Characterization of Shiga toxin producing E. coli and O157 serotype E. coli isolated in France from healthy domestic cattle

2001 ◽  
Vol 63 (3) ◽  
pp. 217-223 ◽  
Author(s):  
François Rogerie ◽  
Armelle Marecat ◽  
Stéphanie Gambade ◽  
Francis Dupond ◽  
Pierre Beaubois ◽  
...  
Keyword(s):  
Shiga Toxin ◽  
E Coli

scholarly journals Characterization of Shiga Toxin-ProducingEscherichia coliIsolated from Ground Beef Collected in Different Socioeconomic Strata Markets in Buenos Aires, Argentina

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Patricia Llorente ◽  
Laura Barnech ◽  
Kinue Irino ◽  
María Valeria Rumi ◽  
Adriana Bentancor
Keyword(s):  
Shiga Toxin ◽  
Buenos Aires ◽  
Ground Beef ◽  
Contamination Level ◽  
Contamination Rate ◽  
E Coli ◽  
Virulence Markers ◽  
Route Of Transmission ◽  
Socioeconomic Strata

Consumption of raw/undercooked ground beef is the most common route of transmission of Shiga toxin-producingE. coli(STEC). The aim of the study was to determine the STEC contamination level of the ground beef samples collected in 36 markets of different socioeconomic strata in Buenos Aires, Argentina, and the characterization of the isolated strains. Ninety-one out of 252 (36.1%) samples werestx+. Fifty-seven STEC strains were recovered. Eleven STEC strains belonged to O157 serogroup, and 46 to non-O157 serogroups. Virulence markers of the 57 STEC werestx1, 5.3% (3/57);stx2, 86.0% (49/57);stx1/stx2, 8.8% (5/57);ehxA, 61.4% (35/57);eae, 26.3% (15/57);saa, 24.6% (14/57). Shiga toxin subtypes werestx2, 31.5% (17/54);stx2c-vhb, 24.1% (13/54);stx2c-vha, 20.4% (11/54);stx2/stx2c-vha, 14.8% (8/54);stx2/stx2c-vhb, 5.6% (3/54);stx2c-vha/vhb, 3.7% (2/54). Serotypes O178:H19 and O157:H7 were prevalent. Contamination rate of STEC in all strata was high, and the highest O157 contamination was observed at low strata at several sampling rounds. Persistence of STEC was not detected. Sixteen strains (28.1%) were resistant to ampicillin, streptomycin, amikacin, or tetracycline. The STEC contamination level of ground beef could vary according to the sociocultural characteristics of the population.

scholarly journals Characterization of a Shiga Toxin-Encoding Temperate Bacteriophage of Shigella sonnei

2001 ◽  
Vol 69 (12) ◽  
pp. 7588-7595 ◽  
Author(s):  
Eckhard Strauch ◽  
Rudi Lurz ◽  
Lothar Beutin
Keyword(s):  
Shiga Toxin ◽  
Regulatory Region ◽  
Shigella Sonnei ◽  
Shigella Dysenteriae ◽  
Nucleotide Sequencing ◽  
Temperate Bacteriophage ◽  
Cross Hybridization ◽  
E Coli ◽  
K 12

ABSTRACT A Shiga toxin (Stx)-encoding temperate bacteriophage ofShigella sonnei strain CB7888 was investigated for its morphology, DNA similarity, host range, and lysogenization inShigella and Escherichia coli strains. Phage 7888 formed plaques on a broad spectrum of Shigella strains belonging to different species and serotypes, including Stx-producingShigella dysenteriae type 1. With E. coli, only strains with rough lipopolysaccharide were sensitive to this phage. The phage integrated into the genome of nontoxigenic S. sonneiand laboratory E. coli K-12 strains, which became Stx positive upon lysogenization. Moreover, phage 7888 is capable of transducing chromosomal genes in E. coli K-12. The relationships of phage 7888 with the E. coli Stx1-producing phage H-19B and the E. coli Stx2-producing phage 933W were investigated by DNA cross-hybridization of phage genomes and by nucleotide sequencing of an 8,053-bp DNA region of the phage 7888 genome flanking the stx genes. By these methods, a high similarity was found between phages 7888 and 933W. Much less similarity was found between phages H-19B and 7888. As in the other Stx phages, a regulatory region involved in Q-dependent expression is found upstream of stxA and stxB (stx gene) in phage 7888. The morphology of phage 7888 was similar to that of phage 933W, which shows a hexagonal head and a short tail. Our findings demonstrate that stx genes are naturally transferable and are expressed in strains of S. sonnei, which points to the continuous evolution of human-pathogenic Shigella by horizontal gene transfer.

