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Identification of genetic markers for differentiation of Shiga toxin-producing, enteropathogenic, and avirulent strains of Escherichia coli O26.
Appl Environ Microbiol. 2011 Apr; 77(7):2275-81.AE

Abstract

Shiga toxin-producing Escherichia coli (STEC) O26 is one of the top five enterohemorrhagic E. coli (EHEC) O groups most often associated with hemorrhagic colitis and hemolytic uremic syndrome (HUS) worldwide. STEC O26 is considered to have evolved from enteropathogenic (EPEC) O26 strains through the acquisition of Shiga toxin (Stx)-encoding genes. Our PCR data identified several STEC-like strains expressing all features of STEC except Stx production and carrying remnants of Stx phages that were probably derivatives of EHEC O26. EHEC and EPEC O26 strains phenotypically resemble O26 EHEC-like and apathogenic E. coli O26 strains and are therefore undistinguishable by cultural methods. A clear discrimination between the different O26 groups is required for diagnostics in patients and for control of food safety. To develop an assay for specific detection of EHEC and EHEC-like O26 strains, we used a high-throughput PCR approach for selection of discriminative genetic markers among 33 tested genes mostly encoding type III secretion system effector proteins. The genes ECs1822, nleH1-2, nleA, nleC, nleH1-1, nleG, nleG2, nleG6-1, nleG6-2, espJ, espM2, nleG8-2, espG, ent (or espL2), nleB, nleE, efa1, and espB were detected at different frequencies in O26 EHEC, EHEC-like, and EPEC strains, indicating the possible role of these genes in virulence of human pathogenic O26 strains. The espK and espN genes were detected only in EHEC and EHEC-like O26 strains. espK was present in 99.14% of EHEC and 91.14% of EHEC-like O26 strains and was hence the best candidate as a genetic marker for characterizing these pathogroups. These data were corroborated by a genotyping real-time PCR test based on allelic discrimination of the arcA (aerobic respiratory control protein A) gene. The results indicate that a combination of molecular detection tools for O26 wzx (wzx(O26)), eae-beta, stx, espK, and arcA genotyping is highly discriminative for clear identification of EHEC and EHEC-like E. coli O26 strains. This simple diagnostic test might be applicable in hospital service laboratories or public health laboratories to test strains isolated from stools of patients suffering from diarrhea.

Authors+Show Affiliations

French Agency for Food, Environmental and Occupational Health (Anses), Food Safety Laboratory, 23 Av. du Général De Gaulle, Fr-94706 Maisons-Alfort, France.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

21317253

Citation

Bugarel, Marie, et al. "Identification of Genetic Markers for Differentiation of Shiga Toxin-producing, Enteropathogenic, and Avirulent Strains of Escherichia Coli O26." Applied and Environmental Microbiology, vol. 77, no. 7, 2011, pp. 2275-81.
Bugarel M, Beutin L, Scheutz F, et al. Identification of genetic markers for differentiation of Shiga toxin-producing, enteropathogenic, and avirulent strains of Escherichia coli O26. Appl Environ Microbiol. 2011;77(7):2275-81.
Bugarel, M., Beutin, L., Scheutz, F., Loukiadis, E., & Fach, P. (2011). Identification of genetic markers for differentiation of Shiga toxin-producing, enteropathogenic, and avirulent strains of Escherichia coli O26. Applied and Environmental Microbiology, 77(7), 2275-81. https://doi.org/10.1128/AEM.02832-10
Bugarel M, et al. Identification of Genetic Markers for Differentiation of Shiga Toxin-producing, Enteropathogenic, and Avirulent Strains of Escherichia Coli O26. Appl Environ Microbiol. 2011;77(7):2275-81. PubMed PMID: 21317253.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Identification of genetic markers for differentiation of Shiga toxin-producing, enteropathogenic, and avirulent strains of Escherichia coli O26. AU - Bugarel,Marie, AU - Beutin,Lothar, AU - Scheutz,Flemming, AU - Loukiadis,Estelle, AU - Fach,Patrick, Y1 - 2011/02/11/ PY - 2011/2/15/entrez PY - 2011/2/15/pubmed PY - 2011/7/19/medline SP - 2275 EP - 81 JF - Applied and environmental microbiology JO - Appl Environ Microbiol VL - 77 IS - 7 N2 - Shiga toxin-producing Escherichia coli (STEC) O26 is one of the top five enterohemorrhagic E. coli (EHEC) O groups most often associated with hemorrhagic colitis and hemolytic uremic syndrome (HUS) worldwide. STEC O26 is considered to have evolved from enteropathogenic (EPEC) O26 strains through the acquisition of Shiga toxin (Stx)-encoding genes. Our PCR data identified several STEC-like strains expressing all features of STEC except Stx production and carrying remnants of Stx phages that were probably derivatives of EHEC O26. EHEC and EPEC O26 strains phenotypically resemble O26 EHEC-like and apathogenic E. coli O26 strains and are therefore undistinguishable by cultural methods. A clear discrimination between the different O26 groups is required for diagnostics in patients and for control of food safety. To develop an assay for specific detection of EHEC and EHEC-like O26 strains, we used a high-throughput PCR approach for selection of discriminative genetic markers among 33 tested genes mostly encoding type III secretion system effector proteins. The genes ECs1822, nleH1-2, nleA, nleC, nleH1-1, nleG, nleG2, nleG6-1, nleG6-2, espJ, espM2, nleG8-2, espG, ent (or espL2), nleB, nleE, efa1, and espB were detected at different frequencies in O26 EHEC, EHEC-like, and EPEC strains, indicating the possible role of these genes in virulence of human pathogenic O26 strains. The espK and espN genes were detected only in EHEC and EHEC-like O26 strains. espK was present in 99.14% of EHEC and 91.14% of EHEC-like O26 strains and was hence the best candidate as a genetic marker for characterizing these pathogroups. These data were corroborated by a genotyping real-time PCR test based on allelic discrimination of the arcA (aerobic respiratory control protein A) gene. The results indicate that a combination of molecular detection tools for O26 wzx (wzx(O26)), eae-beta, stx, espK, and arcA genotyping is highly discriminative for clear identification of EHEC and EHEC-like E. coli O26 strains. This simple diagnostic test might be applicable in hospital service laboratories or public health laboratories to test strains isolated from stools of patients suffering from diarrhea. SN - 1098-5336 UR - https://www.unboundmedicine.com/medline/citation/21317253/Identification_of_genetic_markers_for_differentiation_of_Shiga_toxin_producing_enteropathogenic_and_avirulent_strains_of_Escherichia_coli_O26_ L2 - http://aem.asm.org/cgi/pmidlookup?view=long&pmid=21317253 DB - PRIME DP - Unbound Medicine ER -