A portable and high-sensitivity optical sensing system for detecting fluorescently labeled enterohaemorrhagic Escherichia coli Shiga toxin 2B-subunit

Enterohaemorrhagic Escherichia coli (EHEC) produces Shiga toxin 1 (Stx1) and Shiga toxin 2 (Stx2). Although stx1 and stx2 were found within the late operons of the Stx-encoding phages (Stx-phages), stx1 could mainly be transcribed from the stx1 promoter (P Stx1), which represents the functional operator-binding site (Fur box) for the transcriptional regulator Fur (ferric uptake regulator), upstream of stx1. In this study, we found that the production of Stx1 by EHEC was affected by oxygen concentration. Increased Stx1 production in the presence of oxygen is dependent on Fur, which is an Fe2+-responsive transcription factor. The intracellular Fe2+ pool was lower under microaerobic conditions than under anaerobic conditions, suggesting that lower Fe2+ availability drove the formation of less Fe2+-Fur, less DNA binding to the P Stx1 region, and an increase in Stx1 production.

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A visual electrochemiluminescence resonance energy transfer/surface plasmon coupled electrochemiluminescence nanosensor for Shiga toxin-producing Escherichia coli detection

Green Chemistry ◽

10.1039/c8gc03010c ◽

2018 ◽

Vol 20 (24) ◽

pp. 5520-5527 ◽

Cited By ~ 21

Author(s):

Yang Liu ◽

Xueqian Chen ◽

Mengke Wang ◽

Qiang Ma

Keyword(s):

Escherichia Coli ◽

Energy Transfer ◽

Surface Plasmon ◽

Human Blood ◽

Shiga Toxin ◽

Rapid Detection ◽

Resonance Energy Transfer ◽

Resonance Energy ◽

High Sensitivity ◽

Excellent Selectivity

A BN QDs-based ECL biosensor was established for the rapid detection of STEC in human blood, showing excellent selectivity, stability and high sensitivity.

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Escherichia coli O80 hybrid pathotype strains producing Shiga toxin and ESBL: molecular characterization and potential therapeutic options

Journal of Antimicrobial Chemotherapy ◽

10.1093/jac/dkz484 ◽

2019 ◽

Vol 75 (3) ◽

pp. 537-542 ◽

Cited By ~ 2

Author(s):

Aurélie Cointe ◽

André Birgy ◽

Antoine Bridier-Nahmias ◽

Patricia Mariani-Kurkdjian ◽

Violaine Walewski ◽

...

Keyword(s):

Escherichia Coli ◽

Shiga Toxin ◽

Asymptomatic Carrier ◽

Resistance Mechanism ◽

Major Effect ◽

Health Concern ◽

Virulence Plasmid ◽

Enterohaemorrhagic Escherichia Coli ◽

Long Read ◽

Invasive Infections

Abstract Objectives Enterohaemorrhagic Escherichia coli (EHEC) infections may be complicated by haemolytic uraemic syndrome (HUS). The emerging worldwide EHEC serogroup O80 has acquired a mosaic plasmid combining extraintestinal virulence and antibiotic resistance. This hybrid pathotype is associated with invasive infections that require antibiotic therapy, classically not recommended in EHEC infections, increasing the risk of HUS. We characterized two ESBL-producing O80 EHEC strains, which is an unusual resistance mechanism among EHECs, and determined the safest therapy to be used for invasive infections. Methods WGS of two strains isolated from the stools of an asymptomatic carrier and a patient with HUS was performed using Illumina and Nanopore technologies. Generated reads were combined to assemble genomes. We determined the safest therapy by comparing Shiga toxin (Stx) production by the two strains in the presence of several antibiotics. Results The strains were genetically close to the O80 EHEC clone, belonging to ST301 and harbouring stx2d, eae-ξ, ehxA and genes characteristic of the extraintestinal virulence plasmid pS88. Long-read sequencing identified the acquisition of an additional plasmid harbouring CTX-M-type genes (blaCTX-M-14 and blaCTX-M-1). Azithromycin decreased Stx production at subinhibitory concentrations, ciprofloxacin increased it and imipenem had no major effect. The combination of azithromycin and imipenem overall reduced Stx production. Conclusions Acquisition of an additional plasmid harbouring ESBL genes is a step towards increasing the risk of O80 EHEC dissemination and represents a serious public health concern. The combination of azithromycin and imipenem reduced Stx production and suggests that this combination could be tested in clinical trials.

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MOLECULAR DETECTION OF ENTEROHAEMORRHAGIC ESCHERICHIA COLI IN RAW BEEF MEAT FROM ABEOKUTA, OGUN STATE, NIGERIA

African Journal of Science and Nature ◽

10.46881/ajsn.v10i0.189 ◽

2020 ◽

Vol 10 ◽

pp. 164

Author(s):

Anotu Mopelola Deji-Agboola ◽

Olubunmi Adetokunbo Osinupebi ◽

Rotimi Tope Akinlalu

Keyword(s):

