Bacterial diversity in synovial fluids of patients with TMD determined by cloning and sequencing analysis of the 16S ribosomal RNA gene

Objective. The purpose of this study was to examine the presence of bacterial in synovial fluids from patients with temporomandibular joint disorder (TMD) by polymerase chain reaction (PCR) targeting the 16S ribosomal RNA (rRNA) gene, followed by cloning and sequencing. Study design. Universal bacterial primers were used to amplify 16S rRNA genes in 28 synovial fluid samples from 27 patients with TMD (TMD group) as well as control subjects: 5 patients with dislocation of TMJ (non-TMD group). Subsequently, PCR amplicons were purified and cloned. Partial 16S rRNA sequences of the cloned insert were used to determine the species identities or closest relative by comparison with known sequences using GeneBank. Results. Nineteen (67.86%) of 28 samples from patients in the TMD group were identified with the presence of bacterial DNA by PCR. The 5 control samples from the nonTMD group were all negative in this study. After cloning and sequencing, a total of 11 bacterial species was detected, including Granulicatella adiacen (6 samples), Pseudomonas sp. (6 samples), Methylobacterium sp. (5 samples), and Beta proteobacterium (4 samples). Other species, such as Acidovorax sp., Bradyrhizobium sp., Sphingomonas, Streptococcus, Leptothrix sp. oral clone, Thiobacillus denitrificans, and Comamonadaceae bacterium, were also identified. Eight patients were found with mixed bacteria, with 2-4 bacteria per sample. The patients with fastidious bacteria such as Granulicatella adiacen and mixed bacteria were more likely to be older than 45 years (P <.05). Conclusion. A wide variety of bacteria, including some not previously reported associated with TMD, were identified in the synovial fluids from patients with TMD.