Abstract
1) In 5 out of 81 samples of dental apical foci (61.7%), 5 strains of tetragena were isolated. All the strains produced yellow pigmente in the medium. 4 strains out of five were isolated by picking up from among contaminants such as staphylococci and streptococci, but the remaining one strain was obtained from its single colonies. 2) Although organisms of this genus have been referred to as being negative in gelatin liquefaction, one strain of the present isolates proved positive in this reaction. 3) Milk coagulation was shown by 2 out of 5 strains. 4) Indol reaction was nagative in all the strains studied. 5) Plasma coagulation was shown by 4 out of 5 strains studied. 6) Mannit fermentation was negative in all the strains. 7) No colony of this organism was grown by 72 hours culture on the mannit-salt agar. 8) Neither human nor rabbit blood was coagulated by this organism. 9) In bouillon, light to heavy turbidity and precipitation occurred with all the strains of the organism. 10) 4 out of 5 strains of this organism were risistant to penicillin. 11) 2 out of 5 strains were resistaht to streptomycin. 12) 3 out of five strains were resistant to chloromyceetin. 13) All the strains were resistant to kanamycin. 14) There were one strain which was double-resistant to penicillin and kanamycin and another one strain which was double-resistant to chloromycetin and kanamycin. There was each one straine which was triple-resistant to either penicillin, streptomycin and kanamycin or to penicillin, chloromycetin and kanamycin. Finally there was one quadruple-resistant resistant organism to penicillin, streptomycin, chloromycetin and kanamycin. 15) The quadruple-resistant organism was most active in developing plasma coagulation.
