Colicinogeny among Escherichia coli Serotypes, Including O157:H7, Representing Four Closely Related Diarrheagenic Clones

1998 ◽  
Vol 61 (11) ◽  
pp. 1431-1438 ◽  
Author(s):  
SHELTON E. MURINDA ◽  
SHU-MIN LIU ◽  
ROBERT F. ROBERTS ◽  
RICHARD A. WILSON
Keyword(s):  
Escherichia Coli ◽  
Toxin Production ◽  
Coli Strain ◽  
The Other ◽  
E Coli ◽  
Diarrheagenic Escherichia Coli ◽  
Reference Set ◽  
Almost All ◽  
Luria Agar

Twenty-seven diarrheagenic Escherichia coli (DEC) strains from five closely related, genetically distinct clones (DEC 3, 4, 8, 9, and 10), representing serotypes commonly associated with Shiga-like toxin production, i.e., 015:H−, 026:(H11, H−), 0111:(H8, H11, H−), and O157:H7, were evaluated for colicinogeny on Luria agar or Luria agar containing 0.25 μg/ml mitomycin C to induce colicin production. Ten (37%) of the DEC strains tested were colicinogenic. One of 11 serotype O157:H7 strains, DEC strain 4E, produced a colicin identified as Col D. DEC strains 8B, 9D, and 10B produced Col E1, whereas DEC strain 10A produced Col E2. DEC strains 8A, 8E, 10C, 10E, and 10F produced “untypable” colicins that killed almost all Pugsley Colicin Reference Set strains and the other DEC strains tested. To aid with further characterization of the colicins, plasmids extracted from each colicin-producing (Col+) DEC strain were used to transform E. coli strain DH5α. All Col+ DH5α transformants contained one plasmid ranging in size from 1.3 to 10 kb. Some transformants were stable colicin producers whereas others were unstable. The inhibitory activity and colicin sensitivity and insensitivity profiles of the Col+ transformants were similar to those of the corresponding Col+ donor DEC strains. It appears that the untypable colicins are novel and, thus, warrant further study. Colicin production by some of the DEC strains evaluated partly explains why they were insensitive to standard colicins in a previous study.

scholarly journals Characterization of Diarrheagenic Escherichia Coli Strains Isolated from Slaughtered Sheep in México

2021 ◽  
Author(s):  
Jorge Acosta-Dibarrat ◽  
Edgar Enriquez-Gómez ◽  
Martín Talavera-Rojas ◽  
Edgardo Soriano-Vargas ◽  
Armando Navarro ◽  
...  
Keyword(s):  
Public Health ◽  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Central Region ◽  
Shiga Toxin ◽  
E Coli ◽  
Diarrheagenic Escherichia Coli ◽  
Food Borne ◽  
Almost All

Abstract Sheep represent one of the main reservoirs of diarrheagenic Escherichia coli; this microorganism is an etiological agent of food-borne diseases, therefore, this work aimed to identify and characterize the principal pathotypes of diarrheagenic E. coli obtained through rectal swabs and samples from sheep carcasses slaughtered in an abattoir at the central region of Mexico. The isolates were subjected to bacteriological identification, serotyping; phylogenetic classification; detection for virulence factors, and antimicrobial sensibility. A total of 90 E. coli isolates were obtained, diarrheagenic serotypes with health public relevance were found: O76:H19 (5), O146:H21 (3), O91:H10 (2), O6:NM (1), and O8:NM (1). According to pathotype, 47.7% of total isolates were Shiga toxin-producing E. coli, while 3.3% were enteropathogenic, 2.2% enterotoxigenic, and 1.1% enteroinvasive E. coli; the remaining isolates did not express the genes used to assign them to some pathotype. Regarding the Shiga toxin subtypes, 31/43 (72.09%) were cataloged as stx1c, 11/43 (25.5%), stx1a- stx1c and 1/43 (2.3%) stx1a- stx1d; while for stx2 it was possible identify stx2g 4/7(57.14%), stx2b 1/7 (14.7%) and stx2b-stx2g 2/7 (28.5%). Almost all pathotypes (91–100%) belonged to phylogroup B1. Furthermore, it was observed that the 90 isolates showed an antimicrobial resistance of 100% to nitrofurantoin, followed by ampicillin, tetracycline, and trimethoprim-sulfamethoxazole. These results highlight the importance of diarrheagenic E. coli as a potential risk for public health during the slaughtering process.

