Black-pigmented Bacteroides spp. in human apical periodontitis

Area of Science:

• Microbiology
• Endodontics
• Infectious Diseases

Background:

• Black-pigmented (BP) Bacteroides species are anaerobic bacteria often found in oral infections.
• Their role in human dental root canal infections, particularly apical periodontitis, requires further investigation.

Purpose of the Study:

• To determine the incidence and species distribution of BP Bacteroides in human root canal infections.
• To correlate the presence of specific BP Bacteroides species with clinical symptoms (acute vs. asymptomatic apical periodontitis).
• To assess the in vitro susceptibility of isolated BP Bacteroides strains to penicillin.

Main Methods:

• Culturing and identification of anaerobic bacteria from 62 human root canal infections.
• Clinical data collection on symptoms (acute or asymptomatic apical periodontitis).
• Antimicrobial susceptibility testing against penicillin G.

Main Results:

• BP Bacteroides were found in 31 of 62 infections, always as part of mixed anaerobic flora.
• Bacteroides intermedius (24%) and B. denticola (19%) were the most frequent species.
• Asaccharolytic species (B. gingivalis, B. endodontalis) were found in 8 cases and only in acute infections; B. intermedius occurred in both symptomatic and asymptomatic cases; B. denticola was more common in asymptomatic cases.
• Penicillin V treatment showed no significant effect on symptom development within the first week of endodontic therapy.

Conclusions:

• BP Bacteroides species are frequently isolated from human root canal infections, both symptomatic and asymptomatic.
• Specific BP Bacteroides species exhibit different associations with acute versus asymptomatic apical periodontitis.
• The limited penicillin susceptibility data suggests potential resistance in some strains, and clinical penicillin V therapy did not impact early symptom development.