Isolation and Characterization of Lytic Bacteriophages from Various Sources in Addis Ababa Against Antimicrobial Resistant Diarrheagenic E. Coli Strains and Evaluate their Therapeutic Potentials
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Date
2023-10
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Addis Ababa University
Abstract
Escherichia coli is a common fecal coliform, facultative aerobic, gram-negative bacterium. Pathogenic strains of such microbe have evolved to cause diarrhea, urinary tract infection and septicemias. The emergences of antibiotic-resistance urged to find an alternative strategy. The use of lytic bacteriophages against the control of pathogenic E. coli in the clinics and different environmental setups (waste and drink water management) become an alternative therapy to antibiotic therapy. Thus, this study aimed to isolate and characterize the lytic bacteriophage from various sources in Addis Ababa and tested against antimicrobial resistant diahrrgenic E. coli strains and evaluates their therapeutic potentials under invitro conditions. A total of 14 samples were processed against six different diahrrgenic E. coli strains. Conventional culture and plaque analysis agar overlay method was conducted to recover lytic bacteriophage isolates. The phage isolates were characterized to determine their lytic effect, growth characteristics, host range activity and stability under different temperature and pH conditions. Phage isolates were identified by Scanning Electron Microscope (SEM), molecular techniques (PCR), and whole genome sequencing. Totally, 17 phages were recovered from 84 tested plates. Totally, 17 phages were recovered from 84 tested plates. Of the 17 phage isolates, 11(65%) were Myoviridae-like phages, 6 (35%) phage isolates were Podoviridae and Siphoviridae by morphology and PCR identification. Bacteriophage genome sequencing revealed that each bacteriophage has a linear double-stranded DNA genome. The GC content of phage genomes ranged from 43 to 54%, while their sizes ranged from 40,427 to 143,710 bp. The whole genome sequence analysis of 7 potent coliphages showed that phage isolates were taxonomically classified as 4 (57%) of Myoviridae phages and 3 (43%) of Siphoviridae phages. Based on the host range test, growth characteristics and stability test 7 potent phages were selected. These phages demonstrated better growth characteristics, including short latent periods, highest burst sizes, and wider host ranges, as well as thermal stability and the ability to survive in a wide range of pH levels. These phages' promising effect against AMR pathogens has raised the possibility of their use in biological control of bacterial infections.
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Lytic Bacteriophages, Diahrrgenic E. Coli, Myoviridae, Siphoviridae, Podoviridae