Prediction of XDR/pre-XDR tuberculosis by genetic mutations among MDR cases from a hospital in Shandong, China

Evaluation of genetic mutations associated with phenotypic resistance to fluoroquinolones, bedaquiline, and linezolid in clinical Mycobacterium tuberculosis: A systematic review and meta-analysis

OBJECTIVES

The aim of the study was to update the classification of drugs used in multidrug-resistant tuberculosis (MDR-TB) regimens. Group A drugs (fluoroquinolones, bedaquiline (BDQ), and linezolid (LZD)) are crucial drugs for the control of MDR-TB. Molecular drug resistance assays could facilitate the effective use of Group A drugs.

METHODS

We summarised the evidence implicating specific genetic mutations in resistance to Group A drugs. We searched PubMed, Embase, MEDLINE, and the Cochrane Library for studies published from the inception of each database until July 1, 2022. Using a random-effects model, we calculated the odds ratios and 95% confidence intervals as our measures of association.

RESULTS

A total of 5001 clinical isolates were included in 47 studies. Mutations in gyrA A90V, D94G, D94N, and D94Y were significantly associated with an increased risk of a levofloxacin (LFX)-resistant phenotype. In addition, mutations in gyrA G88C, A90V, D94G, D94H, D94N, and D94Y were significantly associated with an increased risk of a moxifloxacin (MFX)-resistant phenotype. In only one study, the majority of gene loci (n = 126, 90.65%) in BDQ-resistant isolates were observed to have unique mutations in atpE, Rv0678, mmpL5, pepQ, and Rv1979c. The most common mutations occurred at four sites in the rrl gene (g2061t, g2270c, g2270t, and g2814t) and at one site in rplC (C154R) in LZD-resistant isolates. Our meta-analysis demonstrated that there were no mutations associated with BDQ- or LZD-resistant phenotypes.

CONCLUSION

The mutations detected by rapid molecular assay were correlated with phenotypic resistance to LFX and MFX. The absence of mutation-phenotype associations for BDQ and LZD hindered the development of a rapid molecular assay.

Epidemiology of extensively drug-resistant tuberculosis among patients with multidrug-resistant tuberculosis: A systematic review and meta-analysis

OBJECTIVES

To estimate the pooled proportion of extensively drug-resistant tuberculosis (XDR-TB) and pre-extensively drug-resistant tuberculosis (pre-XDR-TB) in patients with multidrug-resistant TB (MDR-TB).

METHODS

We systematically searched articles from electronic databases: MEDLINE (PubMed), ScienceDirect, and Google Scholar. We also searched gray literature from the different literature sources main outcome of the review was either XDR-TB or pre-XDR-TB in patients with MDR-TB. We used the random-effects model, considering the substantial heterogeneity among studies. Heterogeneity was assessed by subgroup analyses. STATA version 14 was used for analysis.

RESULTS

A total of 64 studies that reported on 12,711 patients with MDR-TB from 22 countries were retrieved. The pooled proportion of pre-XDR-TB was 26% (95% confidence interval [CI]: 22-31%), whereas XDR-TB in MDR-TB cases was 9% (95% CI: 7-11%) in patients treated for MDR-TB. The pooled proportion of resistance to fluoroquinolones was 27% (95% CI: 22-33%) and second-line injectable drugs was 11% (95% CI: 9-13%). Whereas the pooled resistance proportions to bedaquiline, clofazimine, delamanid, and linezolid were 5% (95% CI: 1-8%), 4% (95% CI: 0-10%), 5% (95% CI; 2-8%), and 4% (95% CI: 2-10%), respectively.

CONCLUSION

The burden of pre-XDR-TB and XDR-TB in MDR-TB were considerable. The high burdens of pre-XDR-TB and XDR-TB in patients treated for MDR-TB suggests the need to strengthen TB programs and drug resistance surveillance.

Fluoroquinolone resistant tuberculosis: A case report and literature review

Despite the advancements made in medicine and treatment of tuberculosis over the last century, it remains a significant healthcare challenge. It remains the leading cause of death from a single infectious agent and the ninth leading cause of death worldwide. A 23-year-old male with a history of tuberculosis treated in Nepal seven years prior, presented to the emergency department with one week of hemoptysis, fever, chills, night sweats and weight loss. A CT scan of the chest showed multiple cavitary lesions at the superior segment of the left lower lobe. He had persistent massive hemoptysis and required blood transfusions. He underwent bronchial artery embolization followed by lobectomy. He was ultimately diagnosed with fluoroquinolone-resistant tuberculosis, and required a prolonged intensive care unit with transfer to a regional tuberculosis center to successfully complete treatment.

Analysis of rrs gene mutations in amikacin resistant clinical isolates of Mycobacterium tuberculosis from Khyber Pakhtunkhwa, Pakistan

Tuberculosis is a major infectious disease caused by Mycobacterium tuberculosis complex. Antimicrobial drugs are used to control TB infections. Molecular mechanisms controlling resistance to second-line drugs are not completely understood and no endogenous information is available regarding these mechanisms. The present study reports mutational analysis of rrs gene in Mycobacterium tuberculosis isolates collected from Khyber Pakhtunkhwa province of Pakistan. A total of 499 Mycobacterium tuberculosis isolates were analyzed for resistance against amikacin. Thirty resistant isolates were selected for mutational analysis in rrs gene. Among the 30 amikacin resistant isolates of Mycobacterium tuberculosis, 9 (30%) had mutation in the hotspot region of rrs gene. The predominant mutation was 1401A > G which was observed in 5 isolates. Maximum number of mutations was observed in isolate 6 and isolate 16 with six different mutations each. Mutations in isolate 6 included 1260G > A, 1278A > T, 1278_1279insT, 1300C > T, 1321G > A and 1445C > T. Mutation in isolate 16 included 1255_1256insA, 1364_1365insG, 1384_1385insA, 1880_1881insT, 1487G > A, and 1493delA. The mutation 1263G > A was observed in isolate 1. Isolate 2 had the 1484G > T mutation. The findings could be used as reference for future endures. It was evident from the results that mutations in rrs gene do not always contribute to amikacin resistance; hence, traditional drug susceptibility testing is still helpful for evaluation of such samples.