scholarly journals Prevalence and molecular characterization of Shiga toxin-producing escherichia coli isolates from human and sheep in Al-Madinah Al-Munawarah

Infectio ◽  
2017 ◽  
Vol 21 (2) ◽  
Author(s):  
Eman Fathi Sharafa ◽  
Iman I. Shabanaa
Keyword(s):  
Escherichia Coli ◽  
Foodborne Pathogens ◽  
Shiga Toxin ◽  
Genetic Relatedness ◽  
Control Measures ◽  
Health Concern ◽  
Global Public Health ◽  
E Coli ◽  
Life Threatening

Shiga toxin-producing Escherichia coli (STEC) strains have emerged as important foodborne pathogens of global public health concern, causing life-threatening diseases. Sheep and their products have been documented as important reservoirs for STECs, especially E. coli O157. The aim of this study was to investigate STECs from diarrheal human and sheep in Al-Madinah Al-Munawarah, Saudi Arabia. Fecal samples were collected between June and August, 2015 from diarrheal humans (n = 134) and sheep (n = 87). Presumptive E. coli human-and sheep-isolated strains were identified for their serotypes, the associated virulence genes (Shiga toxin [stx1 , stx2 ], haemolysin [ehxA] and intimin [eae]) by polymerase chain reaction and their susceptibility to antibiotics. Pulsed-field gel electrophoresis (PFGE) was used to demonstrate the genetic relatedness between Serotype O157:H7 human- and sheep-isolated strains. Forty eight (48/221; 21.7%) STECs were recovered from both human and sheep, their serotypes were as follows: O157:H7, O26:H11, O157:HNM, O26:HNM, O128:H2, O48:HNM, O111:HNM and OUT:HUT. Various virulence profiles and multiple antibiotic resistance were observed among the isolates. Twenty eight O157:H7 serotypes (17 human isolates and 11 sheep isolates) were identified in 13 PFGE pulsotypes, where human and sheep isolates were highly related. PFGE banding profiles together with serotypes and genotypes afford proof that human and sheep can be colonized and infected with similar E. coli O157:H7 strains. Our findings highlight the importance of epidemiological and microbiological surveillance of STECs; as well as the development of control measures to decrease risks associated with zoonotic O157:H7.

scholarly journals Precision long-read metagenomics sequencing for food safety by detection and assembly of Shiga toxin-producing Escherichia coli in irrigation water

2020 ◽  
Author(s):  
Meghan Maguire ◽  
Julie A. Kase ◽  
Dwayne Roberson ◽  
Tim Muruvanda ◽  
Eric W. Brown ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Food Safety ◽  
Shiga Toxin ◽  
Irrigation Water ◽  
Foodborne Illness ◽  
Nanopore Sequencing ◽  
E Coli ◽  
Antimicrobial Resistance Genes ◽  
Metagenomic Sample

