Phage Types and Genotypes of Shiga Toxin-Producing
            <i>Escherichia coli</i>
            O157:H7 Isolates from Humans and Animals in Spain: Identification and Characterization of Two Predominating Phage Types (PT2 and PT8)

Mora, Azucena; Blanco, Miguel; Blanco, Jesús E.; Alonso, Marı́a Pilar; Dhabi, Ghizlane; Thomson-Carter, Fiona M.; Usera, M. A.; Bartolomé, Rosa; Prats, G; Blanco, Jorge

doi:10.1128/jcm.42.9.4007-4015.2004

Cited by 47 publications

(39 citation statements)

References 63 publications

(60 reference statements)

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“…None contained sfpA, which encodes fimbriae and is a defining characteristic of SF EHEC O157:NM (8). The 391 EHEC O157:H7 strains investigated belonged to 19 phage types (PTs) ( Table 1), which represent the spectrum of PTs within E. coli O157:H7 in Germany and are in concordance with other studies from Germany (1,13) and other European countries (14,20). The cdt-V-positive strains belonged to five different PTs (Table 1).…”

supporting

confidence: 73%

Cytolethal Distending Toxin in Escherichia coli O157:H7: Spectrum of Conservation, Structure, and Endothelial Toxicity

Friedrich

Bielaszewska

et al. 2006

J Clin Microbiol

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We identified the cytolethal distending toxin V (CDT-V) gene cluster in 19 (4.9%) of 391 enterohemorrhagic Escherichia coli O157:H7. cdt-V ؉ strains belonged to five phage types (PTs) and were most frequent within PTs 14 and 34. CDT-V was expressed in all but two cdt-V ؉ strains and was lethal to cultured endothelial cells. Subtyping schemes should include cdt-V as a marker to differentiate E. coli O157:H7 even within the same phage type.

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supporting

confidence: 73%

Cytolethal Distending Toxin in Escherichia coli O157:H7: Spectrum of Conservation, Structure, and Endothelial Toxicity

Friedrich

Bielaszewska

et al. 2006

J Clin Microbiol

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“…The existence of a VTEC O157 subpopulation has also been supported by the observation that VTEC O157 strains isolated from cases of human disease usually belong to a nonrandom subset of PTs (15)(16)(17)(18)(19)(20). Although the phage types are related to the susceptibility of VTEC O157 to infection with a panel of phages and may not correlate with their virulence potentials, significant differences have been reported in the distribution of the PTs among VTEC O157 isolates from human and bovine sources by different authors (15)(16)(17)(18)(19)(20) and can thus be considered a good epidemiological marker for the purpose of identifying VTEC O157 subpopulations.…”

Section: Discussionmentioning

confidence: 74%

“…Although this technique was developed more than 2 decades ago, it still remains a useful approach to characterize VTEC O157 strains. Interestingly, it has been observed that while the isolates from cattle may span a wide portion of the entire PT panel (15), the strains isolated from both outbreaks and sporadic cases of human disease usually belong to a restricted number of PTs. In particular, VTEC O157 strains isolated from human infections in Europe mainly belong to PT8 and PT2 (15)(16)(17)(18), PT21/28 (19,20), and PT32 (16).…”

Section: Erocytotoxin (Vt)-producing Escherichia Coli (Vtec) O157mentioning

confidence: 99%

“…Interestingly, it has been observed that while the isolates from cattle may span a wide portion of the entire PT panel (15), the strains isolated from both outbreaks and sporadic cases of human disease usually belong to a restricted number of PTs. In particular, VTEC O157 strains isolated from human infections in Europe mainly belong to PT8 and PT2 (15)(16)(17)(18), PT21/28 (19,20), and PT32 (16). The uneven PT distribution between the strains isolated from human disease and the strains isolated from the animal reservoir seems to indicate that a subpopulation of VTEC O157 might have evolved that is either more virulent for the human host or better adapted to survive in the food chain.…”

Section: Erocytotoxin (Vt)-producing Escherichia Coli (Vtec) O157mentioning

confidence: 99%

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Identification and Characterization of a Peculiar vtx2 -Converting Phage Frequently Present in Verocytotoxin-Producing Escherichia coli O157 Isolated from Human Infections

