Isolation and purification of bacteriocin from Prevotella intermedia (Bacteroides intermedius)

Thirty-three out of 46 strains of Prevotella intermedia (Bacteroides intermedius) isolated from gingival deposits of patients with adult periodontitis possessed the ability to inhibit growth of P. intermedia strain ATCC 25611, and 6 of the 33 showed strong inhibitory activity. Thirteen isolates did not have the ability to inhibit the growth of P. intermedia strain ATCC 25611. An inhibition factor from one of the isolates, P. intermedia TH14 which had strong inhibition, was purified and characterized. Bacteriocin TH14 activity was effective against only P. intermedia ATCC 25611 and Fusobacterium nucleatum, but not against other crevicular bacteria, including P. intermedia ATCC 33563, Porphyromonas gingivalis (Bacteroides gingivalis), Capnocytophaga sputigena and Actinobacillus actinomycetemcomitans. Streptococci, actinomyces, and veillonellas were not inhibited by bacteriocin TH14. Bacteriocin TH14 was heat sensitive, proteinaceous with molecular weight of 1,700 daltons and inhibited the growth of strain ATCC 25611 in 15 minutes. The growth inhibition of P. intermedia ATCC 25611 by bacteriocin TH14 was found to be due to the bactericidal activity of the bacteriocin.