Antibiofilm efficacy and genomic characterization of a lytic bacteriophage targeting MDR uropathogenic Escherichia coli.

Uropathogenic Multidrug-resistant Escherichia coli is a leading cause of persistent urinary tract infections, largely because of its ability to form antibiotic-tolerant biofilms. Isolation of bacteriophage UHEC was carried out from hospital sewerage utilizing a third-generation cephalosporin-resistant E. coli clinical isolate EC-11. The phage was characterized by plaque morphology, host range, growth kinetics, environmental stability, planktonic growth inhibition, and biofilm removal capacity. Genome sequencing and bioinformatic analyses were done to assess genomic traits, safety, and phylogeny placement. UHEC formed small, clear plaques and exhibited a narrow host range limited to selected E. coli clinical isolates. In planktonic cultures, UHEC produced rapid and dose-dependent growth suppression. UHEC demonstrated pronounced anti-biofilm activity against EC-11 biofilms at different stages of maturation. Treatment of 24- and 48-h-old biofilms resulted in 3.3-3.8 log reductions after 24 h of exposure, corresponding to > 99.9% reduction compared with untreated controls. Although reduced efficacy was observed against more mature biofilms (72-96 h), extended phage exposure still produced statistically significant reductions of up to 0.9 log. UHEC remained stable across pH ranges of 6-9, moderate temperatures, and long term storage at 4 °C and -80 °C. UHEC has a latency period of 25 min with average burst size of 112 PFU/cell. Genomic analysis identified a 58.8 kbp double-stranded DNA genome lacking lysogeny, virulency, or antimicrobial resistance gene. Phylogenetic analyses placed UHEC among T7-like lytic bacteriophages within the class Caudoviricetes. Conclusively, UHEC is a genetically safe, lytic bacteriophage with notable anti-biofilm activity against MDR uropathogenic E. coli, supporting its potential utility in future preclinical investigations.