In silico analysis of tkt1 from avian pathogenic Escherichia coli and its virulence evaluation in chickens
Department of Biosystems, Faculty of Bioscience Engineering, University of Leuven (KU Leuven), Kasteelpark Arenberg 30, B-3001 Heverlee, Belgium; Department of Veterinary Microbiology and Parasitology, Sokoine University of Agriculture, P.O. Box 3019, ChuoKikuu, Morogoro, Tanzania
Extraintestinal pathogenic Escherichia coli (ExPEC) contain tktA and tktB which code for transketolases involved in the pentose phosphate pathway. Recent studies demonstrated that a third gene coding for transketolase 1 (. tkt1) was located in a pathogenicity island of avian and human ExPEC belonging to phylogenetic group B2. In the present study, in silico analysis of tkt1 revealed 68% and 69% identity with tktA and tktB, respectively, of ExPEC and 68% identity with tktA and tktB of E. coli MG1655. The translated tkt1 shared 69% and 68% identity with TktA and TktB proteins, respectively, of ExPEC and E. coli MG1655. Phylogenetically, it is shown that the three genes (. tktA, tktB and tkt1) cluster in three different clades. Further analysis suggests that tkt1 has been acquired though horizontal gene transfer from plant-associated bacteria within the family Enterobacteriaceae. Virulence studies were performed in order to evaluate whether tkt1 played a role in avian pathogenic E. coli CH2 virulence in chickens. The evaluation revealed that mutant virulence was slightly lower based on LD50 when compared to the wild type during infection of chickens, but there were no significant differences when the two strains were compared based on the number of deaths and lesion scores. © 2013 Institut Pasteur.
protein; tkt1 protein; unclassified drug; article; avian pathogenic Escherichia coli; bacterial virulence; chicken; Enterobacteriaceae; horizontal gene transfer; LD 50; nonhuman; phylogeny; priority journal; Animals; Chickens; Cluster Analysis; DNA, Bacterial; Escherichia coli; Escherichia coli Infections; Escherichia coli Proteins; Genomic Islands; Lethal Dose 50; Molecular Sequence Data; Phylogeny; Sequence Analysis, DNA; Sequence Homology, Amino Acid; Survival Analysis; Transketolase; Virulence; Virulence Factors; Aves; Enterobacteriaceae; Escherichia coli; Gallus gallus