et al. 2014

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dCertain verocytotoxin-producing Escherichia coli (VTEC) O157 phage types (PTs), such as PT8 and PT2, are associated with severe human infections, while others, such as PT21, seem to be restricted to cattle. In an attempt to delve into the mechanisms underlying such a differential distribution of PTs, we performed microarray comparison of human PT8 and animal PT21 VTEC O157 isolates. The main differences observed were in the vtx2-converting phages, with the PT21 strains bearing a phage identical to that present in the reference strain EDL933, BP933W, and all the PT8 isolates displaying lack of hybridization in some regions of the phage genome. We focused on the region spanning the gam and cII genes and developed a PCR tool to investigate the presence of PT8-like phages in a panel of VTEC O157 strains belonging to different PTs and determined that a vtx2 phage reacting with the primers deployed, which we named ⌽8, was more frequent in VTEC O157 strains from human disease than in bovine strains. No differences were observed in the production of the VT2 mRNA when ⌽8-positive strains were compared with VTEC O157 possessing BP933W. Nevertheless, we show that the gam-cII region of phage ⌽8 might carry genetic determinants downregulating the transcription of the genes encoding the components of the type III secretion system borne on the locus of enterocyte effacement pathogenicity island. V erocytotoxin (VT)-producing Escherichia coli (VTEC) O157is a zoonotic pathogen causing food-borne disease outbreaks and sporadic cases of disease worldwide (1, 2). The symptoms induced upon VTEC O157 infection include a variety of clinical manifestations, such as diarrhea, hemorrhagic colitis, and the lifethreatening hemolytic-uremic syndrome (HUS). VTEC O157 can be found as a component of the intestinal microflora in numerous animal species, but domestic ruminants, especially cattle, have been identified as its main reservoir (2). The presence of VTEC O157 in the intestinal content of cattle may cause the contamination of food of bovine origin at the slaughterhouse (3, 4). Moreover, healthy cattle shed VTEC O157 in their feces, contaminating the farm environment and favoring its persistence in the herd (5-7).Although the main vehicle of infection is contaminated food of animal origin, the dispersion of VTEC O157 in the environment, caused by its elimination with ruminants' feces, also poses a risk for humans to acquire the infection. In particular, human infection can result from exposure to contaminated water, used either for drinking or for recreational purposes, as well as from consuming vegetables grown in fields irrigated with contaminated water or fertilized with animal manure not properly matured (8,9).The pathogenicity of VTEC O157 relies upon the expression of at least two key virulence features: the production of verocytotoxins (VTs), also termed Shiga toxins (Stxs), encoded by genes carried by temperate bacteriophages (10), and the induction of the characteristic attaching and effacing (A/E) lesion in the intestinal muco...

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“…The phage typing have become the most commonly used and the only internationally standardized subtyping method for STEC O157 (Allison et al, 2000;Mora et al, 2004). Unfortunately, we were unable to type our strains during analyses due to the lack of phages.…”

Section: Discussionmentioning

confidence: 99%

Presence and characteristics of sorbitol-negative Escherichia coli O157 in healthy sheep faeces

Türütoğlu¹,

Öztürk²,

Güler³

et al. 2007

Vet. Med.

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ABSTRACT:The presence of sorbitol-negative Escherichia coli O157 was investigated in healthy Awassi sheep faeces from 175 randomly selected animals in Burdur province of Turkey. Out of 175 animals, 16 (9.1%) were faecal shedding of sorbitol-negative E. coli O157. Out of the 15 flocks included in the study, 7 (47%) had at least one sheep positive for sorbitol-negative E. coli O157. The isolation rate of sorbitol-negative E. coli O157 ranged from 8.3 to 60% among the animals tested in the flocks. A total of 16 ovine sorbitol-negative E. coli O157 strains were characterized by a multiplex PCR. Results showed that 6 (37.7%) strains carried stx1 gene, 3 (18.8%) stx2 gene and 1 (6.3%) both stx1 and stx2 genes. Intimin (eaeA) gene was detected in 4 (25%) of the strains. None of the strains encoding for stx genes was positive for eaeA gene. The results demonstrate that the majority of sorbitol-negative E. coli O157 strains (62.5%) isolated from Awassi sheep in Burdur province of Turkey are Shiga toxin-producing E. coli that have a potential as human pathogens.

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Phage Types and Genotypes of Shiga Toxin-Producing Escherichia coli O157:H7 Isolates from Humans and Animals in Spain: Identification and Characterization of Two Predominating Phage Types (PT2 and PT8)

Cited by 47 publications

References 63 publications

Cytolethal Distending Toxin in Escherichia coli O157:H7: Spectrum of Conservation, Structure, and Endothelial Toxicity

Cytolethal Distending Toxin in Escherichia coli O157:H7: Spectrum of Conservation, Structure, and Endothelial Toxicity

Identification and Characterization of a Peculiar vtx2 -Converting Phage Frequently Present in Verocytotoxin-Producing Escherichia coli O157 Isolated from Human Infections

Presence and characteristics of sorbitol-negative Escherichia coli O157 in healthy sheep faeces

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