Genomic signatures of drug resistance in highly resistant Mycobacterium tuberculosis strains of the early ancient sublineage of Beijing genotype in Russia

Insight into pathogenomics and phylogeography of hypervirulent and highly-lethal Mycobacterium tuberculosis strain cluster

BACKGROUND

. The Mycobacterium tuberculosis Beijing genotype is globally spread lineage with important medical properties that however vary among its subtypes. M. tuberculosis Beijing 14717-15-cluster was recently discovered as both multidrug-resistant, hypervirulent, and highly-lethal strain circulating in the Far Eastern region of Russia. Here, we aimed to analyze its pathogenomic features and phylogeographic pattern.

RESULTS

. The study collection included M. tuberculosis DNA collected between 1996 and 2020 in different world regions. The bacterial DNA was subjected to genotyping and whole genome sequencing followed by bioinformatics and phylogenetic analysis. The PCR-based assay to detect specific SNPs of the Beijing 14717-15-cluster was developed and used for its screening in the global collections. Phylogenomic and phylogeographic analysis confirmed endemic prevalence of the Beijing 14717-15-cluster in the Asian part of Russia, and distant common ancestor with isolates from Korea (> 115 SNPs). The Beijing 14717-15-cluster isolates had two common resistance mutations RpsL Lys88Arg and KatG Ser315Thr and belonged to spoligotype SIT269. The Russian isolates of this cluster were from the Asian Russia while 4 isolates were from the Netherlands and Spain. The cluster-specific SNPs that significantly affect the protein function were identified in silico in genes within different categories (lipid metabolism, regulatory proteins, intermediary metabolism and respiration, PE/PPE, cell wall and cell processes).

CONCLUSIONS

. We developed a simple method based on real-time PCR to detect clinically significant MDR and hypervirulent Beijing 14717-15-cluster. Most of the identified cluster-specific mutations were previously unreported and could potentially be associated with increased pathogenic properties of this hypervirulent M. tuberculosis strain. Further experimental study to assess the pathobiological role of these mutations is warranted.

Molecular detection and phylogeography of the hypervirulent subtype of Mycobacterium tuberculosis Beijing 14717-15

Aim. To develop a method for the detection of Mycobacterium tuberculosis strains of the highly lethal, hypervirulent, and multidrug-resistant Beijing 14717-15-cluster and its application for screening retrospective collections of M. tuberculosis from regions of Russia. The collection included M. tuberculosis DNA samples collected within population studies. Spoligotyping and genotyping of 24 variable number of tandem repeats loci were performed according to standard protocols. Phylogenetic analysis was based on the whole genome sequencing data. Polymorphism at the genomic position 2423040 AG, specific for the Beijing 14717-15 cluster, was detected using PCR-RFLP and HhaI restriction enzyme. The bioinformatic and phylogenetic analysis of whole genome sequencing data of 205 strains of the early ancient sublineage of the M. tuberculosis Beijing genotype showed that strains with the VNTR 14717-15 profile (according to MIRU-VNTRplus.org) and those close to it were grouped into one monophyletic cluster of related strains, which we defined as Beijing 14717-15-cluster. Among the SNPs specific for the 14717-15 cluster, we chose a functionally neutral SNP at the genomic position 2423040 AG (Rv2161c Val33Ala) and developed a method for its detection in the PCR-RFLP format. Next, we applied this method to screening DNA collections from the regions of the European and Asian parts of Russia and Asian countries. The results demonstrate the presence of strains of the Beijing 14717-15 cluster only in the Asian part of Russia, with a peak in Buryatia (18%). We have developed a method for the detection of the hypervirulent and highly lethal genetic cluster M. tuberculosis Beijing 14717-15 based on the detection of a specific mutation in the Rv2161c gene using PCR followed by HhaI restriction of the PCR product and agarose gel electrophoresis to discriminate between wild-type and mutant alleles. The advantages of the proposed method are the speed, simple and unambiguous interpretation of the results, the ability to detect contamination and mixed infection, suitability for efficient analysis of large collections of M. tuberculosis strains.

Molecular characteristics of Mycobacterium tuberculosis drug-resistant isolates from HIV- and HIV+ tuberculosis patients in Russia

Background

High burden of drug-resistant (DR) tuberculosis (TB) is a significant threat to national TB control programs all over the world and in the Russian Federation. Different Mycobacterium tuberculosis (MTB) genotypes are hypothesized to have specific characteristics affecting TB control programs. For example, Beijing strains are supposed to have higher mutation rates compared to strains of other genotypes and subsequently higher capability to develop drug-resistance.

