Abstract
The article presents the results of the first study on the influence of biologically active substances Lactobacillus rhamnosus GG ATCC 53103 and Saccharomyces boulardii, obtained according to the author`s method, on growth of gram-negative bacteria with broad medical resistance: Pseudomonas aeruginosa PR, Klebsiella pneumoniae PR, Lelliottia amnigena (Enterobacter amnigenus) PR using the spectrophotometric method. Disintegrates of L. rhamnosus GG and S. boulardii were obtained using low-frequency ultrasound processing of suspension of probiotic strains, and metabolites – through cultivation of lactobacteria and saccharomycetes in disintegrates of probiotic microorganisms. To samples of test-cultures with studied filtrates of disintegrates or metabolites we added growth medium and cultivated them (period of monitoring was 5- and 24-hours). Results of the studies were expressed as the percentage of inhibition of increment in polyresistant gram-negative bacteria under the impact of biologically active substances of probiotic microorganisms. Five-hour incubation of test-strains with the studied samples of lactobacteria led to inhibition of their growth properties by 85.6–96.7%. Growth of bacteria under the impact of substances of saccharomycetes was inhibted by 45.1–92.5%. Twenty-four hour exposure of the test-cultures in filtrates of L. rhamnosus GG and S. boulardii caused 100% inhibition of P. aeruginosa and L. amnigena polyresistant strains. Temporal interval of cultivation directly proportionally affected the extent of inhibition of growth of microorganisms: we determined direct correlation dependence within 0.789–0.991. Maximum inhibition of increment of the studied pathogens was observed under the influence of metabolites of lactobacteria, obtained by cultivating primary producers in their disintegrate. We determined a high level of anti-microbial activity of metabolites from L. rhamnosus GG and S. boulardii obtained by cultivation of probiotics in disintegrates against bacteria resistant to a broad range of preparations, which allows us to consider these substances as promising for development of anti-microbial preparations of a new generation against etiologically significant antibiotic-resistant gram-negative microorganisms.
Highlights
Among the great variety of infectious diseases, diseases of the respiratory system remain highly relevant (Dorofeev et al, 2017; Jakovlev, 2017; Ponomarev, 2017)
Obtaining of metabolites from bacteria and fungi in disintegrates of probiotic cultures: 1) metabolites from Lactobacillus were obtained by cultivation of suspensions of L. rhamnosus GG with optical density of 10.0 units according to McF scale in their disintegrates (Isajenko et al, 2017); 2) metabolites from Saccharomyces were isolated in a similar way, by growing suspensions of S. boulardii in their disintegrates of fungi; 3) metabolites from Saccharomyces, differed from the previous by cultivating suspensions of fungi in disintegrate of bacteria (L.°rhamnosus); 4) combination of metabolites from Lactobacillus and Saccharomyces were obtained by combined growing of microbial cells of L
The conducted studies revealed that under the impact of the studied probiotic products from L. rhamnosus GG and S. boulardii, growth of P. aeruginosa PR test culture was statistically reliably inhibited, which manifested in reduction of optical density (Fig. 1)
Summary
Among the great variety of infectious diseases, diseases of the respiratory system remain highly relevant (Dorofeev et al, 2017; Jakovlev, 2017; Ponomarev, 2017). Dangerous are acute respiratory diseases caused by multi drug-resistant pathogens (Wald, 2011). Difficulty in treating such infectious diseases occurs due to non-effective antibacterial therapy, and the ability of polyresistant pathogens to transmit resistance to other microorganism (Arcilla, 2017, Tsutsui et al, 2018). This fact was found in Escherichia сoli, Pseudomonas aeruginosa, Burkholderia cenocepacia (El-Halfawy et al, 2013). Scientists presume that in 20 years practical medicine will lose its last efficient anti-bacterial preparations (Kraker et al, 2016)
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