Molecular epidemiology of multi- and extensively-drug-resistant Mycobacterium tuberculosis in Ireland, 2001-2014

Tuberculosis in Poland: Epidemiological and Molecular Analysis during the COVID-19 Pandemic

The COVID-19 pandemic may have a negative impact on the proper implementation of TB control programmes and may increase TB incidence rates in the near future. The aim of this study was to perform an epidemiological and molecular analysis of Mycobacterium tuberculosis strains cultured from tuberculosis patients in Poland in 2020 and to compare the results of monitoring drug-resistant tuberculosis in Poland with previous studies in 2012 and 2016. The analysis was based on questionnaires and strains sent by regional laboratories during the 12 months of 2020. Molecular analysis was performed by spoligotyping 20% of the strains sensitive to the four primary antimycobacterial drugs and all of the drug-resistant strains. The number of strains sent for analysis dropped threefold, from 4136 in 2012 to 1383 in 2020. The incidence of tuberculosis among men was higher than among women. There was an increase in strains’ resistance to antimycobacterial drugs in both newly diagnosed patients, from 4.4% in 2012 to 6.1% in 2020, and previously treated patients, from 11.7% to 12.3%. Four-year resistance increased to 1% and 2.1%, respectively. The spoligotype SIT1 was the most abundant among the resistant strains (17%), and SIT53 (13.9%) was the most common among susceptible strains.

Transmission, distribution and drug resistance-conferring mutations of extensively drug-resistant tuberculosis in the Western Cape Province, South Africa

Extensively drug-resistant tuberculosis (XDR-TB), defined as resistance to at least isoniazid (INH), rifampicin (RIF), a fluoroquinolone (FQ) and a second-line injectable drug (SLID), is difficult to treat and poses a major threat to TB control. The transmission dynamics and distribution of XDR Mycobacterium tuberculosis (Mtb) strains have not been thoroughly investigated. Using whole genome sequencing data on 461 XDR-Mtb strains, we aimed to investigate the geographical distribution of XDR-Mtb strains in the Western Cape Province of South Africa over a 10 year period (2006–2017) and assess the association between Mtb sub-lineage, age, gender, geographical patient location and membership or size of XDR-TB clusters. First, we identified transmission clusters by excluding drug resistance-conferring mutations and using the 5 SNP cutoff, followed by merging clusters based on their most recent common ancestor. We then consecutively included variants conferring resistance to INH, RIF, ethambutol (EMB), pyrazinamide (PZA), SLIDs and FQs in the cluster definition. Cluster sizes were classified as small (2–4 isolates), medium (5–20 isolates), large (21–100 isolates) or very large (>100 isolates) to reflect the success of individual strains. We found that most XDR-TB strains were clustered and that including variants conferring resistance to INH, RIF, EMB, PZA and SLIDs in the cluster definition did not significantly reduce the proportion of clustered isolates (85.5–82.2 %) but increased the number of patients belonging to small clusters (4.3–12.4 %, P=0.56). Inclusion of FQ resistance-conferring variants had the greatest effect, with 11 clustered isolates reclassified as unique while the number of clusters increased from 17 to 37. Lineage 2 strains (lineage 2.2.1 typical Beijing or lineage 2.2.2 atypical Beijing) showed the large clusters which were spread across all health districts of the Western Cape Province. We identified a significant association between residence in the Cape Town metropole and cluster membership (P=0.016) but no association between gender, age and cluster membership or cluster size (P=0.39). Our data suggest that the XDR-TB epidemic in South Africa probably has its origin in the endemic spread of MDR Mtb and pre-XDR Mtb strains followed by acquisition of FQ resistance, with more limited transmission of XDR Mtb strains. This only became apparent with the inclusion of drug resistance-conferring variants in the definition of a cluster. In addition to the prevention of amplification of resistance, rapid diagnosis of MDR, pre-XDR and XDR-TB and timely initiation of appropriate treatment is needed to reduce transmission of difficult-to-treat TB.

Beijing genotype of Mycobacterium tuberculosis is associated with extensively drug-resistant tuberculosis: A global analysis

We found that the frequency of Beijing genotype among XDR-TB strains was high. The data in this study would help guide the TB control program, and we however need further investigation to confirm the reliability of the present findings.

