage 2851 in wild-type E. coli O157 strains producing Stx2c. The phage 2851 q and o genes were frequently detected in Stx2c-producing E. coli O157 strains, indicating that phages related to 2851 are associated with Stx2c production in strains of E. coli O157 that were isolated in different locations and time periods.

scholarly journals Fimbria-Encoding GeneyadCHas a Pleiotropic Effect on Several Biological Characteristics and Plays a Role in Avian Pathogenic Escherichia coli Pathogenicity

2015 ◽  
Vol 84 (1) ◽  
pp. 187-193 ◽  
Author(s):  
Renu Verma ◽  
Thaís Cabrera Galvão Rojas ◽  
Renato Pariz Maluta ◽  
Janaína Luisa Leite ◽  
Livia Pilatti Mendes da Silva ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Soft Agar ◽  
Pleiotropic Effect ◽  
Biological Characteristics ◽  
Wild Type ◽  
Content Type ◽  
Pathogenic Escherichia Coli

The extraintestinal pathogen termed avian pathogenicEscherichia coli(APEC) is known to cause colibacillosis in chickens. The molecular basis of APEC pathogenesis is not fully elucidated yet. In this work, we deleted a component of the Yad gene cluster (yadC) in order to understand the role of Yad in the pathogenicity of the APEC strain SCI-07.In vitro, the transcription level ofyadCwas upregulated at 41°C and downregulated at 22°C. TheyadCexpressionin vivowas more pronounced in lungs than in spleen, suggesting a role in the early steps of the infection. Chicks infected with the wild-type and mutant strains presented, respectively, 80% and 50% mortality rates. The ΔyadCstrain presented a slightly decreased ability to adhere to HeLa cells with or without thed-mannose analog compared with the wild type. Real-time PCR (RT-PCR) assays showed thatfimHwas downregulated (P< 0.05) andcsgAandecpAwere slightly upregulated in the mutant strain, showing thatyadCmodulates expression of other fimbriae. Bacterial internalization studies showed that the ΔyadCstrain had a lower number of intracellular bacteria recovered from Hep-2 cells and HD11 cells than the wild-type strain (P< 0.05). Motility assays in soft agar demonstrated that the ΔyadCstrain was less motile than the wild type (P< 0.01). Curiously, flagellum-associated genes were not dramatically downregulated in the ΔyadCstrain. Taken together, the results show that the fimbrial adhesin Yad contributes to the pathogenicity and modulates different biological characteristics of the APEC strain SCI-07.

scholarly journals Interaction of Enteropathogenic and Shiga Toxin-Producing Escherichia coli and Porcine Intestinal Mucosa: Role of Intimin and Tir in Adherence

2005 ◽  
Vol 73 (9) ◽  
pp. 6005-6016 ◽  
Author(s):  
Francis Girard ◽  
Isabelle Batisson ◽  
Gad M. Frankel ◽  
Josée Harel ◽  
John M. Fairbrother
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Actin Polymerization ◽  
Animal Species ◽  
Ex Vivo ◽  
Epec Strain ◽  
E Coli ◽  
In Vitro Organ Culture

ABSTRACT The ileal in vitro organ culture (IVOC) model using tissues originating from colostrum-deprived newborn piglets has proven to be an effective way to study the attaching and effacing (A/E) phenotype of porcine enteropathogenic Escherichia coli (EPEC) ex vivo. The aim of this study was to investigate the role of intimin subtype and Tir in the adherence of EPEC and Shiga-toxin-producing E. coli (STEC), isolated from different animal species, to porcine intestinal IVOC. Moreover, the role of intimin in Tir-independent adherence of the human EPEC strain E2348/69 was investigated using intimin and Tir-deficient derivatives. Our results demonstrated that A/E E. coli strains (AEEC) from various animal species and humans induce the A/E phenotype in porcine ileal IVOC and that intimin subtype influences intestinal adherence and tropism of AEEC strains. We also showed that a tir mutant of EPEC strain E2348/69 demonstrates close adherence to the epithelial cells of porcine ileal IVOC segments, with microvillous effacement but with no evidence of actin polymerization or pedestal formation, and that intimin seems to be involved in this phenotype. Overall, this study provides further evidence for the existence of one or more host-cell-encoded intimin receptor(s) in the pig gut.

Sign in / Sign up

Export Citation Format

Share Document