Phenotypic and Genotypic Detection of UV-induced Bacteriocin Production in Enteric Gram-Negative Rods and their Activity against Escherichia coli O157: H7

Background: Virulence and antibiotic resistance of bacterial pathogens are one of the most universal threats to public health care.  Materials: In this study, a total of two hundred and fifty-seven (257) enteric bacteria isolated from human rectal swabs and cattle dung were screened for production of low-toxic, high target-specific bactericidal macromolecule peptides (Bacteriocin) against strains of E. coli 0157: H7 using agar well diffusion method. The producer isolates were exposed to ultra-violet (UV) rays (UV 302nm and 254nm) for induction. Results: Out of the 257 isolates, 21 (8.1%) were active against E. coli 0157: H7 due to their constitutive bacteriocin, however, on the induction by UV ray; only 7 (2.1%) retained their potency for bacteriocin production. Three (42.9%) of seven isolates were randomly selected for genotypic screening (Col 28b (L) and Col K genes) because of their increased zone of inhibition (bioactive ability) after exposure to UV ray; the isolates also showed resistance to ≤ 2 classes of antibiotics and exhibited Gamma/alpha haemolysis. Conclusion: This study revealed Serratia marcescens in this work to possess an antimicrobial molecule of bacteriocinogenic type with possession of Col 28b gene.