[The capacity of Escherichia coli to form biofilms in presence of nano-particles of aluminum oxide.]

The effect of various concentrations of suspensions of nanoparticles of aluminum oxide of size of 30 and 70 nm on capacity of Escherichia сoli to form biofilm in vitro was examined. The study used highly virulent strain of Escherichia сoli isolated from a patient with chronic pyelonephritis. The strain was characterized by high capacity of forming biofilm. It is established that nanoparticles of aluminum oxide with size of 30 nm inhibited capacity of forming biofilm. At that, a reliable decreasing of analyzed indication in two times occurred and analyzed clones of Escherichia сoli passed to category of microorganisms with average capacity of forming biofilm. It is established that intensity of factor suppression depended both on size and concentration of nanoparticles in medium. The most effective in suppression of capacity of forming biofilm was concentration of nanoparticles of aluminum oxide 0,015 mkg/ml that decreased intensity of factor in two times.

[Modification of antibiotic resistance in microbial symbiosis].

In antibiotic therapy it is necessary to use drugs active against the pathogen in its association with the host normal microflora. The aim of the study was to investigate modification of antibiotic resistance under conditions of the pathogen association with the representatives of the host normal microflora and to develop the microbiological criteria for determining effectiveness of antibacterials. Modification of microbial antibiotic resistance was investigated in 408 associations. Various changes in the antibiotic resistance of the strains were revealed: synergism, antagonism and indifference. On the basis of the results it was concluded that in the choice of the antibiotic active against Staphylococcus aureus and Streptococcus pyogenes the preference should be given to oxacillin, gentamicin and levomycetin, since the resistance of the pathogens to these antibiotics under the association conditions did not increase, which could contribute to their destruction, whereas the resistance of the normoflora increased or did not change, which was important for its retention in the biocenosis. The data on changeability of the antibiotic resistance of the microbial strains under the association conditions made it possible to develop microbiological criteria for determining effectiveness of antibiotics in the treatment of inflammatory diseases of microbial etiology (RF Patent No. 2231554).