RESEARCH, EXTRACTION AND PARTIAL CHARACTERIZATION OF BACTERIOCIN-TYPE ANTAGONIST SUBSTANCE PRODUCED BY Fusobacterium necrophorum (Atena Editora)

Abstract

Fusobacterium necrophorum is a Gram-negative anaerobic bacillus, from the amphibiotic microbiota of animals, including humans, and is associated with diseases, in different places, such as Lemierre Syndrome. Considering the clinical relevance of this microorganism, the in vitro production of an antagonist substance by F. necrophorum ATCC 25286 against 14 reference samples that integrate the human oral microbiota was evaluated. The species that exhibited greater sensitivity to the antagonist substance were Peptostreptococcus anaerobius, Porphyromonas gingivalis, F. nucleatum Streptococcus mutans and Prevotella intermedia, the phenomenon being best evidenced in Brain Heart Infusion Agar supplemented with yeast extract and glucose at pHs 6.0 and 7.0. It was shown that the antagonistic ability was not related to the production of acids, bacteriophages, hydrogen peroxide or residual chloroform. The protein fractions precipitated by ammonium sulfate that showed activity were extra and intracellular, precipitated at 50 and 80%. It was observed that C50 and C80 maintained their activity at pH values 7.0 to 9.0 and 5.0 to 9.0, respectively. Regarding heat treatment, C50 was more unstable than C80. After treatment with proteases, the active extracts lost activity, confirming the protein nature of the substance. The molecular mass of the substance was estimated between 37 and 50 kDa, according to the “in situ” activity against P. anaerobius. This is the first report of antagonistic activity of F. necrophorum and the heteroantagonism relationship observed evidences a possible ecological role of the substance in the oral ecosystem, possibly favoring indigenous bacteria with pathogenic potential, such as F. necrophorum, which is why this phenomenon is considered related to virulence.