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Experimental mouse lethality of Escherichia coli strains isolated from free ranging Tibetan yaks
- Rehman, Mujeeb Ur, Zhang, Hui, Wang, Yajing, Mehmood, Khalid, Huang, Shucheng, Iqbal, Muhammad Kashif, Li, Jiakui
- Microbial pathogenesis 2017 v.109 pp. 15-19
- Escherichia coli, animal models, farmers, feces, genes, humans, mice, mortality, pathotypes, phylogeny, risk, serotypes, virulence, yaks
- The present study has examined the virulence potential of Escherichia coli isolates harboring at least one virulence gene (associated with ExPEC or InPEC pathotype and belonging to different phylogenetic groups: A, B1, B2 or D), isolated from free ranging Tibetan yak feces. The E. coli isolates (n = 87) were characterized for different serogroups and a mouse model of subcutaneous–infection was used to envisage the virulence within these E. coli strains. Of the 87 E. coli isolates examined, 23% of the E. coli isolates caused lethal infections in a mouse model of subcutaneous infection and were classified as killer. Moreover, the majority of the killer strains belonged to phylogroup A (65%) and serogroup O60 or O101 (35%). Phylogroup B1, serogroups O60 and O101 were statistically associated with the killer status (P < 0.05). However, positive associations (OR >1) were observed between the killer status isolates and all other bacterial virulence traits. This study comprises the first report on the virulence potential of E. coli strains isolated from free-ranging Tibetan yaks feces. Our findings suggest that pathogenic E. coli of free ranging yaks is highly worrisome, as these feces are used as manures by farmers and therewith pose a health risk to humans upon exposure.