scholarly journals Genomic and Proteomic Characterization of the Extended-Spectrum β-Lactamase (ESBL)-Producing Escherichia coli Strain CCUG 73778: A Virulent, Nosocomial Outbreak Strain

2020 ◽  
Vol 8 (6) ◽  
pp. 893 ◽  
Author(s):  
Daniel Jaén-Luchoro ◽  
Antonio Busquets ◽  
Roger Karlsson ◽  
Francisco Salvà-Serra ◽  
Christina Åhrén ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Coli Strain ◽  
University Hospital ◽  
Hospital Environment ◽  
Resistance Factors ◽  
E Coli ◽  
Extended Spectrum ◽  
Liquid Chromatography Tandem Mass

Escherichia coli strain CCUG 78773 is a virulent extended-spectrum β-lactamase (ESBL)-producing ST131-O25b type strain isolated during an outbreak at a regional university hospital. The complete and closed genome sequence, comprising one chromosome (5,076,638 bp) and six plasmids (1718–161,372 bp), is presented. Characterization of the genomic features detected the presence of 59 potential antibiotic resistance factors, including three prevalent β-lactamases. Several virulence associated elements were determined, mainly related with adherence, invasion, biofilm formation and antiphagocytosis. Twenty-eight putative type II toxin-antitoxin systems were found. The plasmids were characterized, through in silico analyses, confirming the two β-lactamase-encoding plasmids to be conjugative, while the remaining plasmids were mobilizable. BLAST analysis of the plasmid sequences showed high similarity with plasmids in E. coli from around the world. Expression of many of the described virulence and AMR factors was confirmed by proteomic analyses, using bottom-up, liquid chromatography-tandem mass spectrometry (LC-MS/MS). The detailed characterization of E. coli strain CCUG 78773 provides a reference for the relevance of genetic elements, as well as the characterization of antibiotic resistance and the spread of bacteria harboring ESBL genes in the hospital environment.

scholarly journals Cloning and characterization of the iron uptake gene iutA from avian Escherichia coli

2008 ◽  
Vol 51 (3) ◽  
pp. 473-482 ◽  
Author(s):  
Dorismey Vieira Tokano ◽  
Marisa Emiko Kawaichi ◽  
Emerson José Venâncio ◽  
Marilda Carlos Vidotto
Keyword(s):  
Escherichia Coli ◽  
Biological Activity ◽  
Iron Uptake ◽  
Expression Vector ◽  
Iron Acquisition ◽  
Coli Strain ◽  
High Yield ◽  
High Similarity ◽  
E Coli

The aim of this work was to isolate, clone and characterize the iron uptake gene iutA from avian pathogenic E. coli (APEC). The iutA gene was isolated from the strain APEC 9, serotype O2:H9, which was cloned in the expression vector pET101/D-TOPO. The gene of 2.2 Kb was sequenced (AY602767, which showed high similarity to the iutA gene from three plasmids, two from APEC, pAPEC-02-ColV (AY545598.4) and pTJ100 (AY553855.1), and one from a human invasive E. coli strain, the pColV K30. The recombinant protein IutA was over expressed in E. coli BL21(DE-3) and was solubilized with urea and purified by Ni-NTA column. This method produced a relatively high yield of r-IutA of approximately 74kDa, which was used to produce the antibody anti-IutA. This anti-IutA reacted with the protein r-IutA and native IutA of APEC 9, as demonstrated by Western blot, showing that the r-IutA conserved epitopes and its antigenicity was preserved. The anti-IutA IgY was able to inhibit the IutA biological activity, inhibiting the sensitivity to cloacin DF13 of APEC9. However, it did not inhibit the growth of APEC9 in M9 and did not protect the chickens inoculated with the APEC, suggesting that the APEC possessed another iron acquisition mechanism distinct of aerobactin.

