Isolation and characterisation of Pseudomonas aeruginosa bacteriophage isolated from Batu Pahat, Johor, Malaysia

Abstract

The World Health Organization has classified Pseudomonas aeruginosa as a 'Priority One and Critical Pathogen' for which research and design of new antibiotics are urgently needed due to its high rate of antimicrobial resistance. Phage therapy, which uses bacteriophages (phages), has been proposed as an antibacterial agent and shows potential for combating this issue. This study aimed to isolate and characterise bacteriophages from different environmental samples that act specifically against P. aeruginosa. The phages were tested to determine their ability to lyse P. aeruginosa using a spot test. Transmission electron microscopy (TEM) was employed to determine the structure, size and phage family, while specificity and sensitivity tests were conducted using six different bacterial species and 20 clinical multi-drug resistant P. aeruginosa isolates, respectively. Phage PA1 was isolated from Batu Pahat, Johor and using a spot test, PA1 could form clear plaques against P. aeruginosa. PA1 was present in a high titer of 1.06 (± 32.2) x 1010 PFUs/ml. Based on TEM analysis, PA1 was classified as a member of the Myoviridae family. Host-range analysis displayed that PA1 had 100% specificity towards P. aeruginosa and only 45% sensitivity towards different P. aeruginosa clinical isolates. Phage PA1 demonstrated lysis of P. aeruginosa but exhibited a narrow host range, presenting a challenge for phage therapy. A promising approach to overcome this limitation involves using phage cocktails containing multiple strains of phages to broaden the host range and enhance the overall efficacy of phage therapy.