Li Y, Ge Y, Saxena D, Caufield P W
Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, NY 10010, USA.
J Clin Microbiol. 2007 Jan;45(1):81-7. doi: 10.1128/JCM.01622-06. Epub 2006 Nov 1.
The determination of the composition of the microbial community in the oral cavity is usually based on cultivation methods; however, nearly half of the bacteria in the saliva and the dental plaque are not cultivable. In this study, we evaluated the difference in oral microbial diversity between children with severe early-childhood caries (S-ECC) and caries-free (CF) controls by means of a cultivation-independent approach called denaturing gradient gel electrophoresis (DGGE). Pooled dental plaque samples were collected from 20 children aged 2 to 8 years. Total microbial genomic DNA was isolated from those subjects, and a portion of the 16S rRNA gene locus was PCR amplified by using universal primers. We observed that the mean species richness of the bacterial population was greater in the CF children (n = 12) (42 +/- 3.7) than in the S-ECC children (n = 8) (35 +/- 4.3); the difference was statistically significant (P = 0.005). The overall diversity of plaque samples as measured by the Shannon index was 3.5 for the S-ECC group and 3.7 for the CF group (P = 0.004). Differences in DGGE profiles were distinguished on the basis of a cluster analysis. Sequence analysis of excised DGGE bands consisted of 2.7 phylotypes, on average. After adjusting for the number of observed bands, we estimated that the S-ECC group exhibited 94.5 total phylotypes and that the CF group exhibited 113.4. These results suggest that the microbial diversity and complexity of the microbial biota in dental plaque are significantly less in S-ECC children than in CF children.
口腔微生物群落组成的确定通常基于培养方法；然而，唾液和牙菌斑中近一半的细菌是不可培养的。在本研究中，我们通过一种名为变性梯度凝胶电泳（DGGE）的非培养方法，评估了重度幼儿早期龋（S-ECC）儿童与无龋（CF）对照儿童口腔微生物多样性的差异。从20名2至8岁的儿童中收集混合牙菌斑样本。从这些受试者中分离出总微生物基因组DNA，并使用通用引物对16S rRNA基因位点的一部分进行PCR扩增。我们观察到，CF儿童（n = 12）（42 +/- 3.7）的细菌种群平均物种丰富度高于S-ECC儿童（n = 8）（35 +/- 4.3）；差异具有统计学意义（P = 0.005）。通过香农指数测量，S-ECC组菌斑样本的总体多样性为3.5，CF组为3.7（P = 0.004）。基于聚类分析区分了DGGE图谱的差异。切除的DGGE条带的序列分析平均由2.7个系统发育型组成。在调整观察到的条带数量后，我们估计S-ECC组共有94.5个系统发育型，CF组有113.4个。这些结果表明，S-ECC儿童牙菌斑中微生物群落的多样性和复杂性明显低于CF儿童。
