Abstract:
Background: Antibiotic-resistant Pseudomonas aeruginosa (P. aeruginosa) is one of the most critical pathogens in
wound infections, causing high mortality and morbidity in severe cases. However, bacteriophage therapy is a poten‑
tial alternative to antibiotics against P. aeruginosa. Therefore, this study aimed to isolate a novel phage targeting P.
aeruginosa and examine its efcacy in vitro and in vivo.
Results: The morphometric and genomic analyses revealed that ZCPA1 belongs to the Siphoviridae family and could
infect 58% of the tested antibiotic-resistant P. aeruginosa clinical isolates. The phage ZCPA1 exhibited thermal stability
at 37 °C, and then, it decreased gradually at 50 °C and 60 °C. At the same time, it dropped signifcantly at 70 °C, and
the phage was undetectable at 80 °C. Moreover, the phage ZCPA1 exhibited no signifcant titer reduction at a wide
range of pH values (4–10) with maximum activity at pH 7. In addition, it was stable for 45 min under UV light with
one log reduction after 1 h. Also, it displayed signifcant lytic activity and bioflm elimination against P. aeruginosa by
inhibiting bacterial growth in vitro in a dose-dependent pattern with a complete reduction of the bacterial growth at
a multiplicity of infection (MOI) of 100. In addition, P. aeruginosa-infected wounds treated with phages displayed 100%
wound closure with a high quality of regenerated skin compared to the untreated and gentamicin-treated groups
due to the complete elimination of bacterial infection.
Conclusion: The phage ZCPA1 exhibited high lytic activity against MDR P. aeruginosa planktonic and bioflms. In
addition, phage ZCPA1 showed complete wound healing in the rat model. Hence, this research demonstrates the
potential of phage therapy as a promising alternative in treating MDR P. aeruginosa.
