NEW FINDINGS ON THE MICROBIAL-FLORA ASSOCIATED WITH ADULT PERIODONTITIS

The predominant microbial flora associated with adult periodontitis wa s investigated in 21 patients aged 20-40 years. Microorganisms from sa mples of subgingival plaque were cultured on selective and non-selecti ve media under aerobic and anaerobic conditions. Ten species or groups out of a total of 31 were found to comprise the predominant cultivabl e flora: diphtheroids, Porphyromonas asaccharolytica, coagulase-negati ve staphylococci. ' Streptococcus milleri'-group, Bacteroides ureolyti cus. Capnocytophaga ochracea. the Prevotella veroralis/buccalis comple x, P. intermedia. P. oralis and unidentified Prevotella spp. Two speci es previously reported at periodontitis sites, namely P. gingivalis an d Fusobacterium nucleatum, were not isolated, whereas Prevotella speci es accounted for the majority of isolates in this investigation. The l arge proportions of non-pigmented Prevotella species, P. asaccharolyti ca and B. ureolyticus that were found have not generally been reported previously. The role of these microorganisms and also coagulase-negat ive staphylococci, diphtheroids and the 'Streptococcus milleri'-group requires further investigation in adult periodontitis.