scholarly journals Molecular and phenotypic characterization of diarrheagenic Escherichia coli isolated from groundwater in rural areas in southern Brazil

2019 ◽  
Vol 17 (4) ◽  
pp. 597-608
Author(s):  
Caroline Rodrigues da Silva ◽  
Matheus Silva Sanches ◽  
Kawana Hiromori Macedo ◽  
Angélica Marim Lopes Dambrozio ◽  
Sergio Paulo Dejato da Rocha ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Rural Areas ◽  
Microbiological Quality ◽  
Vero Cells ◽  
Phenotypic Characterization ◽  
Human Consumption ◽  
E Coli ◽  
Diarrheagenic Escherichia Coli ◽  
Quality Of Water

Abstract Water-borne diseases like diarrheagenic Escherichia coli (DEC)-induced gastroenteritis are major public health problems in developing countries. In this study, the microbiological quality of water from mines and shallow wells was analyzed for human consumption. Genotypic and phenotypic characterization of DEC strains was performed. A total of 210 water samples was analyzed, of which 153 (72.9%) contained total coliforms and 96 (45.7%) E. coli. Of the E. coli isolates, 27 (28.1%) contained DEC genes. The DEC isolates included 48.1% Shiga toxin-producing E. coli (STEC), 29.6% enteroaggregative E. coli (EAEC), 14.9% enteropathogenic E. coli (EPEC), 3.7% enterotoxigenic E. coli (ETEC), and 3.7% enteroinvasive E. coli (EIEC). All the STECs had cytotoxic effects on Vero cells and 14.8% of the DEC isolates were resistant to at least one of the antibiotics tested. All DEC formed biofilms and 92.6% adhered to HEp-2 cells with a prevalence of aggregative adhesion (74%). We identified 25 different serotypes. One EPEC isolate was serotype O44037:H7, reported for the first time in Brazil. Phylogenetically, 63% of the strains belonged to group B1. The analyzed waters were potential reservoirs for DEC and could act as a source for infection of humans. Preventive measures are needed to avoid such contamination.

Isolation and characterization of catabolite repression-resistant mutants of Escherichia coli

1977 ◽  
Vol 23 (10) ◽  
pp. 1384-1393 ◽  
Author(s):  
Glen D. Armstrong ◽  
Hiroshi Yamazaki
Keyword(s):  
Escherichia Coli ◽  
Catabolite Repression ◽  
Coli Strain ◽  
Wild Type ◽  
Phosphotransferase System ◽  
E Coli ◽  
Isolation And Characterization ◽  
In The Wild ◽  
Resistant Mutants

A method has been developed for the isolation of Escherichia coli mutants which are resistant to catabolite repression. The method is based on the fact that a mixture of glucose and gluconate inhibits the development of chemotactic motility in the wild type, but not in the mutants. A motile E. coli strain was mutagenized and grown in glucose and gluconate. Mutants which were able to swim into a tube containing a chemotactic attractant (aspartic acid) were isolated. Most of these mutants were able to produce β-galactosidase in the presence of glucose and gluconate and were normal in their ability to degrade adenosine 3′,5′-cyclic monophosphate. Some of these mutants were defective in the glucose phosphotransferase system.

scholarly journals Genomic Insights into a Colistin-Resistant Uropathogenic Escherichia coli Strain of O23:H4-ST641 Lineage Harboring mcr-1.1 on a Conjugative IncHI2 Plasmid from Egypt

2021 ◽  
Vol 9 (4) ◽  
pp. 799
Author(s):  
Azza S. Zakaria ◽  
Eva A. Edward ◽  
Nelly M. Mohamed
Keyword(s):  
Escherichia Coli ◽  
Multidrug Resistant ◽  
Coli Strain ◽  
Colistin Resistance ◽  
E Coli ◽  
Agriculture Sector ◽  
Potential Reservoir ◽  
Clinical Source ◽  
Tract Infections

