Analysis of Mycobacterium tuberculosis Genotypic Lineage Distribution in Chile and Neighboring Countries

Global epidemiology of Mycobacterium tuberculosis lineage 4 insights from Ecuadorian genomic data

Tuberculosis is a global public health concern, and understanding Mycobacterium tuberculosis transmission routes and genetic diversity of M. tuberculosis is crucial for outbreak control. This study aimed to explore the genomic epidemiology and genetic diversity of M. tuberculosis in Ecuador by analyzing 88 local isolates and 415 public genomes from 19 countries within the Euro-American lineage (L4). Our results revealed significant genomic diversity among the isolates, particularly in the genes related to protein processing, carbohydrate metabolism, lipid metabolism, and xenobiotic biodegradation and metabolism. The population structure analysis showed that sub-lineages 4.3.2/3 (35.4%), 4.1.2.1 (22.7%), 4.4.1 (12.7%), and 4.1.1. (10.7%) were the most prevalent. Phylogenetic and transmission network analyses suggest that these isolates circulating within Ecuador share genetic ties with isolates from other continents, implying historical and ongoing intercontinental transmission events. Our findings underscore the importance of integrating genomic data into public health strategies for tuberculosis control and suggest that enhanced genomic surveillance is essential for understanding and mitigating the global spread of M. tuberculosis. This study provides a comprehensive genomic framework for future epidemiological investigations and control measures targeting M. tuberculosis L4 in Ecuador.

Molecular epidemiology of Mycobacterium tuberculosis in Ecuador: Recent advances and future challenges

Tuberculosis (TB) is one of the three leading causes of death from a single infectious agent, Mycobacterium tuberculosis (MTB), together with COVID-19 and HIV/AIDS. This disease places a heavy burden on countries with low socio-economic development and aggravates existing inequalities. For the year 2021, estimations for Ecuador were 8500 TB cases, of which 370 were associated to multiple drug resistance (TB-MDR), and 1160 deaths. In the same year, Ecuador notified 5973 total cases, 401 of them were TB-MDR, pointing out an under diagnosis problem. The few molecular epidemiology studies available conclude that L4 is the most prevalent MTB lineage in Ecuador (with LAM as the main L4 sublineage), but L2-Beijing family is also present at low prevalence. Nevertheless, with less than 1 % MTB isolates genetically characterized by either MIRU-VNTR, spolygotyping or WGS to date, molecular epidemiology research must me improved to assist the TB surveillance and control program in Ecuador.

Population structure and spatial distribution of Mycobacterium tuberculosis in Ethiopia

Ethiopia is one of the countries with a high tuberculosis (TB) burden, yet little is known about the spatial distribution of Mycobacterium tuberculosis (Mtb) lineages. This study identifies the spoligotyping of 1735 archived Mtb isolates from the National Drug Resistance Survey, collected between November 2011 and June 2013, to investigate Mtb population structure and spatial distribution. Spoligotype International Types (SITs) and lineages were retrieved from online databases. The distribution of lineages was evaluated using Fisher's exact test and logistic regression models. The Global Moran's Index and Getis-Ord Gi statistic were utilized to identify hotspot areas. Our results showed that spoligotypes could be interpreted and led to 4 lineages and 283 spoligotype patterns in 91% of the isolates, including 4% of those with multidrug/rifampicin resistance (MDR/RR) TB. The identified Mtb lineages were lineage 1 (1.8%), lineage 3 (25.9%), lineage 4 (70.6%) and lineage 7 (1.6%). The proportion of lineages 3 and 4 varied by regions, with lineage 3 being significantly greater than lineage 4 in reports from Gambella (AOR = 4.37, P < 0.001) and Tigray (AOR = 3.44, P = 0.001) and lineage 4 being significantly higher in Southern Nations Nationalities and Peoples Region (AOR = 1.97, P = 0.026) than lineage 3. Hotspots for lineage 1 were located in eastern Ethiopia, while a lineage 7 hotspot was identified in northern and western Ethiopia. The five prevalent spoligotypes, which were SIT149, SIT53, SIT25, SIT37 and SIT26 account for 42.8% of all isolates under investigation, while SIT149, SIT53 and SIT21 account for 52-57.8% of drug-resistant TB cases. TB and drug resistant TB are mainly caused by lineages 3 and 4, and significant proportions of the prevalent spoligotypes also influence drug-resistant TB and the total TB burden. Regional variations in lineages may result from both local and cross-border spread.

