Bacteroides, Prevotella, and Porphyromonas species: a review of antibiotic resistance and therapeutic options.

Recent basic and clinical research efforts have shed more light on the taxonomy, microbiology, epidemiology, antimicrobial susceptibility and treatment of Bacteroides, Prevotella, and Porphyromonas species. Of all anaerobic bacteria, Bacteroides is the most frequently isolated pathogen from clinical specimens, including blood. Bacteroides, Prevotella and/or Porphyromonas species have been isolated from clinical specimens in cases of infection from almost all anatomic sites. Several multicentre surveys have documented an alarming gradual increase of resistance rates of Bacteroides, Prevotella and Porphyromonas species worldwide. Antimicrobial agents active against >99% of clinical isolates of Bacteroides are metronidazole, chloramphenicol and carbapenems. Agents active against 95-99% of Bacteroides fragilis isolates are the beta-lactam/beta-lactamase inhibitor combinations. B. fragilis group species other than B. fragilis are more likely to be resistant to beta-lactam/beta-lactamase inhibitor combinations than B. fragilis.