Bacterial complexes and antibiotic recommendations

Objectives: The aim of the present study was to determine specific antibiotic regimens by comparing subgingival colonization patterns of 6 periodontopathic bacteria (Actinobacillus actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Eikenella corrodens (Ec), Bacteroides forsythus (Bf), Prevotella intermedia (Pi), and Prevotella nigrescens (Pn)) with published MIC₉₀ values and concentrations in gingival crevicular fluid (GCF) of different antibiotics. Methods: 188 patients with periodontitis were included in the study. Subgingival plaque samples from the teeth with the deepest pockets in each quadrant were taken with sterile curettes. Aa, Pg, Ec, Bf, Pi, and Pn were identified by PCR. Results: Twenty nine different bacterial complexes (BC) were identified. The analysis revealed 9 major BC (each > 3% of all patients): Pi, Pn, Pg, Ec, Bf (16,0%); Pn, Pg, Ec, Bf (14,9%); Pg, Ec, Bf (7,5%); Aa, Pi, Pn, Pg, Ec, Bf (7,5%); Pn, Ec, Bf (6,4%); Pg, Pi, Ec, Bf (6,4%); Ec, Bf (5,3%); Aa, Pn, Pg, Ec, Bf (5,3%); and none (3,7%). Twenty minor BC (each < 3% of all patients) were distributed over 27,1% of the patients. Based on the published data, five antibiotic regimens were found to be specific in the 29 BC identified: Metronidazole and Amoxicillin in 19 BC (72,9% of all patients); Amoxicillin in 2 BC (9,6%), Metronidazole in 4 BC (5,9%), Ciprofloxacin in 1 BC (0,5%), and Doxycycline in 2 BC (7,5%). Conclusions: The results of this study indicate that microbiological testing before therapy is necesssary for specific systemic antibiotic treatment.