ISOLATION AND PHYSICOCHEMICAL CHARACTERIZATION OF LYTIC BACTERIOPHAGES AGAINST MULTI-DRUG-RESISTANT PSEUDOMONAS AERUGINOSA FROM HOSPITAL SEWAGE SAMPLE

Abstract

The rapid emergence of antibiotics resistance has become one of the most pressing global health challenges with Pseudomonas aeruginosa recognized as leading cause of health care associated infections and multi-drug resistant bacterial infections. Bacteriophages have gained attention as a potential alternative to conventional antibiotics. This study aimed to isolate and characterize lytic bacteriophages against MDR P. aeruginosa from hospital sewage samples (n=25), were collected from Okara and Sahiwal region, Pakistan. Two isolated bacteriophages designated as P. a Ø and P. a Ø1 were selected for characterization. The phages exhibited titer of 3×1012 PFU/mL and 2×1010 PFU/mL, respectively, and produced a clear plaque measuring 1.2 - 1.5 mm in diameter. Host range analysis demonstrated that both the phages were highly specific to MDR P. aeruginosa. Latent period of isolated phages P. a Ø and P. a Ø1 were approximately 25 minutes and the burst size of 154 PFU/infected cell and 118 virus particles released per infected cell. Physicochemical characterization showed that both the phages remain stable over a pH range of 3-11 and temperature range of 70°C while reduced viability or complete inactivation at 80°C. No detectable activity was found against the ethanol exposure (63%) and acetone (90%). A decreased stability was observed against normal saline and chloroform (70%). In addition, both the bacteriophages retained viability during storage at 4°C and -20°C for time up to three months, although the gradual decline in the titer was observed. The findings of this study provide foundation for in vitro and in vivo investigations to evaluate the therapeutically potential of these bacteriophages against multi-drug resistant P. aeruginosa.