Identification Of Clinical Atypical Bacteria By16S RRNA Gene Sequencing

Objective: Applying16S rRNA gene sequence analysis toidentification of15experiment bacteria in clinical microorganismlaboratory which cannot be identified accurately by traditionalidentification method, taking it as a necessary supplement for routinebacteria identification.Method: After confirming the experiment accuracy of5standardbacteria of clinical microorganism department, selecting15inaccurateidentification bacteria by routine identification method in microorganismlaboratory（including gram positive coccus，gram positive bacillus andgram negative bacillus）. Extracting DNA, amplifying16S rRNA genefragment with common primer, sending PCR product to Huada GeneCompany for sequence, then comparing the16S rRNA sequence with thatof16S rRNA GENBANK. When the homology of the two16S rRNAsequences was <99%and≥95%, they were defined as the same genus;when the homology was≥99%,they were defined as the same species.Results: The homology of14strains（93.3%）in15experimentbacteria were≥99%,they were identified to species successfully, including Nocardia farcinica，Escherichia coli，Staphylococcus arlettae，Bacteroidesfragilis，Citrobacter freundii，Bacillus pumilus，Vagococcus fluviali，Curtobacterium pusillum， Aggregatibacter actinomycetemcomitans,Granulicatella adiacens;1strain（6.6%）was identified to genus with thehomology of97%,which was assigned to Brachybacterium.Conclusion: For bacteria which cannot be identified accurately bytraditional identification in clinical microorganism laboratory，identification with16S rRNA gene sequence analysis has the character ofaccuracy，convenience and speediness. It can be applied to identify clinicalatypical bacteria, infrequent bacteria and new bacteria.