Reporting practices for genomic epidemiology of tuberculosis: a systematic review of the literature using STROME-ID guidelines as a benchmark

BACKGROUND

Pathogen genomics have become increasingly important in infectious disease epidemiology and public health. The Strengthening the Reporting of Molecular Epidemiology for Infectious Diseases (STROME-ID) guidelines were developed to outline a minimum set of criteria that should be reported in genomic epidemiology studies to facilitate assessment of study quality. We evaluate such reporting practices, using tuberculosis as an example.

METHODS

For this systematic review, we initially searched MEDLINE, Embase Classic, and Embase on May 3, 2017, using the search terms "tuberculosis" and "genom* sequencing". We updated this initial search on April 23, 2019, and also included a search of bioRxiv at this time. We included studies in English, French, or Spanish that recruited patients with microbiologically confirmed tuberculosis and used whole genome sequencing for typing of strains. Non-human studies, conference abstracts, and literature reviews were excluded. For each included study, the number and proportion of fulfilled STROME-ID criteria were recorded by two reviewers. A comparison of the mean proportion of fulfilled STROME-ID criteria before and after publication of the STROME-ID guidelines (in 2014) was done using a two-tailed t test. Quasi-Poisson regression and tobit regression were used to examine associations between study characteristics and the number and proportion of fulfilled STROME-ID criteria. This study was registered with PROSPERO, CRD42017064395.

FINDINGS

976 titles and abstracts were identified by our primary search, with an additional 16 studies identified in bioRxiv. 114 full texts (published between 2009 and 2019) were eligible for inclusion. The mean proportion of STROME-ID criteria fulfilled was 50% (SD 12; range 16-75). The proportion of criteria fulfilled was similar before and after STROME-ID publication (51% [SD 11] vs 46% [14], p=0·26). The number of criteria reported (among those applicable to all studies) was not associated with impact factor, h-index, country of affiliation of senior author, or sample size of isolates. Similarly, the proportion of criteria fulfilled was not associated with these characteristics, with the exception of a sample size of isolates of 277 or more (the highest quartile). In terms of reproducibility, 100 (88%) studies reported which bioinformatic tools were used, but only 33 (33%) reported corresponding version numbers. Sequencing data were available for 86 (75%) studies.

INTERPRETATION

The reporting of STROME-ID criteria in genomic epidemiology studies of tuberculosis between 2009 and 2019 was low, with implications for assessment of study quality. The considerable proportion of studies without bioinformatics version numbers or sequencing data available highlights a key concern for reproducibility.

Examining the levels of acetylation, DNA methylation and phosphorylation in HIV-1 positive and multidrug-resistant TB-HIV patients

OBJECTIVES

In this study, we examined the impact of epigenetic modifications on host gene functioning by assessing the expression of seven candidate genes in three separate groups including healthy, multidrug-resistant (MDR) TB-HIV co-infected and HIV-1 positive individuals.

METHODS

Ten patients with MDR TB and HIV-1 co-infection on TB and HIV therapy and a cohort comprised of 10 newly diagnosed individuals with HIV-1 infection were recruited from the TB and HIV clinics at the Charlotte Maxeke Johannesburg Academic Hospital. Notably, the HIV-1 positive individuals were not placed on antiretroviral therapy (ART) at the time of recruitment and blood collection. A third group consisting of 10 healthy participants without MDR TB or HIV infection was recruited from the University of the Witwatersrand. Blood samples collected from all three cohorts were employed for extraction of plasma, total RNA and genomic DNA.

RESULTS

Our data indicated that the expression of DNA methyltransferase 1 (DNMT1) and Ten-eleven translocation methylcytosine dioxygenase 1 (TET1) genes was significantly increased in HIV-1 positive patients and was lowest in MDR TB-HIV co-infected patients. By contrast, histone acetyltransferase (HAT), histone deacetylase (HDAC), protein tyrosine kinase (PtkA) and protein tyrosine phosphatase (PtpA) mRNA expression levels were substantially enhanced in HIV-1 infected and were lowest in healthy individuals. Conversely, Dicer expression levels were comparable among all three study groups.

CONCLUSION

Promising preliminary data emanating from this investigation may potentially be used for generation of novel vaccines and therapeutic compounds capable of neutralising MDR TB-HIV and HIV-1 infection.

