Isolation and genomic characterization of drug-resistant Pseudomonas aeruginosa and its phage from Iraqi hospital wastewater

Abstract

Pseudomonas aeruginosa can develop resistance to antibiotics and tolerance to antimicrobials. Bacteriophages have been proposed as an alternative strategy for eliminating pathogens, but they require further genetic studies. Therefore, this study aimed to isolate a bacteriophage from hospital wastewater, examine its biological properties, and analyze the genomes of both the host bacterium and bacteriophage. A bacteriophage was isolated from hospital wastewater, purified, and amplified. The optimal temperature range was 20°C–37°C, with an optimal pH of 7 and multiplicity of infection of 1. The bacteriophage exhibited growth inhibition against 24% of P. aeruginosa clinical isolates. The host bacterium genome spanned 104 contigs, with an estimated total length of 6,455,470 bp and GC content of 66.27% and contained five prophage regions. Draft genome assembly of the phage consisted of nine contigs totalling 94,292 bp of double-stranded DNA. It contained 158 open reading frames, none of which encoded virulence or antibiotic resistance genes, but one encoded a transfer RNA. Whole-genome sequence comparison using BLASTn showed approximately 99% nucleotide identity with Pseudomonas phage Samunavirus SM1. Our study represents the first genomic report of an SM1-like bacteriophage and its host isolated from hospital wastewater in Iraq.