Early detection of multidrug- and pre-extensively drug-resistant tuberculosis from smear-positive sputum by direct sequencing

Background

Emergence of multidrug- and extensively drug-resistant tuberculosis (M/XDR-TB) is a major hurdle for TB control programs especially in developing countries like China. Resistance to fluoroquinolones is high among MDR-TB patients. Early diagnosis of MDR/pre-XDR-TB is essential for lowering transmission of drug-resistant TB and adjusting the treatment regimen.

Methods

Smear-positive sputum specimens (n = 186) were collected from Wuhan Institute for Tuberculosis Control. The DNA was extracted from the specimens and run through a Sanger sequencing assay to detect mutations associated with MDR/pre-XDR-TB including the rpoB core region for rifampicin (RIF) resistance; katG and inhA promoter for isoniazid (INH) resistance; and gyrA for fluoroquinolone (FQ) resistance. Sequencing data were compared to phenotypic Lowenstein-Jensen (L-J) proportion method drug susceptibility testing (DST) results for performance analysis.

Results

By comparing the mutation data with phenotypic results, the detection rates of MDR-TB and pre-XDR-TB were 84.31% (43/51) and 83.33% (20/24), respectively. The sequencing assay illustrated good sensitivity for the detection of resistance to RIF (96.92%), INH (86.89%), FQ (77.50%). The specificities of the assay were 98.35% for RIF, 99.20% for INH, and 97.26% for FQ.

Conclusions

The sequencing assay is an efficient, accurate method for detection of MDR-TB and pre-XDR-TB from clinical smear-positive sputum specimens, should be considered as a supplemental method for obtaining early DST results before the availability of phenotypic DST results. This could be of benefit to early diagnosis, adjusting the treatment regimen and controlling transmission of drug-resistant TB.

Pyrosequencing for rapid detection of Mycobacterium tuberculosis second-line drugs and ethambutol resistance

The aim of this work was to study the diagnostic accuracy of pyrosequencing to detect resistance to fluoroquinolones, kanamycin, amikacin, capreomycin, and ethambutol (EMB) in Mycobacterium tuberculosis clinical strains. One hundred four clinical isolates previously characterized by BACTEC 460TB/MGIT 960 were included. Specific mutations were targeted in gyrA, rrs, eis promoter, and embB. When there was a discordant result between BACTEC and pyrosequencing, Genotype MTBDRsl (Hain Lifescience, Nehren, Germany) was performed. Sensitivity and specificity of pyrosequencing were 70.6% and 100%, respectively, for fluoroquinolones; 93.3% and 81.7%, respectively, for kanamycin; 94.1% and 95.9%, respectively, for amikacin; 90.0% and 100%, respectively, for capreomycin; and 64.8% and 87.8%, respectively, for EMB. This study shows that pyrosequencing may be a useful tool for making early decisions regarding second-line drugs and EMB resistance. However, for a correct management of patients with suspected extensively drug-resistant tuberculosis, susceptibility results obtained by molecular methods should be confirmed by a phenotypic method.

Correlations between drug resistance of Beijing/W lineage clinical isolates of Mycobacterium tuberculosis and sublineages: a 2009-2013 prospective study in Xinjiang province, China

BACKGROUND

The prevalence of drug-resistant tuberculosis (TB) in Xinjiang is higher than in other regions of China, and Beijing/W lineage Mycobacterium tuberculosis (MTB) is the dominant strain of MTB in Xinjiang. However, information on multidrug-resistant (MDR) and extensively drug-resistant (XDR) TB, particularly the correlation between MDR and the Beijing/W lineage and the correlation between drug resistance and the Beijing/W sublineage strains, is limited.

MATERIAL/METHODS

We conducted a prospective study to describe the prevalence of MDR/XDR TB, Beijing/W lineage and sublineage strains in Xinjiang in China from 2009 to 2013. All MTB underwent drug susceptibility testing to the first- and second-line anti-tuberculosis drugs. The Beijing/W lineages and sublineages were detected by large-sequence polymorphisms with polymerase chain reaction.

RESULTS

A total of 410 clinical isolates were identified. The overall percentage of MDR and XDR cases in Xinjiang was 13.2% (54/410) and 13.0% (7/54), respectively. Overall, 9.8% (14/143) of the Beijing lineage MTB were MDR patients, and 15.6% (40/257) of the Non-Beijing lineage MTB were MDR patients. In the 143 Beijing MTB lineages, 11.2% isolates were in sublineage 105, 15.4% isolates were in sublineage 207, 69.2% isolates were in sublineage 181, and 4.2% isolates were in sublineage 150. None of the isolates were detected in sublineage 142. Significant differences between the Beijing/W and non-Beijing/W strains were observed regarding INH and EMB resistance, respectively.

CONCLUSIONS

The prevalence of the MDR TB in Xinjiang remains high and imposes challenges for TB control. Four Beijing/W sublineage isolates were observed in Xinjiang. There was no correlation between MDR and the Beijing/W lineage and no correlation between drug resistance and the Beijing/W sublineage strains. Surveillance of the clinical isolates of MTB is recommended to strengthen the identification of MDR/XDR TB and sublineages of the Beijing/W strains.