Draft Genome Sequence of an Isolate of Extensively Drug-Resistant Mycobacterium tuberculosis from Nepal

Extensively drug-resistant (XDR) Mycobacterium tuberculosis has become a challenge to the treatment of tuberculosis (TB) in several countries, including Nepal. Here, we report for the first time the draft genome sequence of an isolate of XDR-TB collected in Nepal and describe single-nucleotide variations associated with its extensively drug-resistant phenotype.

Extensively drug-resistant (XDR) Mycobacterium tuberculosis has become a challenge to the treatment of tuberculosis (TB) in several countries, including Nepal. Here, we report for the first time the draft genome sequence of an isolate of XDR-TB collected in Nepal and describe single-nucleotide variations associated with its extensively drug-resistant phenotype.

[Multidrug-resistant tuberculosis: A management problem that weighs heavily on the University Hospitals of Strasbourg]

INTRODUCTION

Multidrug-resistant tuberculosis (MDR-TB) is a major public health problem with great regional disparities. The aim of this study was to describe the epidemiological, clinical, and therapeutics aspects of MDR-TB in Alsace, France.

PATIENTS AND METHODS

A 10 years retrospective study, conducted for the years 2006 to 2016, of all MDR-TB cases diagnosed in Alsace and particularly in Strasbourg University Hospitals.

RESULTS

We included 22 patients with MDR-TB of whom 90% originated from Eastern Europe, 13.6% had extensively-resistant strains, and 41% reported previously treated tuberculosis. Clinically, 86,4% had a pulmonary form of tuberculosis. The mean length of antibiotic treatment was 21 months with several changes of drugs because of severe side effects. The mean follow-up was 48 months, during which time 2 patients were lost from contact and the 20 remaining patients were cured.

CONCLUSIONS

Management of MDR-TB is a real social and medical challenge. Our study shows that the therapeutic protocols used in the management of these patients lead to an unusually high rate of success despite the occurrence of several, sometimes severe, side effects.

A nationwide study of multidrug-resistant tuberculosis in Portugal 2014-2017 using epidemiological and molecular clustering analyses

Background

Increasing multidrug-resistant tuberculosis (MDR-TB) incidence is a major threat against TB eradication worldwide. We aim to conduct a detailed MDR-TB study in Portugal, an European country with endemic TB, combining genetic analysis and epidemiological data, in order to assess the efficiency of public health containment of MRD-TB in the country.

Methods

We used published MIRU-VNTR data, that we reanalysed using a phylogenetic analysis to better describe MDR-TB cases transmission occurring in Portugal from 2014 to 2017, further enriched with epidemiological data of these cases.

Results

We show an MDR-TB transmission scenario, where MDR strains likely arose and are transmitted within local chains. 63% of strains were clustered, suggesting high primary transmission (estimated as 50% using MIRU-VNTR data and 15% considering epidemiological links). These values are higher than those observed across Europe and even for sensitive strains in Portugal using similar methodologies. MDR-TB cases are associated with individuals born in Portugal and evolutionary analysis suggests a local evolution of strains. Consistently the sublineage LAM, the most common in sensitive strains in Europe, is the more frequent in Portugal in contrast with the remaining European MDR-TB picture where immigrant-associated Beijing strains are more common.

Conclusions

Despite efforts to track and contain MDR-TB strains in Portugal, their transmission patterns are still as uncontrolled as that of sensitive strains, stressing the need to reinforce surveillance and containment strategies.

Electronic supplementary material

The online version of this article (10.1186/s12879-019-4189-7) contains supplementary material, which is available to authorized users.

Mycobacterial genomics and structural bioinformatics: opportunities and challenges in drug discovery

Of the more than 190 distinct species of Mycobacterium genus, many are economically and clinically important pathogens of humans or animals. Among those mycobacteria that infect humans, three species namely Mycobacterium tuberculosis (causative agent of tuberculosis), Mycobacterium leprae (causative agent of leprosy) and Mycobacterium abscessus (causative agent of chronic pulmonary infections) pose concern to global public health. Although antibiotics have been successfully developed to combat each of these, the emergence of drug-resistant strains is an increasing challenge for treatment and drug discovery. Here we describe the impact of the rapid expansion of genome sequencing and genome/pathway annotations that have greatly improved the progress of structure-guided drug discovery. We focus on the applications of comparative genomics, metabolomics, evolutionary bioinformatics and structural proteomics to identify potential drug targets. The opportunities and challenges for the design of drugs for M. tuberculosis, M. leprae and M. abscessus to combat resistance are discussed.