ABSTRACT
<p><b>OBJECTIVE</b>To investigate the microbial changes on the greasy tongue coating of the patients with chronic gastritis and to explore the formation mechanism of greasy tongue coating.</p><p><b>METHODS</b>Forty cases of tongue coating samples from patients with chronic gastritis were collected, 20 cases of greasy fur (as the greasy fur group), 20 cases of non-greasy fur (as the non-greasy fur group), and 20 cases of tongue coating samples from healthy subjects (as the healthy control group). Using 16S rRNA gene denatured gradient gel electrophoresis (DGGE) the microbial population of the tongue coating was detected. The DGGE fingerprint of the bacterium on the tongue coating was obtained. After digitalized principle component analysis (PCA) and partial least squares (PLS-DA) were performed.</p><p><b>RESULTS</b>The microorganism compositions are different in the greasy fur group, the non-greasy fur group, and the healthy control group. (1) There were five significantly different bands between the greasy fur group and the non-greasy fur group, with the accuracy of 97.5% in judging the model. There were 8 significantly different bands between the greasy fur group and the healthy control group, with the accuracy of 95.0% in judging the model. There was no obvious difference between the healthy control group and the non-greasy fur group. (2) The brightness of band 8 was higher in the greasy fur group than in the non-greasy fur group and the healthy control group. It may be a new species closely associated with the formation of greasy tongue coating. Results of the sequence showed its nearest neighbor was Moraxella catarrhalis, but with the similarity of 96.2%. The brightness of band 10 was sequenced as the healthy control group > the non-greasy fur group > the greasy fur group. Results of the sequence showed it had 100.0% similarity to Rothia mucilaginosa (stick-slip Ross strain).</p><p><b>CONCLUSIONS</b>The bacteria species on band 8 may have a close correlation with the formation of greasy fur of chronic gastritis, while the bacteria species on band 10 may have a close correlation with the formation of non-greasy fur. They indicated the microbial changes in the oral cavity may be one of the formation mechanisms for greasy tongue coating.</p>