Australian scientists have studied* the in vivo efficacy and safety of bacteriophage cocktails in the treatment of sinusitis caused by Pseudomonas aeruginosa .

P. aeruginosa is a pathogenic bacterium that is often resistant to antimicrobials. This complicates the treatment of chronic infections caused by this pathogen, including sinusitis and rhinosinusitis.

To study the antimicrobial activity and safety of phage therapy for pseudomonas rhinosinusitis, sheep with P. aeruginosa infection in the frontal sinuses were used as a model. The phage cocktail contained lytic phages specific for P. aeruginosa .

To evaluate the effectiveness of phage therapy, after 7 days of biofilm formation on the mucosa, animals were rinsed through trephination holes twice daily with a phage cocktail at a concentration ^{of 10-10} BUO/ml (experimental group) or with saline (control group). Biofilm status was assessed using optical microscopy and the LIVE/DEAD BacLight system.

To assess the safety of the phage cocktail, animals were rinsed through trephination holes with the phage cocktail (experimental group) or solvent (control group) for three weeks.

During treatment, blood and fecal samples were collected from the animals. Histopathological examinations of tissues from the frontal sinuses, lungs, heart, spleen, and kidneys were also performed. The condition of the ciliated epithelium of the sinuses was examined using scanning electron microscopy.

A study of biofilms treated with bacteriophages revealed a significant reduction in their mass. Bacteriophages persisted on the mucosa for less than 16 hours after the final sinus rinse with the phage preparation.

No tissue damage was observed as a result of phage therapy, and no side effects were reported with the phage cocktails. Phages were excreted in significant quantities in feces and were sporadically detected in blood and organ samples.

* Fonga SA, Drillinga AJ, Ooia ML et al. Safety and efficacy of a bacteriophage cocktail in an in vivo model of Pseudomonas aeruginosa sinusitis // Translational Research, Available online 19 December 2018 https://doi.org/10.1016/j.trsl.2018.12.002