APPLICATION OF BACTERIOPHAGES AGAINST MULTIDRUG-RESISTANT STRAINS OF KLEBSIELLA PNEUMONIAE

Background. The emergence of antimicrobial-resistant microorganisms poses a serious global public health challenge. Klebsiella pneumoniae is among the most common pathogens responsible for healthcare-associated infections, particularly in critically ill patients. The prevalence of multidrug-resistant (MDR) K. pneumoniae has increased dramatically worldwide over recent decades, presenting an urgent threat to public health. In the absence of effective treatments for severe bacterial infections caused by antibiotic-resistant strains, bacteriophages represent a targeted and promising adjunct – and in some cases, an alternative – to conventional therapy. Aim: to explore the possibility of isolating bacteriophages against PDR (pan-drug resistant)/XDR (extensively drug-resistant) strains of K. pneumoniae using urban wastewater samples, and to investigate the spectrum of their activity under in vitro conditions. Materials and Methods. Bacteriophages were isolated using the enrichment method, and their specificity was evaluated using a modified Gratia method and the spot test. Morphological characterization of the isolated phages was performed via electron microscopy. Antimicrobial susceptibility testing was conducted using disk diffusion and broth microdilution methods. Detection of antibiotic resistance genes (blaNDM-1, blaKPC, blaCTX-M-1, and gyrA) was performed by PCR. Results. A total of 212 bacteriophages were isolated from municipal wastewater samples, demonstrating lytic activity against a broad spectrum of clinical isolates and reference strains of K. pneumoniae, including antibiotic-resistant variants. Specifically, 56.1% of the phage isolates showed specific activity against a pre-characterized panel of 15 PDR/XDR K. pneumoniae strains. Notably, each clinical isolate with acquired extensive drug resistance was susceptible to multiple phages, and 14 phages lysed more than 50% of the tested bacterial cultures. The phages exhibited both narrow and broad host ranges, supporting the formulation of effective phage cocktails for potential therapeutic use. Conclusions. The findings demonstrate the high potential of bacteriophages as an alternative or adjunctive strategy in combating multidrug-resistant K. pneumoniae. These experimental results highlight the importance of further development of phage therapy approaches, especially in the context of escalating multidrug-resistant infections.