The biofilm formation of freshly isolated and vaccine strains of Bordetella pertussis of different serotypes

Abstract

Aim. To study the formation of biofilms by freshly isolated and vaccine strains of Bordetella pertussis of different serotypes.Materials and methods. The intensity of biofilm formation by B. pertussis strains in 96-well round-bottom polystyrene plates by using three sowing doses of microbial cells (1,25 IOU/ml, 2,5 IOU/ml and 5,0 IOU/ml) was estimated by staining with 0,1% gentian-violet solution. The results were interpreted after measuring the optical density (OP) of the colored solvent at a wavelength of 600 nm.Results. The highest intensity of biofilm formation was found in the newly isolated strain No. 211 and vaccine strain No. 475, both belonging to serotype 1.2.3. Cultures of these strains formed dense biofilms at all sowing doses of microbial cells. Certain differences in the intensity of biofilm formation were found between freshly isolated and vaccine strains of serotypes 1.2.0 and 1.0.3, especially when using a sowing dose of 5,0 IOU/ml. Freshly isolated strains at this dose formed dense biofilms, while two of the three vaccine strains formed moderate biofilms, and one strain was dense.Conclusion. The revealed differences between the strains of B. pertussis in the intensity of biofilm formation may be associated with the peculiarities of the expression of agglutinogens, as well as other surface structures of microbial cells involved in the adhesion process on the substrate.