Anti-phage entibody response in phage therapy against healthcare-associated infections (HAIs)
The objective. To evaluate anti-phage аntibody response in phage therapy against HAIs. Patients and methods. Forty-two patients on prolonged mechanical ventilation in a neurological ICU were administered bacteriophage cocktail per os, including six patients repeatedly - from 3 to 5 courses. Anti-phage immunity was evaluated by ELISA before and after the treatment. Results. Initially, from 87.5% of the patients' samples A. baumannii, K. pneumoniae, P. aeruginosa were isolated. In the first courses of phage therapy, effective sanitation was proved in 54-62.5% of cases. Pharmacokinetic research assumed a systemic action of enteral forms of bacteriophages. Repeated courses of phage therapy with the same strains did not lead to a substantial eradication of pathogens. Anti-phage immunity after a single application of bacteriophage cocktail with a certain composition of strains was detected with ELISA by the presence of titer of specific IgG antibodies in the range of 1/16-1/4096 (no antibodies were present in patients who did not take the cocktail). Conclusion. The effectiveness of a bacteriophage may be reduced if a patient is given a repeated treatment due to the formation of anti-phage antibodies. In order to retain performance of phage therapy, a change in the composition of strains in the phage cocktail is necessary.