Virulence gene(s) Gamut of Enteropathogenic Escherichia coli (EPEC) and Shiga Toxin-Producing Escherichia coli (STEC) in Piglets with or without Diarrhoea in Mizoram (India)

Shiga toxin-producing Escherichia coli (STEC) strains also called verotoxin-producing E. coli (VTEC) represent one of the most important groups of food-borne pathogens that can cause several human diseases such as hemorrhagic colitis (HC) and hemolytic – uremic syndrome (HUS) worldwide. The ability of STEC strains to cause disease is associated with the presence of wide range of identified and putative virulence factors including those encoding Shiga toxin. In this study, we examined the distribution of various virulence determinants among STEC strains isolated in Poland from different sources. A total of 71 Shiga toxin-producing E. coli strains isolated from human, cattle and food over the years 1996 – 2010 were characterized by microarray and PCR detection of virulence genes. As stx1a subtype was present in all of the tested Shiga toxin 1 producing E. coli strains, a greater diversity of subtypes was found in the gene stx2, which occurred in five subtypes: stx2a, stx2b, stx2c, stx2d, stx2g. Among STEC O157 strains we observed conserved core set of 14 virulence factors, stable in bacteria genome at long intervals of time. There was one cattle STEC isolate which possessed verotoxin gene as well as sta1 gene encoded heat-stable enterotoxin STIa characteristic for enterotoxigenic E. coli. To the best of our knowledge, this is the first comprehensive analysis of virulence gene profiles identified in STEC strains isolated from human, cattle and food in Poland. The results obtained using microarrays technology confirmed high effectiveness of this method in determining STEC virulotypes which provides data suitable for molecular risk assessment of the potential virulence of this bacteria.

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Virulence gene profiles of Shiga-toxin producing Escherichia coli isolates from retail raw meat in Iran.

BULGARIAN JOURNAL OF VETERINARY MEDICINE ◽

10.15547/bjvm.953 ◽

2017 ◽

Vol 20 (1) ◽

pp. 19-26

Author(s):

M. Panahee ◽

H. Pourtaghi

Keyword(s):

Escherichia Coli ◽

Shiga Toxin ◽

Virulence Gene ◽

Raw Meat ◽

Gene Profiles

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Whole Genome Sequencing Characterization of Shiga Toxin–Producing Escherichia coli Isolated from Flour from Swiss Retail Markets

Journal of Food Protection ◽

10.4315/0362-028x.jfp-18-593 ◽

2019 ◽

Vol 82 (8) ◽

pp. 1398-1404 ◽

Cited By ~ 2

Author(s):

RENATE BOSS ◽

JOERG HUMMERJOHANN

Keyword(s):

Escherichia Coli ◽

Whole Genome Sequencing ◽

Genome Sequencing ◽

Shiga Toxin ◽

Severe Disease ◽

Virulence Gene ◽

Whole Genome ◽

N 93 ◽

Human Infections

ABSTRACT Shiga toxin–producing Escherichia coli (STEC) strains are often found in food and cause human infections. Although STEC O157:H7 is most often responsible for human disease, various non-O157 subtypes have caused individual human infections or outbreaks. The importance of STEC serogroup typing is decreasing while detection of virulence gene patterns has become more relevant. Whole genome sequencing (WGS) reveals the entire spectrum of pathogen information, such as toxin variant, serotype, sequence type, and virulence factors. Flour has not been considered as a vector for STEC; however, this product has been associated with several STEC outbreaks in the last decade. Flour is a natural product, and milling does not include a germ-reducing step. Flour is rarely eaten raw, but the risks associated with the consumption of unbaked dough are probably underestimated. The aim of this study was to determine the prevalence of STEC in flour samples (n = 93) collected from Swiss markets and to fully characterize the isolates by PCR assay and WGS. The prevalence of STEC in these flour samples was 10.8% as indicated by PCR, and a total of 10 STEC strains were isolated (two flour samples were positive for two STEC subtypes). We found one stx2-positve STEC isolate belonging to the classic serogroups frequently associated with outbreaks that could potentially cause severe disease. However, we also found several other common or less common STEC subtypes with diverse virulence patterns. Our results reveal the benefits of WGS as a characterization tool and that flour is a potentially and probably underestimated source for STEC infections in humans.

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