한국인 구강에서 분리된 세균의 동정

Abstract

The aim of this study was to identify bacteria isolated from a Korean oral cavity and to determine their antimicrobial susceptibility against eight antibiotics. The bacterial strains were obtained from the Korean Collection for Oral Microbiology (KCOM). The bacteria were identified by comparing 16S rDNA sequences at the species level. The data showed that 77 bacterial strains were predominantly identified as streptococci (49.4%) and staphylococci(14.3%). Among the Mitis group streptococci, the 16S rDNA homogeneity was too high to discriminate between clinical strains at the species level. So, phylogenetic analyses of the Mitis group streptococci were evaluated using the partial gene sequence comparison of 16S rDNA, rpoB, sodA, and groEL. Phylogenetic data based on the nucleotide sequences of the four genes showed that Mitis group streptococci were not discriminated at the species level. Minimum inhibitory concentrations (MIC) were determined using a broth dilution assay to test the sensitivity of the bacteria isolated from a Korean oral cavity against eight antibiotics. The MIC values of the oral bacterial strains against antibiotics were different. Streptococci showed sensitivity toward clindamycin and vancomycin and were resistant to tetracycline. Staphylococci also showed sensitivity toward clindamycin, cefuroxime axetil and vancomycin and were resistant to penicillin antibiotics. Gram-negative bacterial strains showed sensitivity toward tetracycline and were resistant to clindamycin. The resulting data regarding the antimicrobial susceptibility test are useful in the decision for antibiotic treatments and needed to prevent the misuse or abuse of antibiotics.