Results

Clinical MTB isolates from HIV- and HIV+ patients from four regions of Russia were analyzed for genotypes and mutations conferring resistance to Isoniazid, Rifampicin, Ethambutol, aminoglycosides, and fluoroquinolones. Analysis of genotypes and polymorphism of genomic loci according to the HIV status of the patients – sources of MTB isolates were performed. Studied MTB isolates from HIV- TB patients belonged to 15 genotypes and from HIV + TB patients – to 6 genotypes. Beijing clinical isolates dominated in HIV- (64,7%) and HIV+ (74,4%) groups. Other isolates were of LAM (including LAM1 and LAM9), Ural, and 4 minor groups of genotypes (including 5 subclones T). The spectrum of genotypes in the HIV- group was broader than in the HIV+ group. PR of B0/W148 Beijing was significantly lower than of other Beijing genotypes in susceptible and MDR-XDR isolates. Rates of isolates belonging to non-Beijing genotypes were higher than Beijing in susceptible isolates from HIV- patients.

Conclusions

Beijing genotype isolates prevailed in clinical isolates of all drug susceptibility profiles both from HIV- and HIV+ patients, although B0/W148 Beijing genotype did not dominate in this study. Genome loci and mutations polymorphisms were more pronounced in clinical isolates from HIV- patients, than from HIV+.

Impact of pathobiological diversity of Mycobacterium tuberculosis on clinical features and lethal outcome of tuberculosis

BACKGROUND

Mycobacterium tuberculosis population in Russia is dominated by the notorious Beijing genotype whose major variants are characterized by contrasting resistance and virulence properties. Here we studied how these strain features could impact the progression of pulmonary tuberculosis (TB) concerning clinical manifestation and lethal outcome.

RESULTS

The study sample included 548 M. tuberculosis isolates from 548 patients with newly diagnosed pulmonary TB in Omsk, West Siberia, Russia. Strains were subjected to drug susceptibility testing and genotyping to detect lineages, sublineages, and subtypes (within Beijing genotype). The Beijing genotype was detected in 370 (67.5%) of the studied strains. The strongest association with multidrug resistance (MDR) was found for epidemic cluster Beijing B0/W148 (modern sublineage) and two recently discovered MDR clusters 1071-32 and 14717-15 of the ancient Beijing sublineage. The group of patients infected with hypervirulent and highly lethal (in a mouse model) Beijing 14717-15 showed the highest rate of lethal outcome (58.3%) compared to Beijing B0/W148 (31.4%; P = 0.06), Beijing Central Asian/Russian (29.7%, P = 0.037), and non-Beijing (15.2%, P = 0.001). The 14717-15 cluster mostly included isolates from patients with infiltrative but not with fibrous-cavernous and disseminated TB. In contrast, a group infected with low virulent 1071-32-cluster had the highest rate of fibrous-cavernous TB, possibly reflecting the capacity of these strains for prolonged survival and chronicity of the TB process.

CONCLUSIONS

The group of patients infected with hypervirulent and highly lethal in murine model 14717-15 cluster had the highest proportion of the lethal outcome (58.3%) compared to the groups infected with Beijing B0/W148 (31.4%) and non-Beijing (15.2%) isolates. This study carried out in the TB high-burden area highlights that not only drug resistance but also strain virulence should be considered in the implementation of personalized TB treatment.

Revised nomenclature and SNP barcode for Mycobacterium tuberculosis lineage 2

Mycobacterium tuberculosis (Mtb) lineage 2 (L2) strains are present globally, contributing to a widespread tuberculosis (TB) burden, particularly in Asia where both prevalence of TB and numbers of drug resistant TB are highest. The increasing availability of whole-genome sequencing (WGS) data worldwide provides an opportunity to improve our understanding of the global genetic diversity of Mtb L2 and its association with the disease epidemiology and pathogenesis. However, existing L2 sublineage classification schemes leave >20 % of the Modern Beijing isolates unclassified. Here, we present a revised SNP-based classification scheme of L2 in a genomic framework based on phylogenetic analysis of >4000 L2 isolates from 34 countries in Asia, Eastern Europe, Oceania and Africa. Our scheme consists of over 30 genotypes, many of which have not been described before. In particular, we propose six main genotypes of Modern Beijing strains, denoted L2.2.M1–L2.2.M6. We also provide SNP markers for genotyping L2 strains from WGS data. This fine-scale genotyping scheme, which can classify >98 % of the studied isolates, serves as a basis for more effective monitoring and reporting of transmission and outbreaks, as well as improving genotype-phenotype associations such as disease severity and drug resistance. This article contains data hosted by Microreact.

