Estudo bacteriológico de lesões periapicais

Periapical tissue from 30 individuals requiring dental surgery was examined histologically and cultured for the presence of bacteria. A total of 137 strains of bacteria were isolated and of the isolates, 65.7% were strict anaerobes, 29.2%, facultative anaerobes and 5.1%, strict aerobes. Fusobacterium nucleatum was the species most frequently isolated, followed by pigmented strict anaerobes, Peptostreptococcus sp and Streptococcus mitis. In all cases more than one bacterial species was found. The histological analysis demonstrated prevalence of periapical granuloma. Fusobacterium nucleatum isolated from 16 patients was tested for susceptibility to penicillin, cefoxitin, erythromycin, metronidazole and tetracycline. All strains were susceptible to cefoxitin, metronidazole and tetracycline and the resistance rates to penicillin and erythromycin were 12.5 and 68.8% respectively. The resistance rates of F. nucleatum, an important bacterium in periapical infection to penicillin and erythromycin emphasize the need to further study antimicrobial resistance of bacteria isolated from odontogenic infections.