A Study Of Genotyping In Non-tuberculosis Mycobacteria Superiority Strains In Dali By MLVA Technique

Objective: Using 16 SrRNA gene to understand the prevalence of common pathogenic non-tuberculous mycobacteria in Dali,Yunnan.To explore the application of Multiple locus variable-number Tandem-repeat(MLVA)genotyping in Dali,Yunnan.Methods : 1.Collection of pathogenic non-tuberculous mycobacteria(NTM)preliminarily identified by P-Nitrobenzoic acid(PNB)and 2-Thiophenecarboxylic acid hydrazide TCH in Dali,Yunnan.The sputum specimens of the patients were isolated and cultured,and the well-grown NTM strains were subjected to polymerase chain reaction(PCR)and agarose gel electrophoresis using 16 SrRNA and hsp65 multi-target genes,and the gel was recovered and sequenced.The molecular species of the clinical isolates were then identified by comparing the two primers with Blast.2.Genotyping studies on well-cultured non-tuberculous mycobacterial strains identified by molecular species using the MLVA method.The results obtained by the experiment were digitized and clustered using BioNumerics(6.6)softwar.Result:1.After identification of molecular strains using 16 SrRNA and hsp65 primers,the results showed that there were 10 non-tuberculous mycobacteria,of which M.avium was common,8 strains,followed by There are 2 strains of Mycobacterium abscessus..It can be seen that Mycobacterium avium is the dominant strain in Dali area.2.Cluster analysis showed that Mycobacterium avium was divided into 4 groups(A,B,C,D)and 7 genotypes.Group A has 2 genotypes,2 strains,accounting for 25% of the total number of strains;Group B has 3 genotypes,4 strains,accounting for 50% of the total number of strains;Group C has 1 genotype,with 1 The strain accounted for 12.5% of the total number of strains;the D group had one genotype,and one strain,accounting for 12.5% of the total number of strains.Among the 8 strains of M.avium,there were one cluster in B group,and there were 2 strains,the clustering rate was 25%(2/8),and 6 strains were not clustered,accounting for 75%(6/8).There are no clusters in the A,C,and D groups.Conclusion: 1.16 SrRNA is commonly used as the gold standard in the identification of non-tuberculous mycobacteria species,and the dominant flora of Mycobacterium avium is mainly in Dali area.2.Non-tuberculous mycobacteria in Dali area have high DNA gene polymorphism.From the cluster analysis chart,MLVA genotyping can be divided into 4 gene groups,and the main epidemic group is B group.