This study assessed the subgingival occurrence of the flagellated, Gram-negative, anaerobic rod Centipeda periodontii in
chronic periodontitis and periodontal health/
gingivitis with species-specific
nucleic acid probes, and evaluated the in vitro resistance of subgingival isolates to therapeutic levels of
amoxicillin,
metronidazole, and
doxycycline. Subgingival plaque biofilm specimens from 307 adults with
chronic periodontitis, and 48 adults with periodontal health/localized
gingivitis, were evaluated with
digoxigenin-labeled, whole-chromosomal,
DNA probes to C. periodontii ATCC 35019 possessing
a 10(4) cell detection threshold. Fifty-two C. periodontii subgingival culture isolates were assessed on
antibiotic-supplemented enriched Brucella blood
agar for in vitro resistance to either
amoxicillin at 2 µg/ml,
metronidazole at 4 µg/ml, or
doxycycline at 2 µg/ml. A significantly greater subgingival occurrence of C. periodontii was found in
chronic periodontitis subjects as compared to individuals with periodontal health/
gingivitis (13.4 vs. 0 %, P < 0.003), although high subgingival counts of the organism (≥ 10(6) cells) were rarely detected (1.3 % of
chronic periodontitis subjects). In vitro resistance was not found to
amoxicillin or
metronidazole, and to
doxycycline in only 2 (3.9 %) of the 52 C. periodontii clinical isolates studied. These findings indicate that C. periodontii is not a major constituent of the subgingival microbiome in
chronic periodontitis or periodontal health/
gingivitis. The potential contribution of C. periodontii to periodontal breakdown in the few
chronic periodontitis subjects who yielded high subgingival levels of the organism remains to be delineated. C. periodontii clinical isolates were susceptible in vitro to therapeutic concentrations of three
antibiotics frequently used in treatment of human
periodontitis.