UDC 636.5.087.69
doi: 10.36871/vet.san.hyg.ecol.202104010
Authors
Ekaterina M. Lenchenko
Damir I. Udavliev
Moscow state University of food productions, Moscow, Russia
Inna B. Pavlova
All-Russian Research Institute for Veterinary Sanitation, Hygiene and Ecology –
Branch of Federal Scientific Center – K.I. Skryabin, Ya.R. Kovalenko
All-Russian Research Institute of Experimental Veterinary
Medicine, Russian Academy of Sciences, Moscow, Russia
Abstract
The results of morphometric and densitometric parameters biofilms are presented, effective methods of detecting uncultivated viable microorganisms isolated from a representative sample of objects of veterinary and sanitary supervision are tested and selected. Optical, luminescent and scanning electron microscopy revealed the formation of a three-dimensional structure biofilms in the form a dense network consisting of gram-negative and gram-positive bacteria, yeast cells, hyphal and pseudohyphalic forms, surrounded by an intercellular polymer matrix. The presence hyphae of microscopic fungi causes an increase in the number of cells adhered to the substrate, microcolonies were formed from bacteria and yeast cells of microscopic fungi. The pathogenesis of the syndrome of overgrowth of microorganisms is provided by the presence of various dissociative variants, the dispersion of uncultivated bacterial cells, which gain advantages in the hyperagregation of the architectonics of heterogeneous biofilms. Multilayer membranes, vesicles, cells with a defective cell wall, spheroplasts, protoplasts, L-shapes, needle-like and giant structures, and revertant cells were identified. The dynamics of changes in the viable structures microorganisms was characterized by alternating periods of decrease and increase in the intensity of biofilm formation. When detecting the viability of microorganisms in the composition biofilms, viable and non-viable cells were differentiated – a green luminescence spectrum and a red luminescence spectrum, respectively. The dissociation of the population caused an increase in the concentration of R-dissociant cells with a higher growth rate, cell lysis was detected after 48–72 h of cultivation, a change in the ratio phenotypic forms was observed – the M-dissociant was predominant. The study of the heterogeneous structure of the population, without disturbing the natural architectonics of biofilms, revealed direct correlations (r = 0,89) between morphometric (≥90 % of the field of view) and densitometric parameters (OD). The efficiency of a nutrient medium containing pancreatic hydrolyzate, mannitol, L-asparagine and glycerol was established for the repair of the cell wall, the reversal of L-forms of microorganisms.
Keywords
adhesion, biofilms, bacteria, dispersion, densitometry, microscopic fungi, extracellular matrix, luminescence, uncultivated bacteria, scanning microscopy
