Isolation and Characterization of a Klebsiella pneumoniae Specific Lytic Bacteriophage from a Hospital Waste-water Treatment Plant

Introduction: Phage therapy has gained interest as a potential alternative for treatment of infections caused by multidrug-resistant (MDR) pathogens. This study aimed to isolate a lytic bacteriophage with the potential to lyse clinical isolates of Klebsiella pneumoniae. Methods: Water samples were collected from a hospital waste-water treatment plant in Tehran. The samples were filtered and mixed with an overnight grown culture of K. pneumoniae. (ATCC ۱۰۰۳۱) followed by incubation at ۳۷°C overnight. Phage titration, latent period, and burst size measurements were carried out by the double-layer agar method using the K. pneumoniae ATCC strain. The isolated phage w:as char:acterized by transmission electron microscopy (TEM), thermal, pH, and chloroform stability. Susceptibility of Escherichia coli, Acinetobacter baumannii, Pseudomonas aeruginosa, ESBL producing K. pneumoniae and ۵۱ MDR K. pneumoniae isolates was measured by placing ۲۰ µl of the phage suspension (۱۰۸ PFU) onto bacterial lawns followed by incubation at ۳۷°C overnight. Formation of clear zones indicated susceptibility. Results: The isolated lytic bacteriophage formed small clear plaques with a latent period of ۴۰ min and a burst time of ۵۲ min, corresponding to ۳۵-۴۰ phage particles per infected cell. TEM results showed that the phage resembled the tailed Siphoviridae family and was designated vB_KpnS-Teh.۱. The phage vB_KpnS-Teh.۱ was most stable at ۳۷°C, pH ۷ and was resistant to chloroform. Conclusion: The isolated lytic phage showed specificity towards K. pneumoniae. Further research will determine its potential in the treatment of K. pneumoniae infections.