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The effect of Antibacterial Drugs on the Formation Salmonella Biofilms
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| Author:
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EKATERINA LENCHENKO, VAN KHAI, YURY VATNIKOV
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| Abstract:
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The aim of the work was to study the morphological and densitometric parameters of Salmonella biofilms when exposed to various concentrations of the antibacterial drug "Ceftriaxone".
Materials and methods. To study the morphology of biofilms in vitro, bacteria were cultivated at 37 ° C for 24 h. When preparing preparations for optical microscopy, fixation was performed with a mixture of alcohol: ether - 1: 1 for 10 minutes, stained with a 0.5% solution of gentian violet - 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 carried out by random selection of the field of view of a microscope model "H604T Trinocular Unico" (H604T, USA).
Research results. When studying the sensitivity of bacteria by diffusion in agar, it was found that the diameter of the zone of inhibition of the growth of microorganisms under the influence of different concentrations of ceftriaxone was 10.20 ± 0.4-17.15 ± 0.2 mm.
Analyzing the indicators of optical density (Optical Density, OD), it was established that microorganisms S. enteritidis experiment (I): were strong producers of biofilms, the optical density of the sample ODs - 0.457 ± 0.13 (Optical Density of the sample - ODs) exceeded the optical density of the control ODc - 0.099 ± 0.03 (Optical Density of the control - ODc) more than 4 times.
Optical density indices under the influence of the drug "Ceftriaxone", 25.0 µl - experiment (II): ODs - 0.371 ± 0.09 exceeded the control values ODc - 0.099 ± 0.08 less than 4 times. At a concentration of 50, µl: ODs - 0.35 ± 0.01 exceeded the control values ODc - 0.096 ± 0.02 less than 4 times. Accordingly, when exposed to concentrations of 25.0 and 50.0, microorganisms are moderate producers of biofilms. When exposed to a concentration of 100.0 µl: ODs - 0.194 ± 0.05, the control indicators ODc - 0.098 ± 0.09 were less than 2 times higher, that is, microorganisms are weak biofilm producers.
Conclusion. During the formation of biofilms of bacteria S. enteritidis, the following stages were observed: adhesion; fixation; the formation of a monolayer, intercellular connections - coaggregation, growth of microcolonies; cluster formation and biofilm architectonics; 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 antibacterial drug "Ceftriaxone".
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| Keyword:
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salmonella, biofilms, optical density, optical microscopy, electron microscopy, antibiotic resistance
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| EOI:
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| DOI:
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https://doi.org/10.31838/ijpr/2021.13.01.392
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| Download:
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