Comparative genomics of drug-resistant strains of Mycobacterium tuberculosis in Ecuador

BACKGROUND

Tuberculosis is a serious infectious disease affecting millions of people. In spite of efforts to reduce the disease, increasing antibiotic resistance has contributed to persist in the top 10 causes of death worldwide. In fact, the increased cases of multi (MDR) and extreme drug resistance (XDR) worldwide remains the main challenge for tuberculosis control. Whole genome sequencing is a powerful tool for predicting drug resistance-related variants, studying lineages, tracking transmission, and defining outbreaks. This study presents the identification and characterization of resistant clinical isolates of Mycobacterium tuberculosis including a phylogenetic and molecular resistance profile study by sequencing the complete genome of 24 strains from different provinces of Ecuador.

RESULTS

Genomic sequencing was used to identify the variants causing resistance. A total of 15/21 isolates were identified as MDR, 4/21 as pre-XDR and 2/21 as XDR, with three isolates discarded due to low quality; the main sub-lineage was LAM (61.9%) and Haarlem (19%) but clades X, T and S were identified. Of the six pre-XDR and XDR strains, it is noteworthy that five come from females; four come from the LAM sub-lineage and two correspond to the X-class sub-lineage. A core genome of 3,750 genes, distributed in 295 subsystems, was determined. Among these, 64 proteins related to virulence and implicated in the pathogenicity of M. tuberculosis and 66 possible pharmacological targets stand out. Most variants result in nonsynonymous amino acid changes and the most frequent genotypes were identified as conferring resistance to rifampicin, isoniazid, ethambutol, para-aminosalicylic acid and streptomycin. However, an increase in the resistance to fluoroquinolones was detected.

CONCLUSION

This work shows for the first time the variability of circulating resistant strains between men and women in Ecuador, highlighting the usefulness of genomic sequencing for the identification of emerging resistance. In this regard, we found an increase in fluoroquinolone resistance. Further sampling effort is needed to determine the total variability and associations with the metadata obtained to generate better health policies.

Phylogenetic lineages of tuberculosis isolates and their association with patient demographics in Tanzania

BACKGROUND

Mycobacterium tuberculosis presents several lineages each with distinct characteristics of evolutionary status, transmissibility, drug resistance, host interaction, latency, and vaccine efficacy. Whole genome sequencing (WGS) has emerged as a new diagnostic tool to reliably inform the occurrence of phylogenetic lineages of Mycobacterium tuberculosis and examine their relationship with patient demographic characteristics and multidrug-resistance development.

METHODS

191 Mycobacterium tuberculosis isolates obtained from a 2017/2018 Tanzanian drug resistance survey were sequenced on the Illumina Miseq platform at Supranational Tuberculosis Reference Laboratory in Uganda. Obtained fast-q files were imported into tools for resistance profiling and lineage inference (Kvarq v0.12.2, Mykrobe v0.8.1 and TBprofiler v3.0.5). Additionally for phylogenetic tree construction, RaxML-NG v1.0.3(25) was used to generate a maximum likelihood phylogeny with 800 bootstrap replicates. The resulting trees were plotted, annotated and visualized using ggtree v2.0.4 RESULTS: Most [172(90.0%)] of the isolates were from newly treated Pulmonary TB patients. Coinfection with HIV was observed in 33(17.3%) TB patients. Of the 191 isolates, 22(11.5%) were resistant to one or more commonly used first line anti-TB drugs (FLD), 9(4.7%) isolates were MDR-TB while 3(1.6%) were resistant to all the drugs. Of the 24 isolates with any resistance conferring mutations, 13(54.2%) and 10(41.6%) had mutations in genes associated with resistance to INH and RIF respectively. The findings also show four major lineages i.e. Lineage 3[81 (42.4%)], followed by Lineage 4 [74 (38.7%)], the Lineage 1 [23 (12.0%)] and Lineages 2 [13 (6.8%)] circulaing in Tanzania.

CONCLUSION

The findings in this study show that Lineage 3 is the most prevalent lineage in Tanzania whereas drug resistant mutations were more frequent among isolates that belonged to Lineage 4.

