Subtyping of<i>Escherichia coli</i>O157:H7 Strains Isolated from Human Infections and Healthy Cattle in Argentina

D'Astek, Beatriz A.; Castillo, L. L. Del; Miliwebsky, Elizabeth; Carbonari, Carolina; Deza, Natalia; Chinen, Isao; Manfredi, Eduardo; Leotta, Gerardo Aníbal; Masana, Marcelo; Rivas, Marta

doi:10.1089/fpd.2011.1062

Cited by 12 publications

(8 citation statements)

References 43 publications

(38 reference statements)

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“…In the USA, 15 different PFGE profiles were determined in 254 E. coli O157:H7 isolates from cattle (Jacob et al 2011). In Argentina, 280 E. coli O157:H7 strains isolated from humans and cattle showed 148 PFGE patterns, and the strains were found to be 75% similar (D'Astek et al 2012). In England and Wales, 57 PFGE patterns were found among 228 E. coli O157:H7 isolates from cattle (Liebana et al 2003).…”

Section: Discussionmentioning

confidence: 98%

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Molecular characterisation of Shiga toxin-producing Escherichia coli O157:H7 isolates from cattle in eastern Turkey

Kalender¹,

Kılıç²

2016

Vet. Med. - Czech

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Shiga toxin-producing Escherichia coli (STEC) O157:H7 is an important foodborne pathogen worldwide. In Turkey, little is known about the molecular characteristics of STEC O157:H7 isolates. The aim of this study was to examine the genetic diversity of STEC O157:H7 isolates from cattle in Turkey using pulsed-field gel electrophoresis (PFGE). A total of 18 STEC O157:H7 strains were isolated from 540 rectal swab samples of slaughtered cattle in two abattoirs (coded A and B) located in eastern Turkey. The presence of virulence genes (stx1, stx2, hlyA and eae) was detected using the polymerase chain reaction. Of the 18 STEC O157:H7 isolates, 14 had stx2, hlyA, and eae genes. Four of the isolates were positive for stx1, stx2, hlyA, and eae genes. Thirteen different PFGE patterns were observed among the STEC O157:H7 isolates. The most common PFGE pattern was X1, which was detected in six STEC O157:H7 isolates. These six isolates contained the same virulence genes (stx2, eae and hlyA). However, some of the isolates containing the same virulence genes showed different PFGE profiles. Eleven different PFGE patterns were detected among the isolates from abattoir B, and two different PFGE patterns were detected among the isolates from abattoir A. The results of PFGE revealed a wide genetic diversity among the STEC O157:H7 isolates from cattle in Turkey. This is the first study on PFGE typing of STEC O157:H7 isolates from cattle in Turkey and further studies are needed.

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Section: Discussionmentioning

confidence: 98%

“…Humans can be infected by consumption of food and water contaminated with animal faeces (Ferreira et al 2014). STEC O157:H7 causes diarrhoea, haemorrhagic colitis, haemolytic-uremic syndrome (HUS) and thrombotic thrombocytopenic purpura in humans (D'Astek et al 2012;Chui et al 2015). It may lead to death in some people (Money et al 2010).…”

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confidence: 99%

Molecular characterisation of Shiga toxin-producing Escherichia coli O157:H7 isolates from cattle in eastern Turkey

Kalender¹,

Kılıç²

2016

Vet. Med. - Czech

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“…Stx1a, Stx2a, Stx2c, and Stx2d were found to be significantly associated with STEC from bovines and food of bovine origin (18,144,251,252). Stx2a is highly associated with STEC strains causing HUS in humans, such as O157:H7 and O104:H4 (43,234,253). Stx2a, Stx2c, and Stx2d genes show little differences in their genotypes (46), and PCR-RFLP typing was found useful for detecting multiple types of these genes, which are frequently present in single STEC strains (46,86).…”

Section: Subtyping Of Stec-and Ehec-related Virulence Genesmentioning

confidence: 98%

Detection of Shiga Toxin-Producing Escherichia coli from Nonhuman Sources and Strain Typing

