Estudo in vitro das interações bacterianas de bactérias isoladas de infecções endodônticas e caracterização parcial de substância(s) antagonista(s) produzida(s) por amostra de c.butyricum

Abstract

The oral microbiota is composed by about 500 bacteria species, but, in a given endodontics infection, only about 1 to 12 species are recovered. Factors such as bacterial interactions, by the action of antagonist substances and bacteriocins, can influence bacterial growth in this site. In this study, bacterial interactions that occur among microorganisms recently recovered from human endodontics infections are evaluated in vitro. With this objective, the diffusion technique in agar by the use of different culture media (agar BHI-S, MRS e AC) was used. The antagonist substance produced by Clostridium butyricum was also partially characterized. The bacterial species selected were: Bifidobacterium adolescentis, Gemella morbillorum, Clostridium butyricum, Fusobacterium nucleatum, Peptostreptococcus. micros, Lactobacillus acidophilus, Prevotela intermedia/nigrescens. Synergism wasnt observed among the selected species, while Antagonism was detected among the following interactions: G.morbillorum and L. acidophilus, P. intermedia/nigrescens; B. adolescentis and G.morbillorum, C. butyricum, F. nucleatum, P. intermedia/nigrescens, P. micros; C. butyricum and B. adolescentis, G. morbillorum, F. nucleatum, P. intermedia/nigrescens; F. nucleatum and B. adolescentis, C. butyricum, P. micros; P. micros and B. adolescentis, C. butyricum, P. intermedia/nigrescens, L. acidophillus; L. acidophillus and B. adolescentis, F. nucleatum; P. intermedia/nigrescens and all the producing species. The presence of bacteriophages in the inhibition zones wasnt detected. It can be observed that the type of culture media used interfered in the results: the AC media, when concentrated, showed better results than the BHI-S. Finally, the results referring to partial characterization of the substance produced by C. butyricum showed that it is stable in pH ranging from 3.5 to 6.5 and in temperatures of 60º, 70º and 100ºC; being insensitive to the action of proteolitics enzymes: trypsin, alpha-chymotripsin and papain, therefore demonstrating that it is a thermo-resistant antagonist substance and apparently of non-proteic nature. The results confirm data from literature, which indicate that factors such as pH, cultive media and temperature interfere in the expression of antagonist substance activity, therefore being important ecological determinants in the selection of bacteria on the inside of the Root Canal Systems.