Characterization and Genomic Analysis of a New Bacteriophage Klebsiella pneumoniae CTF-1 from Turkey

<b>Background/Objectives:</b><i>Klebsiella pneumoniae</i> is a clinically important pathogen that causes respiratory tract infections, pneumonia, wound infections, urinary tract infections, and sepsis. It is on the World Health Organization (WHO) priority pathogen list as it causes antimicrobial-resistant infections. The aim of this study was to isolate bacteriophages against pan-resistant <i>K. pneumoniae</i> isolated from clinical wound infections. <b>Results:</b> One of the isolated phages, CTF-1, possesses a linear double-stranded DNA genome that is 40,841 base pairs (bp) long and contains 44 predicted genes. Functional assignments were made for 31 of the predicted gene products, which are associated with genome replication, phage packaging, structural proteins, and host lysis, leaving 13 annotated as hypothetical proteins. Based on sequencing analysis, phage CTF-1 is a new member of the genus <i>Przondovirus</i> within the order <i>Autographivirales</i>. Phage CTF-1 was effective against 22 of 25 (88%) pan-resistant <i>K. pneumoniae</i> isolates. The latent period and lytic cycle of the phage were approximately 40 min, with a burst size of about 92 PFU/mL. <b>Conclusions:</b> Our findings suggest that <i>Klebsiella</i> phage CTF-1 is an excellent candidate for phage therapy due to its high lytic activity against pan-resistant <i>K. pneumoniae</i> strains and lack of genes encoding antibiotic resistance, toxins, virulence factors, or integrases.