ANTIBIOTIC THERAPY IN TREATING PERIODONTAL DISEASES

理想情况下，旨在控制致病性口腔微生物的疗法将抑制或消除这些微生物，留下稳定的宿主相容性微生物群。然而，有时，消除牙周病原体的尝试会导致微生物群的不期望的变化。其中两个最明显的是在口腔微生物群中不常见的致病物种的过度生长和抗生素耐药物种的出现。该项目将关注用于控制牙周感染的治疗方法，特别是抗生素治疗的安全性。近期目标是确定抗生素治疗对牙周微生物群组成和抗生素耐药性的影响。第一个目的是通过使用生物标记板杂交监测120种细菌的水平来确定抗生素治疗如何改变龈下微生物群的组成。将在基线、治疗完成时和治疗后1年，对24例接受洁治和根面平整（SCR）、SCR+局部四环素或SCR+全身阿莫西林和甲硝唑治疗的受试者的合并龈下菌斑样本中的龈下菌种进行检查。第二个目标是确定抗生素治疗如何影响菌斑细菌的抗生素耐药基因型和表型。目标1所述的三组中的12名受试者将在每个时间点挑选60个菌落。将通过16S rRNA测序的Checkboard杂交鉴定分离株，并通过Southern杂交确定抗生素耐药基因型。将通过平板培养确定抗生素耐药表型。将确定对多种抗生素具有耐药性的物种，并提供给检查耐药基因的合作者。

Ideally, therapies designed to control pathogenic oral microorganisms will suppress or abolish those organisms, leaving a stable host-compatible microbiota in place. At times, however, attempts to eliminate periodontal pathogens lead to undesired changes in the microbiota. Two of the most obvious are overgrowth of pathogenic species not commonly found din high numbers in the oral microbiota and the emergence of antibiotic resistant species. This Project will be concerned with the safety of therapies, particularly antibiotic therapies, employed to control periodontal infections. The immediate goal is to determine the consequences of antibiotic therapy on the composition and antibiotic resistance of the periodontal microbiota. The first aim is to determine how antibiotic therapy shift the composition of the subgingival microbiota by monitoring levels of 120 bacterial species using Checkerboard hybridization. Subgingival species in pooled subgingival plaque samples will be examined at baseline, at the completion of therapy, and at 1-year post therapy for 24 subjects treated by either scaling and root planing (SCR), SCR plus local tetracycline, or SCR plus systemic amoxicillin and metronidazole. The second aim will determine how antibiotic therapy affects antibiotic resistance genotype and phenotype of plaque bacteria. Twelve subjects in the three groups described for Aim 1 will have 60 colonies picked for each time point. The isolates will be identified by Checkboard hybridization of 16S rRNA sequencing, and the antibiotic resistance genotype will be determined by Southern hybridization. Antibiotic resistance phenotype will be determined by plate culture. Species that are resistant to multiple antibiotics will be identified and made available to collaborators examining resistance genes.