Delayed-onset infections after impacted lower third molar extraction: involved bacteria and sensitivity profiles to commonly used antibiotics

Objectives. The objectives of this study were to identify the bacteria involved in delayed-onset infections after lower third molar removal and to determine the most suitable antibiotic for such complication. Study Design. Bacterial samples were collected from 13 patients who developed delayed-onset infections after lower third molar extraction. After the identification of the bacterial isolates, the in vitro antimicrobial susceptibility of the isolated strains was determined. Results. A total of 11 patients (12 samples) were finally included in the study. Up to 7 bacteria genera were identified. Fusobacterium sp. was present in 11 patients, Prevotella sp. in 8 cases, and Peptostreptococcus sp. in 7. Some strains of these bacteria were not susceptible to amoxicillin, amoxicillin/clavulanate, and metronidazol, whereas no resistances were found to clindamycin. Conclusions. Fusobacterium sp., Prevotella sp., and Peptostreptococcus sp. are frequently present in delayed-onset infections after lower third molar removal. Based on the results of the microbial susceptibility tests, clindamycin seems to be the most adequate antibiotic for the treatment of this complication. (Oral Surg Oral Med Oral Pathol Oral Radiol 2012;114:43-48)