LAUSR

Colicinogenic E.coli in the gut of human and animal are known to battle pathogen accumulation in the gut and in this manner, shielding them from severe diseases. The ability of commensal E.coli, from human and animals, to restrain Gram negative pathogens was evaluated in-vitro. Approximately 13.2% of E.coli isolates inhibited the growth of target pathogens. Maximum inhibition was observed against E.coli O157:H7 (36%) followed by 35%, 27%, 24% and 13% inhibition against E.coli O26:H11, Pseudomonas aeruginosa, Salmonella enterica and Klebsiella pneumoniae, respectively. Detection of 20 colicin determinants in colicinogenic E.coli revealed that >50% isolates exhibited multiple colicins genes. Among all isolates, 70.4% E.coli were possessing col E6 gene followed by col Ib (66.4%), E4 (53.6%), E7 (49.9%), J (35.3%) and 35.2% M determinants. The frequency of col D (8.8%), Ia (27.9%), S4 (12%), E3 (13.2%) and E9 (2.9%) was greater in human samples as compared to cow and sheep, whereas, col10 (5.8%) and E5 (4.4%) were produced by only cow derived E.coli. Colicinogenic E.coli belonging to phylogenetic group B2 (52.8%) were more prevalent following D1 (16%), B1 (13.2%), A1 (11.6%) and A0 (5.8%). The 16SrRNA sequencing of all colicinogenic E.coli provided 27 non-clinical variants of E.coli which can be further explored for their probiotic properties to minimize risk of gut diseases.