Objective The present study aims to investigate the distribution and antimicrobial susceptibilities of subgingival pathogenic bacteria from patients with chronic periodontitis. Methods The putative periodontal pathogens were isolated from subgingival plaque in patients with chronic periodontitis. Antimicrobial susceptibility of the bacteriato ten antimicrobial agents was measured by the agar dilution technique. Results A total of 262 bacterial strains wereisolated from the subgingival plaques of 68 patients with chronic periodontitis. Among the 262 isolates, Porphyromon gingivalis(66.2%) and Prevotella melaninogenica(60.3%) were the most predominant, followed by Actinobacillus actinomycetemcomitan(55.9%), Fusobacterius nucleatum(51.5%), Peptostreptococcus(45.6%), and so on. The tested strainswere highly susceptible to nitro imidazole drugs, and their susceptibility rates to metronidazole, tinidazole, and ornidazolewere over 90%. All isolates were susceptible to amoxicillin/clavulanate. Approximately 51% to 78% of the isolates were susceptible to azithromycin, minocycline, and clindamycin. Susceptibility to penicillin and erythromycin were only 2.3%and 17.9%, respectively. Conclusion Porphyromon gingivalis and Prevotella melaninogenica were the most frequently isolated putative periodontal pathogens in patients with chronic periodontitis in the Xiaoba district of Qingtongxia City, Ningxia. Amoxicillin/clavulanate and nitro imidazole drugs are useful alternatives against anaerobic bacteria involved inperiodontitis.
