Isolation and Taxonomy of Filamentous Fungi in Endodontic Infections

Introduction: The purpose of this study was to research the presence of filamentous fungi in the root canals of teeth with pulp necrosis and periapical lesions and to perform the taxonomic study of the isolates. Methods: Samples collected from 60 root canals with sterile absorbent paper points were inoculated in Sabouraud dextrose agar supplemented with chloramphenicol. The material was cultured from 7-14 days at room temperature to observe mycelial growth. Samples with growth were seeded in media specific for microculture (CYA agar, malt extract agar, or potato dextrose agar). Taxonomy was evaluated by macroscopic examination and optical microscopy. Results: Filamentous fungi were isolated in situ from 17 of 60 samples (28.3%). Considering the positive root canal isolates, the genus Aspergillus was isolated from 7 samples (41%); 4 species were identified: Aspergillus ustus, A. granulosus, A. niger, and A. sydowii. Emericella quadriluniata, sexual form of Aspergillus, was isolated from 1 sample. Penicillium species (Penicillium implicatum, P micsynvisk, P lividum, and P citrionigrum) were isolated from 4 samples (24%). Fusarium species (Fusarium moniliforme and F melanochorum) were isolated from 2 samples (12%). The species Aureobasidium pullulans, Exophiala jeanselmei, Eurotium amstelodame, and Cladosporium sphaerospermum were isolated from 1 sample each. Conclusions: The root canals of teeth with pulp necrosis and periapical lesions might present positive culture for filamentous fungi. (J Endod 2010;36:626-629)