Beutin

Fach

2014

Microbiol Spectr

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Shiga toxin-producing Escherichia coli (STEC) strains are commonly found in the intestine of ruminant species of wild and domestic animals. Excretion of STEC with animal feces results in a broad contamination of food and the environment. Humans get infected with STEC through ingestion of contaminated food, by contact with the environment, and from STEC-excreting animals and humans. STEC strains can behave as human pathogens, and some of them, called enterohemorrhagic E. coli (EHEC), may cause hemorrhagic colitis (HC) and hemolytic-uremic syndrome (HUS). Because of the diversity of STEC types, detection strategies for STEC and EHEC are based on the identification of Shiga toxins or the underlying genes. Cultural enrichment of STEC from test samples is needed for identification, and different protocols were developed for this purpose. Multiplex real-time PCR protocols (ISO/CEN TS13136 and USDA/FSIS MLG5B.01) have been developed to specifically identify EHEC by targeting the LEE (locus of enterocyte effacement)-encoded eae gene and genes for EHEC-associated O groups. The employment of more genetic markers (nle and CRISPR) is a future challenge for better identification of EHEC from any kinds of samples. The isolation of STEC or EHEC from a sample is required for confirmation, and different cultivation protocols and media for this purpose have been developed. Most STEC strains present in food, animals, and the environment are eae negative, but some of these strains can cause HC and HUS in humans as well. Phenotypic assays and molecular tools for typing EHEC and STEC strains are used to detect and characterize human pathogenic strains among members of the STEC group.

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“…For example, ST73 includes model pathogenic strains, such as urosepsis isolate CFT073, but it also includes probiotic strain Nissle1917 and asymptomatic bacteriuria strain 83972 (12,13). Such strains with different pathogenicities within the same ST can be shown to belong to distinct genetic lineages by either PFGE or mosaic gene mapping and, recently, partial-or whole-genome sequencing (14)(15)(16)(17). These studies suggest that to understand the physiological significance of the clonal diversity of pathogenic bacterial species, it is necessary to examine the molecular basis of genetic variability among strains with identical MLST profiles.…”

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Role of Homologous Recombination in Adaptive Diversification of Extraintestinal Escherichia coli

et al. 2013

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The contribution of homologous exchange (recombination) of core genes in the adaptive evolution of bacterial pathogens is not well understood. To investigate this, we analyzed fully assembled genomes of two Escherichia coli strains from sequence type 131 (ST131), a clonal group that is both the leading cause of extraintestinal E. coli infections and the main source of fluoroquinolone-resistant E. coli. Although the sequences of each of the seven multilocus sequence typing genes were identical in the two ST131 isolates, the strains diverged from one another by homologous recombination that affected at least 9% of core genes. This was on a par with the contribution to genomic diversity of horizontal gene transfer and point gene mutation. The genomic positions of recombinant and mobile genetic regions were partially linked, suggesting their concurrent occurrence. One of the genes affected by homologous recombination was fimH, which encodes mannose-specific type 1 fimbrial adhesin, resulting in functionally distinct copies of the gene in ST131 strains. One strain, a uropathogenic isolate, had a pathoadaptive variant of fimH that was acquired by homologous replacement into the commensal strain background. Close examination of FimH structure and function in additional ST131 isolates revealed that recombination led to acquisition of several functionally distinct variants that, upon homologous exchange, were targeted by a variety of pathoadaptive mutations under strong positive selection. Different recombinant fimH strains also showed a strong clonal association with ST131 isolates that had distinct fluoroquinolone resistance profiles. Thus, homologous recombination of core genes plays a significant role in adaptive diversification of bacterial pathogens, especially at the level of clonally related groups of isolates.

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Subtyping ofEscherichia coliO157:H7 Strains Isolated from Human Infections and Healthy Cattle in Argentina

Cited by 12 publications

References 43 publications

Molecular characterisation of Shiga toxin-producing Escherichia coli O157:H7 isolates from cattle in eastern Turkey

Molecular characterisation of Shiga toxin-producing Escherichia coli O157:H7 isolates from cattle in eastern Turkey

Detection of Shiga Toxin-Producing Escherichia coli from Nonhuman Sources and Strain Typing

Role of Homologous Recombination in Adaptive Diversification of Extraintestinal Escherichia coli

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