Supporting data for "Isolation and characterization of phages from environmental sources"

This research aims to screen potential phage candidates from available commercial product mixture and from Hong Kong local sewage samples. Both S. aureus and the pathogenic E. coli strains representing the Gram positive and Gram negative bacterial strains that confers severe infections on human were employed for the hosts in the screening. The potential phages were isolated from monitoring bacterial growth. The bacterial growth was monitored by real-time kinetic assay using spectrophotometric method to determine the optical density of the bacteria. The selected phages were amplified and purified prior to subsequent characterizations, including the phage profiling on host susceptibility test, one-step growth curve to determine the latent periods (duration for activation of phage) and burst sizes (the productivity upon effective phage lysis, titre determination and electron microscopic study for morphogenetic examination and demonstrating host selectivity. To evaluate the effectiveness on live animals, transurethral administration of coliphage B6W was employed to investigate the in vivo efficacy of host clearance on uropathogenic strain, CFT-073. To broaden the host range of phage, Appelmans' protocol was carried out on S. aureus phages to yield mutant or evolved phages (descendant es phages. The genomes of evolved phages were obtained from Nanopore sequencing. Through comparative genomic studies, the evolutionary relationship was illustrated by the plot of phylogenetic diagram on both parental (ancestral) phages and descendant phages.