Features of formation of Yersinia enterocolitica biofilms

Abstract

Aim: The work aimed to study the morphology of colonies and their comparison by features of the formation of Yersinia enterocolitica biofilms. Materials and Methods: Bacteria were cultured on a Yersinia Selective Agar medium ("CIN-agar") at 28°C for 24 h. The microorganisms were grown in meat-peptone broth with 1.0% glucose to measure the absolute values of the optical density of the culture. The optical density of the liquid was determined in a microplate photometric analyzer Immunochem-2100 (HTI, USA) at a wavelength of 490 nm. For the study of biofilms, the specimens were fixed for 3-5 h in pairs of 25.0% solution of glutaraldehyde (according to DV), and pairs of a 1.0% aqueous solution of osmic acid (OSO4) were used for contrasting for 2-3 min. The specimens were examined with stereoscopic microscopy "BIOMED MS-1 Stereo" (Russia) and scanning electron microscope "TM 3030 plus" (Holland). Results: With stereoscopic microscopy of the colonies of Y. enterocolitica, the S-forms had an elevated intensely colored center, radial striation along the periphery, smooth edges, d ≤ 1.0 mm. R-form colonies had a dark color and a dry surface, were tuberous and had a dense center with a peripheral ridge, rugged edges, d ≥ 1.5 mm. The optical density of the Y. enterocolitica S-form showed that this type of microorganism belongs to the moderate producers of biofilms since the optical density of the sample (density of the sample - Ds) exceeded the optical density of control (density of the control - Dc) by 3 times. In Y. enterocolitica R-form (D ≤ 0.197) weakly produced biofilms, the optical density of the sample exceeded the optical density of the control by