[Biofilm formation by group A Streptococci of various types and study of antibiotics effect on this process]

Evaluation of the ability to form biofilms by various M, T and MT-types of group A streptococci (GAS), as well as study of the effect of various antibiotics on biofilm formation.

43 strains of various M and T type GAS were studied. The cultures were grown in Todd-Hewitt broth with the addition of 0.5% yeast extract. Comparative evaluation of the ability to form biofilm was carried out using photometry. Benzylpenicillin, oxacillin, cepha- losporin, cefuroxime and ceftriaxone antibiotics were used at various concentrations.

GAS differ significantly by their ability to form biofilms. The highest ability was noted in 8 strains--2M, 9M, 12M, 13M, 19M, 30M, 36M-types and 6MT type. Simultaneous introduction of GAS cultures and antibiotics into the culture well, except for ceftriaxone, resulted in growth inhibition of both plankton cells and biofilms.

The ability of GAS to form biofilm depends on streptococci serotype. During simultaneous introduction of GAS with antibiotics into the well, the biofilm does not form.