Isolation and Characterization of Four New Coliphages against Extra Intestinal Pathogenic <i>Escherichia coli</i> Isolates Recovered from Cystic Fibrosis Patients

Cystic fibrosis (CF) is a common genetic disorder that significantly reduces life expectancy, particularly among Caucasians. It is caused by mutations in the CFTR protein, leading to thick mucus secretions that encourage microbial colonization, particularly in the lungs. While <i>Pseudomonas aeruginosa</i> and <i>Staphylococcus aureus</i> are well-established contributors to CF lung infections, recent research highlights a more diverse range of pathogens, including <i>Escherichia coli</i>, which is not typically considered a respiratory pathogen. In this study, we identified and characterized four new bacteriophages with lytic properties specifically targeting multidrug-resistant Extraintestinal Pathogenic <i>E. coli</i> strains isolated from CF patients. Phages were isolated from wastewater samples and tested for their lytic activity against a panel of <i>E. coli</i> strains. A detailed analysis of their genomic and biological properties, including host range and stability under various temperature and pH conditions was conducted. Transmission electron microscopy provided further insights into phage morphology. These findings demonstrate the potential of phage therapy as an alternative treatment for antibiotic-resistant infections, especially in CF patients. As multidrug-resistant bacteria become increasingly prevalent, the discovery of novel bacteriophages offers a promising solution to combat these difficult-to-treat infections. Further research is required to explore their clinical applications.