Phylogrouping of Escherichia coli strains from colibacillosis affected chicken
Author(s): Punit Jhandai, Dinesh Mittal, Renu Gupta and Manesh Kumar
Abstract: Avian colibacillosis, caused by avian pathogenic Escherichia coli (APEC), contributes significantly to economic losses within the poultry sector, including mortality, morbidity, and carcass condemnation. Various strains of E. coli, categorized into different phylogroups, possess unique genetic and phenotypic characteristics that influence their ability to cause disease. Present study was undertaken to determine the phylogroups of Escherichia coli isolates isolated from colibacillosis affecting poultry. Tissue samples were collected from poultry flocks exhibiting typical colibacillosis lesions like pericarditis, perihepatitis, air sacculitis etc. In this study, 50 E. coli isolates, consisting of 45 APEC and 5 non-APEC isolates, were categorized into phylogroups. The primer pairs yjaA, chuA, arpA, TspE4.C2 and trpA were utilized for PCR to amplify specific fragments, enabling phylogenetic typing. The results classified E. coli isolates (n=50) into B1 (31%), A (28%), B2 (10%), F (6%) and D (4%). Four E. coli isolates (8%) could not be classified or were of unknown type, and none of the E. coli isolates fell into phylogroup C. Approximately 6% of the E. coli isolates were assigned to either Clade I or Clade II. The research showed that phylogroup B1 is prevalent in E. coli found in colibacillosis-infected poultry in Haryana. The presence of unidentified phylogroups emphasizes further investigation in the protocols and techniques used for phylogrouping. This might suggest possibility for discovering new phylogroups.
