Study On Rapid Diagnosis Of Tuberculous Wound With Paraffin Tissue

Objective:To explore the application value of melting curve method in the identification of bacteria species and drug resistance analysis in paraffin tissue of tuberculous wound.Methods:tuberculous wound will conform to the criteria for the paraffin group,42 cases of chronic wound paraffin 39 cases,acute wound paraffin tissue 40 cases,paraffin section after dewaxing extract DNA,use melting curve method for mycobacterium tuberculosis nucleic acid detection and identifying mycobacteria strains,and mycobacterium tuberculosis fluoroquinolone,isoniazid,rifampicin,streptomycin and ethambutol resistant mutation analysis.Results:The nucleic acid test of Mycobacterium tuberculosis complex group showed that in 42 cases of tuberculous wound,32 cases were positive and 10 cases were negative,the positive rate was 76.19%.Among the 32 cases,28 cases were Mycobacterium tuberculosis and 1 case was Mycobacterium bovis,and the specific classification could not be determined in 3 cases.Among the 39 chronic wounds,0 cases were positive and 39 cases were negative.Among the 40 cases of acute wound,0 cases were positive and 40 cases were negative.Fisher’s exact probability method was used to test,and there was a significant difference between the three groups(P<0.01),and there was a significant difference between chronic and acute wounds and tuberculous wounds(P<0.01),and there was no significant difference between chronic and acute wounds(P>0.05).Among them,8 cases with ct<20 were selected for drug resistance analysis:1 case was resistant to isoniazid;The drug-resistance mutation was located in the INHA promoter region(-17～-8),and was resistant to streptomycin.The drug-resistance mutation was located in the RPSL codon 43.One patient was resistant to isoniazid,and the mutation of resistance was KATG gene deletion.The other 6 patients were sensitive to streptomycin,isoniazid,ethambutol,fluoroquinolones and rifampicin.In the tuberculosis wound group,chronic wound group and acute wound group,89 samples with negative nucleic acid test of Mycobacterium tuberculosis complex group were identified for non-tuberculosis Mycobacterium strains.Among the 10 samples in the tuberculosis wound group,3 cases were detected for Mycobacterium flavarina,1 case was detected for Mycobacterium gordonii,and 6 cases contained no Mycobacterium.Among the 39 samples from the chronic wound group,6 cases were found to be Mycobacterium tartaris,4 cases were found to be Mycobacterium Gordon,18 cases were found to be other Mycobacteria,and 11 cases were found to be Mycobacterium free.None of the 40 patients in the acute wound group contained Mycobacterium.The results of mycobacterium detection were counted as positive,while those without mycobacterium detection were counted as negative.Fisher’s exact probability method and chi-square test showed no significant difference between the tuberculous wound group and the chronic wound group(χ2=3.551,P=0.075).P<0.01 in the chronic wound group and the acute wound group,and P<0.01 in the tuberculous wound group and the acute wound group,showing significant differences.Conclusions:The method of melting curve can be used to identify and analyze drug resistance of mycobacterium in paraffin tissue of tuberculous wound quickly and accurately.The method is simple and inexpensive,and it is especially suitable for popularization and application in primary hospitals.