Escherichia Coli ◽

Shiga Toxin ◽

Serological Test ◽

Polymerase Chain Reaction Method ◽

Open Market ◽

Macconkey Agar ◽

Public Health Importance ◽

E Coli ◽

Enterohaemorrhagic Escherichia Coli ◽

Meat Samples

The presence of Enterohaemorrhagic Escherichia coli in beef and beef products is of public health importance. Therefore, the current study was carried out to evaluate the prevalence of E. coli serotype O157:H7 from raw beef collected from Abeokuta. Meat samples from selected abattoir and open beef omarket in Abeokuta were aseptically collected into sterile peptone water, incubate at 37C for 24 hours and subcultured on MacConkey agar. The bacteria isolated were identified using standard method and owere cultured on Sorbitol MacConkey agar, incubated at 37C for 24hrs. Serological test was performed using O157:H7 polyvalent and monovalent anti-E. coli O and H sera. The presence of Shiga toxin 1 and 2 was detected by Polymerase Chain Reaction method. Antibiotic susceptibility testing was carried out using disk diffusion technique. Out of the 100 samples collected 60% yielded lactose fermenting colonies identified biochemically as E. coli, 43.3% from the abattoirs and 56.7% were from the open market. Only 3.3% of the Escherichia coli were non-Sorbitol fermenter and were confirmed as Enterohaemorrhagic Escherichia coli O157:H7 serologically, 1.7% carries the Stx 1 gene. The E. coli were resistant to Augmentin 95% and Cefuroxime 83.3%, Gentamycin 20%, Ofloxacin 21.7%, Ciprofloxacin 26.7%, Cefixime 38.3% and Ceftazidime 43.3%. The isolates that possessed Stx 1 gene were resistant to all the antibiotics tested. The meat samples in the abattoir and open market were contaminated with E coli which contain enterohaemorrhagic strains producing shiga toxin 1 (Stx 1) and were highly resistant to antibiotics.

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PREVALENCE OF ENTEROHAEMORRHAGIC ESCHERICHIA COLI O157:H7, SHIGA TOXIN GENES AND ANTIBIOTIC RESISTANCE IN CHILDREN AGED 0-5 YEARS WITH DIARRHOEA IN IBADAN, OYO STATE

African Journal of Science and Nature ◽

10.46881/ajsn.v10i0.190 ◽

2020 ◽

Vol 10 ◽

pp. 171

Author(s):

Anotu Mopelola Deji-Agboola ◽

Florence Adenike Bamigbola ◽

Olubunmi Adetokunbo Osinupebi

Keyword(s):

Escherichia Coli ◽

Antibiotic Resistance ◽

Shiga Toxin ◽

E Coli ◽

Enterohaemorrhagic Escherichia Coli ◽

Hand Wash ◽

Stool Samples ◽

Antibiotics Susceptibility ◽

Shiga Toxin Genes ◽

Cultured Bacteria

Diarrhoea is a predominant cause of childhood illness and death, Enterohaemorrhagic Escherichia coli (EHEC) have increasingly been recognised as an important cause of diarrhea all over the world. This study investigates the prevalence, presence of shiga toxin (Stx) and antibiotic resistance of Enterohaemorrhagic Escherichia coli (EHEC) O157:H7 in children with diarrhoea. Stool samples collected from children less than five year with diarrhoea were cultured, bacteria isolated were identified and antibiotics susceptibility testing was performed using standard methods. Entrohaemorrhagic E. coli O157:H7 and Stx were screened using serology and Polymerase Chain Reaction respectively. Structured questionnaires were administered to determine factors that predispose the children to diarrhoea. A total of 301/370 (81.4%) stool samples yielded bacterial growth, 261/301 (86.7%) were gram negative bacilli, 188/261 (72.0%) Escherichia coli, 163/188 (86.7%) were EHEC O157: H7. Out of the 5 EHEC O157:H7 only 2 possessed Stx genes, 1 have Stx 2 while the other have both Stx 1 and Stx 2 gene. Escherichia coli were resistant to Tetracycline 98.4%, Ampicillin 83.0%, Cefuroxime 76.5%, Augmentin 62.9% and Gentamycin 51.4%, all the EHEC O157:H7 were resistant to Tetracycline and Ampicillin. Diarrhoea in the children were significantly associated with hand wash after toilet, eating pastries, sources of drinking water and the educational level of parent/caretaker (p-values = 0.04, 0.00, 0.00 and 0.03 respectively). The presence of EHEC O157:H7 carrying Stx 1 and Stx 2 gene as well as resistant to all antibiotics tested is a pointer for more stringent and better screening for diarrhoea infections in children.

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The effect of two ribonucleases on the production of Shiga toxin and stx-bearing bacteriophages in Enterohaemorrhagic Escherichia coli

Scientific Reports ◽

10.1038/s41598-021-97736-z ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Patricia B. Lodato

Keyword(s):

Escherichia Coli ◽

Shiga Toxin ◽

Toxin Production ◽

Lytic Cycle ◽

Enterohaemorrhagic Escherichia Coli ◽

Q Protein ◽

Shiga Toxin 2 ◽

Intestinal Pathogens ◽

Transcription Antitermination ◽

Conventional Antibiotics

AbstractEnterohaemorrhagic Escherichia coli (EHEC) comprise a group of intestinal pathogens responsible for a range of illnesses, including kidney failure and neurological compromise. EHEC produce critical virulence factors, Shiga toxin (Stx) 1 or 2, and the synthesis of Stx2 is associated with worse disease manifestations. Infected patients only receive supportive treatment because some conventional antibiotics enable toxin production. Shiga toxin 2 genes (stx2) are carried in λ-like bacteriophages (stx2-phages) inserted into the EHEC genome as prophages. Factors that cause DNA damage induce the lytic cycle of stx2-phages, leading to Stx2 production. The phage Q protein is critical for transcription antitermination of stx2 and phage lytic genes. This study reports that deficiency of two endoribonucleases (RNases), E and G, significantly delayed cell lysis and impaired production of both Stx2 and stx2-phages, unlike deficiency of either enzyme alone. Moreover, scarcity of both enzymes reduced the concentrations of Q and stx2 transcripts and slowed cell growth.

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