Express method for determining the sensitivity of pathogens of bacterial complications in COVID-19 to bacteriophages

BACKGROUND: In recent years, there has been a catastrophic increase in the resistance of bacterial strains to antibacterial drugs. The spread of the novel coronavirus disease (COVID-19) pandemic has led to the overuse of antibiotics, which has led to an even greater spread of resistant strains in hospitals. Given the accumulated positive experience in using bacteriophages, it is advisable to use them in patients after determining the sensitivity of each strain of isolated bacteria to bacteriophages. Since Klebsiella pneumoniae was the most frequently isolated bacteria in complicated forms of COVID-19, it became necessary to determine the sensitivity of these and other gram-negative bacteria to the corresponding bacteriophages. AIM: This study aims to reduce the time for determining the sensitivity of an isolated microorganism culture to bacteriophages by developing an express method. MATERIALS AND METHODS: The study used 30 strains of pan-resistant Gram-negative microorganisms from the collection of the Museum of the Laboratory of Medical Bacteriology of the Pasteur Research Institute of Epidemiology and Microbiology in St. Petersburg: Klebsiella pneumoniae (n=10), Escherichia coli (n=10), Pseudomonas aeruginosa (n=10), and also preparations of bacteriophages manufactured by JSC NPO Microgen: Bacteriophage Klebsiella polyvalent purified; Bacteriophage coliproteus; Pseudomonas aeruginosa bacteriophage. RESULTS: Of the strains studied, 4 out of 10 studied K. pneumoniae strains, 6 out of 10 E. coli strains, and 7 out of 10 P. aeruginosa strains were susceptible to polyvalent bacteriophage preparations. Reliable results were obtained 3 hours after the sensitivity of isolated cultures to bacteriophages was established, which is undoubtedly the most important finding of the study. CONCLUSION: The developed method for determining the sensitivity of gram-negative bacteria to bacteriophages enables reducing the study time by 6 times (up to 3 hours), which affects the timing of etiotropic therapy selection with bacteriophages for each patient.