ABSTRACTShiga toxin-producing Escherichia coli (STEC) contamination of agricultural water might be an important factor to recent foodborne illness and outbreaks involving leafy greens. Whole genome sequencing generation of closed bacterial genomes plays an important role in source tracking. We aimed to determine the limits of detection and classification of STECs by qPCR and nanopore sequencing using enriched irrigation water artificially contaminated with E. coli O157:H7 (EDL933). We determined the limit of STEC detection by qPCR to be 30 CFU/reaction, which is equivalent to 105 CFU/ml in the enrichment. By using Oxford Nanopore’s EPI2ME WIMP workflow and de novo assembly with Flye followed by taxon classification with a k-mer analysis software (Kraken), E. coli O157:H7 could be detected at 103 CFU/ml (68 reads) and a complete fragmented E. coli O157:H7 metagenome-assembled genome (MAG) was obtained at 105-108 CFU/ml. Using a custom script to extract the E. coli reads, a completely closed MAG was obtained at 107-108 CFU/ml and a complete, fragmented MAG was obtained at 105-106 CFU/ml. In silico virulence detection for E. coli MAGs for 105-108 CFU/ml showed that the virulotype was indistinguishable from the spiked E. coli O157:H7 strain. We further identified the bacterial species in the un-spiked enrichment, including antimicrobial resistance genes, which could have important implications to food safety. We propose this workflow could be used for detection and complete genomic characterization of STEC from a complex microbial sample and could be applied to determine the limit of detection and assembly of other foodborne bacterial pathogens.IMPORTANCEFoodborne illness caused by Shiga toxin-producing E. coli (STEC) ranges in severity from diarrhea to hemolytic uremic syndrome and produce-related incidence is increasing. The pervasive nature of E. coli requires not only detection, but also a complete genome to determine potential pathogenicity based on stx and eae genes, serotype, and other virulence factors. We have developed a pipeline to determine the limits of nanopore sequencing for STECs in a metagenomic sample. By utilizing the current qPCR in the FDA Bacteriological Analytical Manual (BAM) Chapter 4A, we can quantify the amount of STEC in the enrichment and then sequence and classify the STEC in less than half the time as current protocols that require a single isolate. These methods have wide implications for food safety, including decreased time to STEC identification during outbreaks, characterization of the microbial community, and the potential to use these methods to determine the limits for other foodborne pathogens.

Prevalence and Characterization of Escherichia coli O157:H7 on Pork Carcasses and in Swine Colon Contents from Provincially Licensed Abattoirs in Alberta, Canada

2020 ◽  
Vol 83 (11) ◽  
pp. 1909-1917
Author(s):  
SAIDA ESSENDOUBI ◽  
XIANQIN YANG ◽  
ROBIN KING ◽  
JULIA KEENLISIDE ◽  
JAVIER BAHAMON ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Gel Electrophoresis ◽  
Mean Value ◽  
Pulsed Field Gel Electrophoresis ◽  
Escherichia Coli O157 ◽  
Pulsed Field ◽  
E Coli ◽  
Swine Farms

ABSTRACT The objective of this study was to determine the prevalence of Shiga toxin–producing Escherichia coli (STEC) O157:H7 in colon contents and on carcasses from pigs slaughtered at provincially licensed abattoirs (PLAs) in Alberta, Canada. In 2017, carcass sponge samples and colon content samples were collected from 504 healthy market hogs at 39 PLAs and analyzed for E. coli O157:H7. Carcass samples were also analyzed for E. coli and aerobic colony count (ACC). Nine (1.8%) of 504 carcass samples were confirmed positive for E. coli O157:H7. Seven (1.4%) of 504 colon content samples were confirmed positive for E. coli O157:H7. These positives were found in 5 (12.8%) of 39 PLAs from hogs originating from eight farms. The E. coli O157:H7 isolates recovered from the positive samples (n = 1 isolate per sample) were clonal, as determined by pulsed-field gel electrophoresis. Six E. coli O157:H7 isolates obtained over 8 months from one PLA that only processed hogs and sourced hogs from one farm had indistinguishable pulsed-field gel electrophoresis patterns. All 16 E. coli O157:H7 isolates harbored eae and ehxA and were of stx2a subtype, suggesting that swine can carry E. coli O157:H7 of importance to human health. All carcass sponge swabs (100%) were positive for ACC. E. coli was present in 72% of carcass swabs. Carcasses from PLAs slaughtering both beef and hogs had a numerically higher ACC mean value but not statistically different compared with the carcasses from PLAs slaughtering only swine (2,799 and 610 CFU/cm2, respectively). E. coli showed a similar trend with a mean value of 0.88 CFU/cm2 in PLAs slaughtering both species and 0.26 CFU/cm2 in PLAs slaughtering only swine (P ≤ 0.05). This study provides evidence that healthy market hogs from different producers and farms in Alberta can carry E. coli O157:H7, and some strains of the organism may be able to establish persistence on some swine farms. HIGHLIGHTS

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