The reintroduction of colistin, a last-resort antibiotic for multidrug-resistant pathogens, resulted in the global spread of plasmid-mediated mobile colistin resistance (mcr) genes. Our study investigated the occurrence of colistin resistance among Escherichia coli isolated from patients with urinary tract infections admitted to a teaching hospital in Egypt. Out of 67 isolates, three isolates were colistin-resistant, having a minimum inhibitory concentration of 4 µg/mL and possessing the mcr-1 gene. A double mechanism of colistin resistance was detected; production of mcr-1 along with amino acid substitution in PmrB (E123D and Y358N) and PmrA (G144S). Broth mating experiments inferred that mcr-1 was positioned on conjugative plasmids. Whole-genome sequencing of EC13049 indicated that the isolate belonged to O23:H4-ST641 lineage and to phylogroup D. The mcr-1-bearing plasmid corresponded to IncHI2 type with a notable similarity to other E. coli plasmids previously recovered from Egypt. The unbanned use of colistin in the Egyptian agriculture sector might have created a potential reservoir for the mcr-1 gene in food-producing animals that spread to humans. More proactive regulations must be implemented to prevent further dissemination of this resistance. This is the first characterization of mcr-1-carrying IncHI2:ST4 plasmid recovered from E. coli of a clinical source in Egypt.

Prevalence and Characterization of Typical and Atypical Escherichia coli from Fish Sold at Retail in Cochin, India

2005 ◽  
Vol 68 (10) ◽  
pp. 2208-2211 ◽  
Author(s):  
NIRMALA THAMPURAN ◽  
A. SURENDRARAJ ◽  
P. K. SURENDRAN
Keyword(s):  
Escherichia Coli ◽  
Toxin Production ◽  
Latex Agglutination ◽  
Retail Markets ◽  
Fresh Fish ◽  
E Coli ◽  
Agglutination Method ◽  
Frozen Fish ◽  
The Tropics

Escherichia coli is a common contaminant of seafood in the tropics and is often encountered in high numbers. The count of E. coli as well as verotoxigenic E. coli O157:H7 was estimated in 414 finfish samples composed of 23 species of fresh fish from retail markets and frozen fish from cold storage outlets in and around Cochin, India. A total of 484 presumptive E. coli were isolated, and their indole–methyl red–Voges-Proskauer–citrate (IMViC) pattern was determined. These strains were also tested for labile toxin production by a reverse passive latex agglutination method and checked for E. coli serotype O157 by latex agglutination with O157-specific antisera. Certain biochemical marker tests, such as methylumbelliferyl-β-glucuronide (MUG), sorbitol fermentation, decarboxylase reactions, and hemolysis, which are useful for screening pathogenic E. coli, were also carried out. Results showed that 81.4% of the E. coli isolates were sorbitol positive. Among this group, 82% were MUG positive, and 14.46% of the total E. coli isolates showed human blood hemolysis. None of the isolates were positive for agglutination with E. coli O157 antisera nor did any produce heat-labile enterotoxin. This study indicates that typical E. coli O157 or labile toxin–producing E. coli is absent in the fish and fishery environments of Cochin (India). However, the presence of MUG and sorbitol-negative strains that are also hemolytic indicates the existence of aberrant strains, which require further investigation.

scholarly journals Characterization of a Hemoglobin Protease Secreted by the Pathogenic Escherichia coli Strain EB1

1998 ◽  
Vol 188 (6) ◽  
pp. 1091-1103 ◽  
Author(s):  
Ben R. Otto ◽  
Silvy J.M. van Dooren ◽  
Jan H. Nuijens ◽  
Joen Luirink ◽  
Bauke Oudega
Keyword(s):  
Escherichia Coli ◽  
Pathogenic Bacteria ◽  
Affinity Purification ◽  
Coli Strain ◽  
E Coli ◽  
Heme Acquisition ◽  
Pathogenic Escherichia Coli ◽  
Iga1 Protease ◽  
Animal Pathogens

