Comparação por análise molecular da diversidade bacteriana da saliva de pacientes com diferentes índices de higiene bucal

Abstract

The complex microbiota of the oral cavity has been intensively studied and saliva is characterized by microorganisms which colonize different regions of mouth, such as tongue, supragengival and subgingival biofilm. Considering this, the purpose of this study was to evaluate the bacterial diversity of the saliva of patients with different levels of oral hygiene according to the Silness, Löe index. In this research, two genomic libraries of saliva source from 15 patients each were constructed. The pooled samples differ in the average index of Silness, Löe being considered as high or low index within the rate 1.0 to 3.0 and 0 to 0.5, respectively. The DNA saliva was extracted by phenol / chloroform method and 16S rRNA gene for the microorganisms of each sample were amplified and cloned. The sequences obtained were compared to those from sequences of the GenBank NCBI and RDP. The library resultant from saliva of patients with high level of dental biofilm showed 23 OTUs grouped as five known genus: Streptococcus, Granulicaella, Gemella, Peptostreptococcus and Veillonella besides 33.3% of uncultured bacteria. The Library made from saliva of patients with low level of dental biofilm, was significantly different from its counterpart (p = 0.000) and was composed by 42 OTUs, distributed among 11 known genus: Streptococcus, Granulicaella, Gemella, Veillonella, Oribacterium, Haemophilus, Escherichia, Neisseria, Prevotella, Capnocytophaga, Actinomyces, and 24.87% of uncultured bacteria. The genus Streptococcus was the more prevalent in the two libraries, constituting 79.08% of the first and 73.64% the second. In conclusion, patients with low dental biofilm index have saliva with higher bacterial diversity than patients with high dental biofilm index, and despite most uncultivated species aggregate with Steptococcus, they still are new and unknown microorganisms