Probiotic Potential of Autochthonous Lactobacillus against Avian Pathogenic Escherichia coli

Background: The aim of current study was to investigate the probiotic potential of autochthonous Lactobacillus species against pathogenic Escherichia coli in poultry. Method: A total of 73 samples were collected from cloacal swabs and tissues of desi and commercial chicken. The Lactobacillus were isolated based on cultural, biochemical and molecular teats. The probiotic potency was tested in vitro and antimicrobial activity and ABST was carried by Agar well diffusion and disc diffusion methods, respectively. Nucleotide sequencing was done by Sanger sequencing. Haemolysis and gelatin hydrolysis assays were used as safety testes. Result: From 73 cloacal swabs and tissues of desi and commercial chicken, 56 Lactobacillus were isolated of which 22 showed high autoaggregation and hydrophobicity potential. Based on survivability at acidic pH (2.5) and bile concentrations (0.5%), 16 isolates were selected and were subjected to well diffusion assay against pathogenic E. coli. All the isolates showed zone of inhibition against E. coli ranging from 10 -18 mm. ABST revealed that all the isolates are sensitive to chloramphenicol, ampicillin and erythromycin and 75% of the isolates were resistant to streptomycin, gentamicin and vancomycin. Only one isolate out of 16 tested was non hemolytic and none of the isolates tested positive for gelatine hydrolysis. Sequencing result of selected isolate revealed 96.82% of its similarity to Lactobacillus fermentum.