Liposomal Mycobacteriophage D29: Therapeutic Efficacy Against a Drug-Resistant Strain of <i>Mycobacterium tuberculosis</i> in an Experimental Study on Inbred Mice and Associated Toxicity Evaluation

Background: The use of liposomal lytic mycobacteriophage D29 has been shown to be an effective and less toxic alternative to traditional antibiotics for treating tuberculosis caused by drug-resistant M. tuberculosis strains. Methods: A previously developed liposomal formulation of mycobacteriophage D29, with a size of 0.45 micrometers, was used. The efficacy of this preparation of lytic mycobacteriophages was studied in a model of tuberculosis infection in C57BL/6 mice caused by the multidrug-resistant M. tuberculosis CAO120/26 (SHRE) strain. The acute and chronic toxicity of this liposomal formulation was also investigated. Results: The results demonstrated a significant antimycobacterial effect of a liposomal mycobacteriophage D29-based drug against tuberculosis infection caused by the drug-resistant pathogen. The number of CFUs of MTB in lung homogenates from untreated infected mice was 326875 ± 149221, whereas in treated mice, it was 307 ± 163. In the study of the acute and chronic toxicity of the drug, no significant signs of toxicity were found. Conclusions: The results of experimental studies on the use of liposomal formulations of lytic mycobacteriophages in animal models suggest that they may have potential to significantly enhance the efficacy of chemotherapy in patients with tuberculosis, including those with drug-resistant strains.