Azithromycin is an azalide antibiotic, which has a strong effect on a wide variety of oral bacteria. It is taken up by phagocytes and is released over a long period in the inflamed tissue. This study investigated the clinical and microbiological effects, and measured the drug concentration in gingival of periodontal patients systemically administered azithromycin. The subjects were 26 adults diagnosed with periodontitis and given azithromycin (zithromac®) 500 mg once daily for 3 days. Clinical parameters such as PD, GI, BOP and GCF were examined at days 0, 7, and 14, and subgingival plaque was collected by paper points at days 0, 4, 7 and 14. The total number of cultivable bacteria was counted and six of the periodontopathic bacteria —Porphyromonas gingivalis, Actinobacillus actinomysetemcomitans, Bacteroides forsythus, Prevotella intermedia, Prevotella nigresence, and Toreponema denticola—were assessed by the PCR method. The lining gingiva of periodontal pocket was collected by pocket curettage at days 4 and 7. The azithromycin concentration was measured by agar diffusion bioassay.
The total number of bacteria was significantly decreased at days 4 and 7, but was slightly increased at day 14. Continuous reduction of the six bacteria was recognized until day 14 by PCR. These bacteria were not detected at day 14 without Porphyromonas gingivalis. This result might be due to improvement of anaerobic condition caused by pocket reduction. The azithromycin concentration in the lining gingival tissues of periodontal pocket was 2.92±1.97μg/g at day 4 and 1.27±0.95μg/g at day 7. Half the drug concentration was still detected at 7 days after the first administration in inflamed gingiva.
These results indicate that azithromycin may be a useful adjunct agent for adult periodontitis. In the future, we will consider a new periodontal therapy using this behavior of azithromycin.
