Efficacy of Lytic Bacteriophages Isolated from Waste Dumpsites in Southwestern Uganda Against Carbapenem-Resistant P. aeruginosa AND E. coli
Loading...
Date
2023-05
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Kampala International University
Abstract
The escalating rate of infections due to carbapenem resistant bacteria has led to a revived interest in compassionate use of phage therapy either as a substitute or supplement to conventional antibiotics. The present study aimed at characterizing and determining the lytic efficacy of bacteriophage isolates from selected waste dump sites in Southwestern Uganda against carbapenem-resistant (CR) P. aeruginosa and E. coli. A laboratory experimental study design was conducted. Eighteen samples (soil and leachate) were collected from 3 selected waste dump sites (Kekombe, Kabagarame and Kidodo waste dumpsites). Phage isolation was done using the double agar overlay plaque technique and their lytic activity against CR P. aeruginosa and E. coli was determined using both spot and in vitro therapeutic inhibition assays. Physico-chemical and biological characterization of efficacious phages was done. The phage cocktail (1:1) was assayed for biofilm inhibitory efficacy. Sixteen lytic phages against CR P. aeruginosa and E. coli were identified. Only four (04) phages; KA06ph03KA, KA01C, BU03B, and KE01E exhibited high virulence with mean efficiency of plating (EOP) of 0.169–0.552) and broad-spectrum of activity. These phages produced clear pin point to small sized plaques (0.1 - 1 mm diameter) and formed turbid haloes on E. coli hosts. These phages had short latent periods (5–20 minutes), short adsorption times (5–15 min), variable burst sizes (21–101 PFU/infected cell) and burst times (25–85 min). Their thermal stability ranged between -20°C to 60°C except phages KA01C and KA06ph03KA that retained stability at both 70°C and 80°C for 10 min and shared pH stability range of 2 to 10. The phage cocktail exhibited maximal inhibitory effects within 2 to 3 hours as compared to individual phages. Even so, it was more effective in treating the planktonic cells and 24 hr old biofilms of CR P. aeruginosa and E. coli. The studied waste dumpsites harbored virulent lytic phages against CR P. aeruginosa and E. coli and the phage cocktail had better therapeutic potential over individual phages. The study therefore recommends molecular characterization and in vivo efficacy testing of the isolated in order to ascertain their safety for therapeutic usage in humans as well as use of phage cocktail as opposed to individual phages.