| Objective 1.To investigate and analyze the prevalence of drug resistant tuberculosis in southern Xinjiang.2.To study the genotypes and their relationship with drug resistance in Mycobacterium tuberculosis isolated from southern Xinjiang.3.To analyze the distribution of mutations related to drug resistance of four major anti-tuberculosis drugs including isoniazid(INH),rifampicin(RMP),ethambutol(EMB),streptomycin(STR)in clinical isolates of M.tuberculosis isolated from tuberculosis patients in southern Xinjiang and their correlation with drug resistance.Methods 1.From January 2017 to December 2018,inpatients/outpatients with tuberculosis over the age of 16 years old who were confirmed and registered in hospitals were continuously included as theresearch objects.The sputum samples of tuberculosis patients were used to culture for mycobacterium and the M.tuberculosis isolates were identified and drug susceptibilitytests were carried out.2.A total of 346 clinical isolates of Mycobacterium tuberculosis collected in the first part of this study were randomly selected as the research objects for this part,and their DNA was extracted and genotyping was performed by Spoligotyping method.3.By whole genome sequencing,comparative genomics was used to analyze the genome sequences of 346 M.tuberculosis from southern Xinjiang,and the mutations in 18 known drug-resistance related gene regions were identified.The incidence of non-synonymous mutations in the target genes in the drug-sensitive or drug-resistant strains was calculated.Results 1.The total drug resistance rate,mono-drug resistance rate,poly-drug resistance rate,multi-drug resistance rate,pre-extensively drug resistance rate and extensively drug resistance rate of 904 tuberculosis patients were 46.1%,14.3%,18.9%,12.9%,4.4%and 1.2%,respectively.The incidence of these types of drug resistance in retreated patients was higher than that in new patients,and the differences were all statistically significant(P values were all<0.05).The total drug resistance rates of each drug were as following:INH 30.0%,STR 19.9%,RMP 18.6%,moxifloxacin(Mfx)14.4%,levofloxacin(Lfx)12.8%,rifabutin(Rfb)8.8%,rifapentine(Rpt)8.4%,EMB 4.9%,kanamycin(KAN)4.0%,amikacin(AMK)3.0%,p-aminosalicylic acid(PAS)1.1%,CAP 0.9%,Dip 2.1%,Pto 0.9%,Clr 0.8%,Cfz 0.3%;the resistance rates of M.tuberculosis to INH,RMP,Rpt,Rfb,EMB,STR,Lfx,Mfx and other common anti-tuberculosis drugs in retreatment patients were all higher than that in the new patiens group,the differences were all statistically significant(P values were all<0.05).There were significant differences in the resistance rate of pre-XDR(pre-extensively drug resistant tuberculosis)in new patients and the resistance rates of total drug resistance,STR,RMP,Rpt,MDR(multi-drug resistant tuberculosis)and XDR(extensively drug resistant tuberculosis)in retreatment patients among different age groups(P values were all<0.05).The total drug resistance rate,the resistance rates of Mfx,KAN,AMK,PAS and poly-drug resistant tuberculosis in the farmers were all higher than those in the non-farmers,while the resistance rates of RMP,Rpt,Rfb,STR,MDR and pre-XDR in the non-farmers were higher than those in the farmers,there were statistically significant differences among different occupational groups(P values were all<0.05).2.The 346 M.tuberculosis isolates could be divided into two large genotypes,Beijing genotype and non-Beijing genotype,accounting for 202(58.4%)and 144(41.6%),respectively.The non-Beijing genotypes included CAS1-Delhi(47,13.6%),Ural-2(31,8.9%),T1(12,3.5%),EAI(11,3.2%),T2(5,1.4%),T3(3,0.9%),T2(2,0.6%),H3(2,0.6%),LAM9(2,0.6%),H1(1,0.3%),Ural-1(1,0.3%)and unkown types(27,7.8%)respectively.There were no significant differences in gender,residence and treatment history between patients infected with Beijing genotype and non-Beijing genotype,but the proportion of Beijing genotype infection in non-farmers was higher than that in farmers(68.2%VS 52.5%,χ2=8.19,P<0.01).Compared with other age groups,the infection rate of Beijing genotype was higher in the group under 30 years old(75.0%)(χ2=11.72,P<0.01).The prevalence of the total drug resistance of Beijing genotype strains were higher than those of non-Beijing genotype strains(52.1%VS 39.1%),as well as MDR(19.3%VS 7.6%),RMP resistance(23.3%VS.9.0%),EMB resistance(10.9%VS 4.9%)and Mfx resistance(32.7%VS 13.2%),and the differences were all statistically significant(P values were all<0.01).Analysis of drug resistance related factors showed that Beijing genotype and treatment history presented significantly increased risks for developing any-drug resistance and MDR with odds ratios(ORs)of 1.89(95%CI=1.16-3.09,P<0.01)and 4.02(95%CI=1.78-9.09,P<0.01),respectively.Retreated patients presented significantly increased risks for developing any-drug resistance and MDR with ORs of 1.65(95%CI=1.02-2.68,P=0.04)and 6.9(95%CI=3.16-15.12,P<0.01),respectively.3.The whole genome sequencing results showed that the katG315 mutation S315T accounted for 41.5%(44/106)INH resistance,whilst mutations in the inhA promoter and oxyR-ahpC intergenic region accounted for 7.5%(8/106)and 9.4%(10/106)INH resistance respectively.There was no significant difference in gene mutation frequencies of iniA,iniB,iniC,ndh,kasA and efpA between INH resistant and susceptible strains(P values all>0.05).The codon with the highest frequency of rpoB gene was 450(36/60,60.0%),followed by 445(11/60,18.3%),430(8/60,13.3%)and 435(4/60,6.7%).The most common mutation locus of embB gene was Met306(16,55.2%).There was no statistical difference in the mutation frequencies of embC and embA genes between EMB resistant and susceptible strains(P>0.05).The most frequent mutation in the 530 and 912 loops of rrs gene among STR resistant strains mutations was A514C(8,11.4%),followed by A908C(4,5.7%)and C517T(1,1.4%).The most frequent rpsL mutation locus was K43R(25,35.7%),followed by K88R(9,12.9%).Conclusions 1.The drug resistance of tuberculosis in southern Xinjiang was serious,and effective prevention and control measures should be taken.2.The Beijing genotype strains were the main prevalent strains in southern Xinjiang.Meanwhile,the non-Beijing genotype strains in this area were polymorphic;Beijing genotype in this area was correlated with total drug resistance,MDR,RMP-,EMB-and Mfx-resistance.The M.tuberculosis genotype and history of treatment were the main risk factors for the occurrence of drug-resistance and MDR.3:Mutations in katG,rpoB,embB,rpsL,rrs 530 and 912 loop contributed to the anti-tuberculosis drug resistance in the southern Xinjiang,the common mutations in the five genes were rpoB S450L,katG S315T,embB Met306,rrs A514C,rpsL K43R and rpsL K88R. |
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