Characterization, Sequencing, and Phage Cocktail Evaluation of SR and NL Bacteriophages in BALB/c Mouse against Carbapenem resistant Acinetobacter baumannii

Abstract

Acinetobacter baumannii, has become a critical concern due to its high prevalence and death rates, coupled with its potential to develop resistance to multiple antibiotics including carbapenem. In a current study, two new bacteriophages SR and NL were isolated from wastewater, characterized in vitro and their therapeutic potential was assessed using mouse model of pneumonia. In vitro results showed that both phages can efficiently be adsorbed to host, robust lytic activity, have short latent period and high burst size. Sequence analysis showed that SR and NL phages have ds DNA genome of 45218 and 41230 base pairs with GC content of 38% and 37.9% and contain 87 and 85 coding sequences, respectively. TEM images and genomic analysis predicts that both phages belong to Myoviridae family. Complete genomic analysis confirms the absence of virulence genes, antimicrobial resistance genes and lysogenic genes, making them more perfect candidates for phage therapy. In vivo study showed high survival rate of mice treated with phage cocktail as compared to control group. In order to combat the pneumonia brought on by CRAB strains, our research investigates the possible application of phages as a substitute therapeutic agent.