Practical approach to detection and surveillance of emerging highly resistant Mycobacterium tuberculosis Beijing 1071-32-cluster

Ancient sublineage of the Mycobacterium tuberculosis Beijing genotype is endemic and prevalent in East Asia and rare in other world regions. While these strains are mainly drug susceptible, we recently identified a novel clonal group Beijing 1071-32 within this sublineage emerging in Siberia, Russia and present in other Russian regions. This cluster included only multi/extensive drug resistant (MDR/XDR) isolates. Based on the phylogenetic analysis of the available WGS data, we identified three synonymous SNPs in the genes Rv0144, Rv0373c, and Rv0334 that were specific for the Beijing 1071-32-cluster and developed a real-time PCR assay for their detection. Analysis of the 2375 genetically diverse M. tuberculosis isolates collected between 1996 and 2020 in different locations (European and Asian parts of Russia, former Soviet Union countries, Albania, Greece, China, Vietnam, Japan and Brazil), confirmed 100% specificity and sensitivity of this real-time PCR assay. Moreover, the epidemiological importance of this strain and the newly developed screening assay is further stressed by the fact that all identified Beijing 1071-32 isolates were found to exhibit MDR genotypic profiles with concomitant resistance to additional first-line drugs due to a characteristic signature of six mutations in rpoB450, rpoC485, katG315, katG335, rpsL43 and embB497. In conclusion, this study provides a set of three concordant SNPs for the detection and screening of Beijing 1071-32 isolates along with a validated real-time PCR assay easily deployable across multiple settings for the epidemiological tracking of this significant MDR cluster.

Extremely lethal and hypervirulent Mycobacterium tuberculosis strain cluster emerging in Far East, Russia

Mycobacterium tuberculosis strains of the early ancient sublineage of the Beijing genotype are mostly drug susceptible and mainly circulate in East Asia. We have recently discovered two clusters of this sublineage emerging in the Asian part of Russia (VNTR-defined 1071-32 and 14717-15 types) and, to our surprise, both were strongly MDR/XDR-associated. Here, we evaluated their pathogenic features. The clinical isolates and reference laboratory strain H37Rv were investigated in the C57BL/6 mouse model to assess their virulence and lethality properties. The BACTEC MGIT 960 system was used to study the in vitro growth characteristics. In the murine model, strains 396 (14717-15-cluster, from Buryatia, Far East) and 6691 (1071-32-cluster, from Omsk, Siberia) demonstrated contrasting properties. The 396-infected group had significantly higher mortality, more weight loss, higher bacterial burden, and more severe lung pathology. Furthermore, compared to the previously published data on other Russian epidemic Beijing strains (B0/W148, CAO, Central Asian Russian), strain 396 demonstrated the highest mortality. Under the in vitro growth experiment, cluster 14717-15 isolates had significantly shorter lag-phase. To conclude, low-virulent MDR strain 6691 belongs to the Beijing 1071-32-cluster widespread across FSU countries but at low prevalence. This corresponds to common expectation that multiple drug resistance mutations reduce fitness and virulence. In contrast, highly lethal and hypervirulent MDR strain 396 represents an intriguing Beijing 14717-15 cluster predominant only in Buryatia, Far East (16%), sporadically found beyond it, but not forming clusters of transmission. Further in-depth study of this most virulent Russian Beijing cluster is warranted.

Drug-sensitivity test and analysis of drug-resistant mutations in Mycobacterium tuberculosis isolates from Kashgar, China

Introduction

In recent years, drug-resistant Mycobacterium tuberculosis strains have gradually become widespread. Most drug resistance is related to specific mutations. We investigated M. tuberculosis drug resistance in the Kashgar area, China.

Methods

The drug-susceptibility test was conducted to clinical isolates of M. tuberculosis. Genomic-sequencing technology was used for the drug-resistant strains and the significance of DNA sequencing as a rapid aid for drug-resistance detection and the diagnosis method was evaluated.

Results

The resistance rates of clinical isolates to rifampicin (RFP), isoniazid (INH), streptomycin (SM), ethambutol (EMB), and ofloxacin (OFX) were, respectively, 4.4%, 12.3%, 8.8%, 2.6%, and 3.5%. The single- and multi-drug resistance rates were, respectively, 80.0% and 20.0%. The resistance genes RopB, katG, InhA, RpsL, rrs, gyrA, and embB displayed codon mutations, while InhA was mutated in its promoter region. Kappa scores, evaluating the consistency between DNA sequencing and the resistance ratio methods for the detection of isolates’ resistance to RFP, INH, SM, OFX, and EMB, were 1, 0.955, 0.721, 0.796, and 1, respectively.

Conclusion

The resistance rate of INH and SM is relatively high in the Kashgar area. Detection of mutations in RopB, katG, InhA, RpsL, rrs, gyrA, and embB by DNA sequencing can predict drug resistance of M. tuberculosis strains with high sensitivity and specificity, and can be used for diagnosis.