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Virulence genes, Shiga toxin subtypes, major O-serogroups, and phylogenetic background of Shiga toxin-producing Escherichia coli strains isolated from cattle in Iran.
Microb Pathog. 2017 Aug; 109:274-279.MP

Abstract

The aim of this study was to investigate the virulence potential of the isolated bovine STEC for humans in Iran. In this study a collection of STEC strains (n = 50) had been provided via four stages, including sampling from feces of cattle, E. coli isolation, molecular screening of Shiga toxin (stx) genes, and saving the STEC strains from various geographical areas in Iran. The STEC isolates were subjected to stx-subtyping, O-serogrouping, and phylo-grouping by conventional polymerase chain reaction (PCR). Occurrence of stx1 (52%) and stx2 (64%) was not significantly different (p = 0.1), and 16% of isolates carried both stx1 and stx2, simultaneously. In addition, 36% and 80% of the isolates were positive for eae and ehxA, respectively. Molecular subtyping showed that stx1a (52%), stx2a (44%), stx2c (44%), and stx2d (30%) were the most prevalent subtypes; two combinations stx2a/stx2c and stx2c/stx2d coexisted in 18% and 10% of STEC strains, respectively. Three important non-O157 serogroups, including O113 (20%), O26 (12%), and O111 (10%), were predominant, and none of the isolates belonged to O157. Importantly, one O26 isolate carried stx1, stx2, eae and ehxA and revealed highly virulent stx subtypes. Moreover, all the 21 serogrouped strains belonged to the B1 phylo-type. Our study highlights the significance of non-O157 STEC strains carrying highly pathogenic virulence genes in cattle population as the source of this pathogen in Iran. Since non-O157 STEC strains are not routinely tried in most diagnostic laboratories, majority of the STEC-associated human infections appear to be overlooked in the clinical settings.

Authors+Show Affiliations

Applied Microbiology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran.Applied Microbiology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran.Department of Pathobiology, Faculty of Veterinary Medicine, Garmsar Branch, Islamic Azad University, Garmsar, Iran.Applied Microbiology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran. Electronic address: ahmadi1919@gmail.com.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

28578089

Citation

Jajarmi, Maziar, et al. "Virulence Genes, Shiga Toxin Subtypes, Major O-serogroups, and Phylogenetic Background of Shiga Toxin-producing Escherichia Coli Strains Isolated From Cattle in Iran." Microbial Pathogenesis, vol. 109, 2017, pp. 274-279.
Jajarmi M, Imani Fooladi AA, Badouei MA, et al. Virulence genes, Shiga toxin subtypes, major O-serogroups, and phylogenetic background of Shiga toxin-producing Escherichia coli strains isolated from cattle in Iran. Microb Pathog. 2017;109:274-279.
Jajarmi, M., Imani Fooladi, A. A., Badouei, M. A., & Ahmadi, A. (2017). Virulence genes, Shiga toxin subtypes, major O-serogroups, and phylogenetic background of Shiga toxin-producing Escherichia coli strains isolated from cattle in Iran. Microbial Pathogenesis, 109, 274-279. https://doi.org/10.1016/j.micpath.2017.05.041
Jajarmi M, et al. Virulence Genes, Shiga Toxin Subtypes, Major O-serogroups, and Phylogenetic Background of Shiga Toxin-producing Escherichia Coli Strains Isolated From Cattle in Iran. Microb Pathog. 2017;109:274-279. PubMed PMID: 28578089.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Virulence genes, Shiga toxin subtypes, major O-serogroups, and phylogenetic background of Shiga toxin-producing Escherichia coli strains isolated from cattle in Iran. AU - Jajarmi,Maziar, AU - Imani Fooladi,Abbas Ali, AU - Badouei,Mahdi Askari, AU - Ahmadi,Ali, Y1 - 2017/05/31/ PY - 2017/04/05/received PY - 2017/05/29/revised PY - 2017/05/30/accepted PY - 2017/6/5/pubmed PY - 2018/3/3/medline PY - 2017/6/5/entrez KW - Cattle KW - Phylogenetic KW - Serogroup KW - Shiga toxin-producing E. coli (STEC) KW - Subtype SP - 274 EP - 279 JF - Microbial pathogenesis JO - Microb Pathog VL - 109 N2 - The aim of this study was to investigate the virulence potential of the isolated bovine STEC for humans in Iran. In this study a collection of STEC strains (n = 50) had been provided via four stages, including sampling from feces of cattle, E. coli isolation, molecular screening of Shiga toxin (stx) genes, and saving the STEC strains from various geographical areas in Iran. The STEC isolates were subjected to stx-subtyping, O-serogrouping, and phylo-grouping by conventional polymerase chain reaction (PCR). Occurrence of stx1 (52%) and stx2 (64%) was not significantly different (p = 0.1), and 16% of isolates carried both stx1 and stx2, simultaneously. In addition, 36% and 80% of the isolates were positive for eae and ehxA, respectively. Molecular subtyping showed that stx1a (52%), stx2a (44%), stx2c (44%), and stx2d (30%) were the most prevalent subtypes; two combinations stx2a/stx2c and stx2c/stx2d coexisted in 18% and 10% of STEC strains, respectively. Three important non-O157 serogroups, including O113 (20%), O26 (12%), and O111 (10%), were predominant, and none of the isolates belonged to O157. Importantly, one O26 isolate carried stx1, stx2, eae and ehxA and revealed highly virulent stx subtypes. Moreover, all the 21 serogrouped strains belonged to the B1 phylo-type. Our study highlights the significance of non-O157 STEC strains carrying highly pathogenic virulence genes in cattle population as the source of this pathogen in Iran. Since non-O157 STEC strains are not routinely tried in most diagnostic laboratories, majority of the STEC-associated human infections appear to be overlooked in the clinical settings. SN - 1096-1208 UR - https://www.unboundmedicine.com/medline/citation/28578089/Virulence_genes_Shiga_toxin_subtypes_major_O_serogroups_and_phylogenetic_background_of_Shiga_toxin_producing_Escherichia_coli_strains_isolated_from_cattle_in_Iran_ DB - PRIME DP - Unbound Medicine ER -