Many pathogenic bacteria can use heme compounds as a source of iron. Pathogenic Escherichia coli strains are capable of using hemoglobin as an iron source. However, the mechanism of heme acquisition from hemoglobin is not understood for this microorganism. We present the first molecular characterization of a hemoglobin protease (Hbp) from a human pathogenic E. coli strain. The enzyme also appeared to be a heme-binding protein. Affinity purification of this bifunctional protein enabled us to identify the extracellular gene product, and to clone and analyze its gene. A purification procedure developed for Hbp allowed us to perform functional studies. The protein interacted with hemoglobin, degraded it and subsequently bound the released heme. These results suggest that the protein is involved in heme acquisition by this human pathogen. Hbp belongs to the so-called IgA1 protease-like proteins, as indicated by the kinetics of its membrane transfer and DNA sequence similarity. The gene of this protein appears to be located on the large pColV-K30 episome, that only has been isolated from human and animal pathogens. All these characteristics indicate that Hbp may be an important virulence factor that may play a significant role in the pathogenesis of E. coli infections.

scholarly journals Coculture of Escherichia coli O157:H7 with a Nonpathogenic E. coli Strain Increases Toxin Production and Virulence in a Germfree Mouse Model

2015 ◽  
Vol 83 (11) ◽  
pp. 4185-4193 ◽  
Author(s):  
Kakolie Goswami ◽  
Chun Chen ◽  
Lingzi Xiaoli ◽  
Kathryn A. Eaton ◽  
Edward G. Dudley
Keyword(s):  
Escherichia Coli ◽  
Foodborne Pathogen ◽  
Toxin Production ◽  
Coli Strain ◽  
Content Type ◽  
Infectious Dose ◽  
Shiga Toxins ◽  
E Coli ◽  
Nonpathogenic Strain ◽  
Uremic Syndrome

ABSTRACTEscherichia coliO157:H7 is a notorious foodborne pathogen due to its low infectious dose and the disease symptoms it causes, which include bloody diarrhea and severe abdominal cramps. In some cases, the disease progresses to hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS), due to the expression of one or more Shiga toxins (Stx). Isoforms of Stx, including Stx2a, are encoded within temperate prophages. In the presence of certain antibiotics, phage induction occurs, which also increases the expression of toxin genes. Additionally, increased Stx2 accumulation has been reported when O157:H7 was cocultured with phage-susceptible nonpathogenicE. coli. This study characterized anE. coliO157:H7 strain, designated PA2, that belongs to the hypervirulent clade 8 cluster. Stx2a levels after ciprofloxacin induction were lower for PA2 than for the prototypical outbreak strains Sakai and EDL933. However, during coculture with the nonpathogenic strainE. coliC600, PA2 produced Stx2a levels that were 2- to 12-fold higher than those observed during coculture with EDL933 and Sakai, respectively. Germfree mice cocolonized by PA2 and C600 showed greater kidney damage, increased Stx2a accumulation in feces, and more visible signs of disease than mice given PA2 or C600 alone. These data suggest one mechanism by which microorganisms associated with the colonic microbiota could enhance the virulence ofE. coliO157:H7, particularly a subset of clade 8 strains.

Primary structure determination of Escherichia coli heat-stable enterotoxin of porcine origin

1983 ◽  
Vol 61 (5) ◽  
pp. 287-292 ◽  
Author(s):  
Claude Lazure ◽  
Nabil G. Seidah ◽  
Michel Chrétien ◽  
Réal Lallier ◽  
Serge St-Pierre
Keyword(s):  
Escherichia Coli ◽  
Chemical Characterization ◽  
Coli Strain ◽  
Disulfide Bridges ◽  
E Coli ◽  
Heat Stable ◽  
Porcine Origin ◽  
Quantitative Amino Acid Analysis

The chemical characterization of Escherichia coli heat-stable enterotoxin (ST) is described. The toxin was isolated and purified to homogeneity from the E. coli strain F11 (PI55) of porcine origin. Following quantitative amino acid analysis, the enterotoxin was found to contain 18 amino acids including 6 cysteines, but was devoid of Ser, Val, Met, Ile, Lys, His, and Arg residues. All cysteine residues were found to be involved in disulfide bridges, even though their positions could not be localized. The enterotoxin thus has a molecular weight of 1979 and was shown to be an octadecapeptide with the following sequence: H2N-Asn-Thr-Phe-Tyr-Cys-Cys-Glu-Leu-Cys-Cys-Asn-Pro-Ala-Cys-Ala-Gly-Cys-Tyr-COOH. Its relationship to other known enterotoxins is discussed.

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