Phagebiotics in treatment and prophylaxis of healthcare-associated infections.

We have developed a phagebiotic composition using 8 virulent bacteriophages (2 strains of each species) which are able to lyse Acinetobacter baumannii, Klebsiella pneumoniae, Pseudomonas aeruginosa and Staphylococcus aureus. The unique character of the developed composition is ensured by particular properties of each bacteriophage comprising the preparation, including their range of lytic activity toward specific bacterial pathogens, morphology of their plaques, cycle of their development, restriction profile of their DNAs, specificity of their genomes (based on complete genome sequencing), and other properties. The preparation did not produce any signs of acute or chronic intoxication in the experimental animals. Therapeutic and prophylactic efficiency of the phagebiotic composition was demonstrated in the prevention and treatment of the experimental acute K. pneumoniae infection in mice. The investigations have shown that the preparation possesses a high therapeutic efficiency and is highly competitive with ciprofloxacin which is very effective against the infective strain K. pneumoniae. Our small-scale clinical trial was aimed to evaluate therapeutic effectiveness of the phagebiotic composition in an epidemiological emergency situation in an intensive care unit, caused by multi-resistant strains of Acinetobacter baumannii, Klebsiella pneumoniae and Pseudomonas aeruginosa. Seventy nine per cent of the initial samples from 14 patients' endotracheal aspirate, blood and urine were contaminated. Twenty-four hours after the 3-day phage therapy (20 ml of cocktail at a titer for each phage 108 pfu/ml were introduced intragastrically through a tube once a day) contamination level dropped to 21%. Hence the obtained results enabled us to create a new phagebiotic composition that may be used as an alternative to antibiotics to treat these healthcare-associated infections.

[Efficacy of enterocin S760 in treatment of mice with anthrax infection due to Bacillus anthracis M-71].

The therapeutic efficacy of enterocin S760, a broad spectrum antimicrobial peptide produced by Enterococcus faecium LWP760 was tested on mice infected with Bacillus anthracis M-71 to induce anthrax (second Tsenkovsky's vaccine). Intraperitoneal four-, two- or one-fold administration of the peptide in a dose of 25 mg/kg for 10 days for prophylactic (1 hour after the contamination) and therapeutic (24 hours after the contamination) purposes prevented or cured the infection in 90-100% of the mice versus the 100-percent lethality in the control (untreated animals). The antimicrobial activity of enterocin S760 against B. anthracis M-71 in vivo correlated with activity in vitro. Enterocin S760 is considered a novel promising antimicrobial for the treatment of grampositive and gramnegative infections.

[Use of enterocin S760 for prevention and treatment of experimental Salmonella infection in mice].

AIM: To demonstrate treatment efficacy of bacteriocin S760 synthesized by Enterococcus faecium 760 for septic Salmonella infection in mice. MATERIALS AND METHODS: One hundred mice, which were intraperitoneally inoculated with 100 LD50 of Salmonella enteritidis strain 92 Rif(r), received bacteriocin 1 hour (prevention) or 48 hours (treatment) after inoculation in doses 25, 50, or 100 mg/kg every 6 hours during 5 or 10 days. RESULTS: Use of peptide S760 for prophylaxis in dose 50 mg/kg during 10 days prevented lethal infection in 100% of animals, whereas its use for treatment cured 70% of animals with generalized salmonellosis. Shortening of treatment course from 10 to 5 days and reducing dose of bacteriocin led to less pronounced treatment effect but in all animals it was expressed by increase of mean length of life compared to control (not treated). CONCLUSION: Obtained results demonstrated high treatment efficacy of bacteriocin S760 during septic salmonellosis and perspectives of its use in medicine and animal health.