Morphometric and Densitometric Indicators of Salmonella Biofilm under the Exposure of a Disinfecting Preparation

Abstract

Objective: Study of morphometric and densitometric parameters of biofilms of microorganisms under the influence of a disinfectant.

Materials and methods: To study the morphology of biofilms in vitro, bacteria were cultivated at 37 ° C for 24 hours. When preparing preparations for optical microscopy, fixation was performed with a mixture of alcohol: ether – 1 : 1 for 10 minutes, stained with 0,5 % gentian violet solution - 2 minutes. The optical density of biofilms was determined by the degree of binding of crystal violet, the optical density was determined in an Immunochem–2100 microplate photometric analyzer (HTI, USA) at a wavelength of 490 nm. To obtain representative information, optical microscopy was performed by random selection of the field of view of a microscope model "BIOMED MS-1 Stereo" (Russia).

Results: When studying morphometric parameters after 48 hours of cultivation, 37 ° C with optical microscopy of preparations stained with gentian violet, general patterns of the formation of the heterogeneous structure of S. enteritidis biofilms were revealed: adhesion; fixation; maturation; growth; dispersion. Based on the analysis of densitometric indicators of microorganism cultures, it was established that after 48 hours of cultivation, the values ​​of the absolute values ​​of the optical density of microorganisms: OD_s – 0,395±0,11, the intensity of biofilm formation – I ≥ 0,2–0,3, S. enteritidis microorganisms are moderate producers biofilms. Indicators of optical density of S. enteritidis under the influence of the drug "Ecodes", 0,10 %: OD_s – 0,383±0,10 intensity of biofilm formation – I ≥ 0,2–0,3, cultures of microorganisms S. enteritidis – moderate producers of biofilms. Accordingly, when exposed to concentrations of 0,15 and 0,25 %: OD_s – 0,281±0,09 – 0,204±0,09, the intensity of biofilm formation – I ≥ 0,1–0,2, microorganisms S. enteritidis are weak producers of biofilms.

Conclusion: During the formation of S. enteritidis biofilms, general patterns of the formation of the heterogeneous structure of S. enteritidis biofilms were revealed: adhesion; fixation; maturation; growth; dispersion. The frequency of occurrence of clusters - aggregation of microorganisms, united by a layer of the extracellular matrix, significantly decreased under the influence of various concentrations of the disinfectant "Ecodes".