A Study On The Treatment Outcome And Genotyping Of Isoniazid-Resistant Tuberculosis Patients

BackgroundIsoniazid has high bactericidal activity,is the core drug for the treatment of tuberculosis,and also plays a vital role in preventing tuberculosis.However,the isolated monoresistance of TB patients to isoniazid is often ignored.Meanwhile,the high resistance of TB patients to isoniazid shown in the baseline survey of TB resistance in China is worrisome.Mycobacterium tuberculosis is very prone to drug resistance,and treatment for TB often requires a combination of drugs to improve the success rate of treatment.However,the vast majority of patients with isoniazid-resistant tuberculosis(HR-TB)are treated with the standard regimens recommended by the World Health Organization(WHO)because they were not identified,and the bactericidal efficacy of isoniazid contained in the regimens for these patients will be greatly reduced,thus possibly leading to adverse treatment outcomes.In2018,WHO recommended adding the second-line drug levofloxacin(Lfx)to the treatment regimen of HR-TB to improve the treatment effect,but the drug resistance level of HR-TB to Lfx has not been reported.Based on this,this study studied the relationship between HR-TB and adverse treatment outcomes by comparing the differences in treatment outcomes between patients with isoniazid-resistant TB(HR-TB)and patients with isoniazid-sensitive TB(HS-TB).Nucleic acids extracted from the patients’strains were collected for molecular typing experiments to understand the transmission pattern of mycobacterium and the genotype distribution of the strains.We used the drug sensitivity test to detect the resistance of HR-MTB to Lfx to understand the resistance of HR-TB to the second-line drug Lfx in our province.MethodsTuberculosis patients determined to be sensitive to rifampicin and resistant to isoniazid by drug sensitivity test(DST)were collected as the HR-TB,and patients sensitive to both rifampicin and isoniazid were selected as the HS-TB according to the regional information of the HR-TB.The two groups of patients were compared and analyzed in terms of demographic information,disease condition,treatment rigements,treatment outcomes,etc.,to understand the relationship between risk factors such as advanced age,migrant workers,tuberculosis treatment history,lung cavity and isoniazid resistance,as well as the similarities and differences between HR-TB and HS-TB in treatment rigements and treatment outcome.Nucleic acids extracted from the biological specimens of the above-mentioned patients were collected to form the sample library for the molecular typing experiment in this study.HR-MTB and HS-MTB strains were genotyped by 24-loci MIRU-VNTR and Spoligotyping method respectively and the results of two groups strains were compared.The data of the tests were dealt with cluster analysis by http://www.miru-vntrplus.org.The genotyping results of the samples were combined with the corresponding patient information to understand the influence of infection with different genotypes of strains on the treatment outcome of patients.We used the drug sentitive test(appropriate concentrations)to test the resistance of the strain to levofloxacin in order to understand the resistance level of HR-MTB to Lfx in our province.In order to understand the influence of age,sex,occupation and other factors on Lfx resistance and the transmission mode of levofloxacin resistant strains in our province,drug resistance information of Lfx was combined with patient information and strain typing results.In this study,Excel 2019 was used to preprocess the data,and then the data were poured into SPSS 23.0 for statistical analysis.Chi-square test and Fisher’s precision probability test were used for comparison between groups,and multivariate analysis was used to understand the risk factors that might lead to adverse treatment outcomes for HR-TB.P<0.05 was considered statistically significant.Results1.A total of 120 HR-TB patients were collected in this study,and 193 HS-TB patients were matched according to the regional information in a ratio of 1:1.5.There was no significant difference in age,gender,occupation and other demographic information between the two groups(P>0.05).And there was no significant difference in tuberculosis treatment history,pulmonary cavity,severe tuberculosis and other conditions between the two groups(P>0.05).The proportion of patients using WHO recommended standard treatment regimens was similar between the two groups,and the difference was not statistically significant(P>0.05).In this study,the incidence of adverse treatment outcomes for HR-TB was 10.0%,of which 4 cases failed treatment,2 cases were transferred to MDR treatment,and 6 cases died;the incidence of adverse treatment outcomes for HS-TB was 3.6%,of which 1 case failed treatment,1 case were transferred to MDR treatment and 5 cases died.There was a statistical difference in the incidence of adverse treatment outcomes between the two groups(χ2=5.271,P=0.028).The risk of adverse treatment outcomes for HR-TB was 2.95 times that of HS-TB.And we found that advanced age and retreatment were risk factors for adverse treatment outcomes of HR-TB,with OR values of 12.85 and 19.13,respectively.2.The clustering rates of HR-MTB and HS-MTB were 17.5%(14/80)and 16.7%(20/120)by24-loci MIRU-VNTR,and there was no significant difference in the clustering rates between the two groups(χ~2=0.024,P>0.05).A total of 23 strains in the cluster of strains showed strong temporal and spatial connections.A total of 23 strains in the cluster of strains showed strong spatio-temporal connections.Among them,two drug resistance surveillance sites showed high recent transmission rates,which were 32.7%and 13.5%respectively.3.In this study,Beijing-family genotype was the main epidemic strain,accounting for 83.7%in the HR-MTB and 80.0%in the HS-MTB.The proportion of Beijing-family genotype strains in the two groups was similar.The incidence of adverse treatment outcomes in HR-TB patients infected with Beijing family genotype strains was 13.8%,and there were no adverse treatment outcomes in patients infected with non-Beijing family strains.In HS-TB,the incidence of adverse treatment outcomes of Beijing family strains was 1.1%,and that of non-Beijing family strains was 4.3%,with no statistical significance(P>0.05).The recurrence rates of HR-TB patients infected with Beijing family strains and those infected with non-Beijing family strains were both 7.7%,and the recurrence rates of HS-TB patients were 8.8%and 4.3%,respectively,and the difference was not statistically significant(P>0.05).In this study,the Hunter-Gaston Index(HGI)of 24 loci MIRU-VNTR was0.9972 for all strains,and the HGI of Spoligotyping was 0.4276.The HGI of Spoligotyping method was lower than that of MIRU-VNTR.4.64 HR-MTB strains were recovered successfully,and the rate of Lfx resistance was 21.9%.The resistance to Lfx of HR-MTB isolates was related to the occupation of patients,as the proportion of farmers and migrant workers in Lfx resistant TB was significantly lower than that in Lfx sensitive TB(P=0.017).Combining levofloxacin resistance information with strain genotypes revealed that more than half of the cases of levofloxacin resistant TB were due to recent transmission.Conclusion1.In this study,the age,gender,occupation and other factors of the patients were not related to isoniazid resistance,and the treatment regimens used for HR-TB was similar to HS-TB.Patients with HR-TB using standard treatment regimens was more prone to adverse treatment outcomes(treatment failure,transferred to MDR,and death),but the recurrence rate was not different from that of HS-TB.2.The HGI of 24 loci MIRU-VNTR was higher than that of Soligotyping method,and the combination of the two genotyping methods could achieve better effect.In this study,Beijing family genotype was the main epidemic strain,accounting for 81.5%,but there was no statistical correlation between Beijing family genotype and strain resistance to isoniazid,nor was it related to the treatment outcome of patients.3.HR-TB in Jiangsu Province had a high drug resistance rate of 21.9%to Lfx,and more than half of the Lfx resistant strains were caused by recent transmission,suggesting that the prevention and control work of tuberculosis in Jiangsu Province should strengthen the control of recent transmission.