The host-pathogen-environment triad: Lessons learned through the study of the multidrug-resistant Mycobacterium tuberculosis M strain

Multidrug-resistant tuberculosis is one of the major obstacles that face the tuberculosis eradication efforts. Drug-resistant Mycobacterium tuberculosis clones were initially disregarded as a public health threat, because they were assumed to have paid a high fitness cost in exchange of resistance acquisition. However, some genotypes manage to overcome the impact of drug-resistance conferring mutations, retain transmissibility and cause large outbreaks. In Argentina, the HIV-AIDS epidemics fuelled the expansion of the so-called M strain in the early 1990s, which is responsible for the largest recorded multidrug-resistant tuberculosis cluster of Latin America. The aim of this work is to review the knowledge gathered after nearly three decades of multidisciplinary research on epidemiological, microbiological and immunological aspects of this highly successful strain. Collectively, our results indicate that the successful transmission of the M strain could be ascribed to its unaltered virulence, low Th1/Th17 response, a low fitness cost imposed by the resistance conferring mutations and a high resistance to host-related stress. In the early 2000s, the incident cases due to the M strain steadily declined and stabilized in the latest years. Improvements in the management, diagnosis and treatment of multidrug-resistant tuberculosis along with societal factors such as the low domestic and international mobility of the patients affected by this strain probably contributed to the outbreak containment. This stresses the importance of sustaining the public health interventions to avoid the resurgence of this conspicuous multidrug-resistant strain.

Mycobacterium tuberculosis SIT42 Infection in an Abused Dog in Southern Italy

A case of Mycobacterium tuberculosis infection is described in a dead adult male dog in Southern Italy. The carcass was found by the Health Authority in a gypsy encampment. It was admitted to our forensic veterinary medicine unit, with a suspicion of cruelty to the animal. Necropsy showed beating and traumatism signs, and mistreating was confirmed. Gross lesions included multiple nodular hepatic lesions, hemorrhagic enteritis with enlarged mesenteric lymph nodes, body cavity effusions, and an adrenal neoplasm. Bacteriological and molecular analyses were carried out on the liver lesions that enabled to identify M. tuberculosis SIT42 (LAM9). Drug-resistance patterns were evaluated by screening mutations on the rpoB and katG genes that showed susceptibility to both rifampin and isoniazid, respectively. Very few studies report canine tuberculosis, and little is known about the disease in Italy. To the authors' knowledge, this is the first report of Mycobacterium tuberculosis SIT42 infection in a dog in Italy.

Whole genome analysis of extensively drug resistant Mycobacterium tuberculosis strains in Peru

Peru has the highest burden of multidrug-resistant tuberculosis in the Americas region. Since 1999, the annual number of extensively drug-resistant tuberculosis (XDR-TB) Peruvian cases has been increasing, becoming a public health challenge. The objective of this study was to perform genomic characterization of Mycobacterium tuberculosis strains obtained from Peruvian patients with XDR-TB diagnosed from 2011 to 2015 in Peru. Whole genome sequencing (WGS) was performed on 68 XDR-TB strains from different regions of Peru. 58 (85.3%) strains came from the most populated districts of Lima and Callao. Concerning the lineages, 62 (91.2%) strains belonged to the Euro-American Lineage, while the remaining 6 (8.8%) strains belonged to the East-Asian Lineage. Most strains (90%) had high-confidence resistance mutations according to pre-established WHO-confident grading system. Discordant results between microbiological and molecular methodologies were caused by mutations outside the hotspot regions analysed by commercial molecular assays (rpoB I491F and inhA S94A). Cluster analysis using a cut-off ≤ 10 SNPs revealed that only 23 (34%) strains evidenced recent transmission links. This study highlights the relevance and utility of WGS as a high-resolution approach to predict drug resistance, analyse transmission of strains between groups, and determine evolutionary patterns of circulating XDR-TB strains in the country.

Population structure and genetic diversity of Mycobacterium tuberculosis in Ecuador

Tuberculosis (TB) is a significant public health problem in Ecuador with an incidence of 43 per 100,000 inhabitants and an estimated multidrug-resistant-TB prevalence in all TB cases of 9%. Genotyping of Mycobacterium tuberculosis (MTBC) is important to understand regional transmission dynamics. This study aims to describe the main MTBC lineages and sublineages circulating in the country. A representative sample of 373 MTBC strains from 22 provinces of Ecuador, with data comprising geographic origin and drug susceptibility, were genotyped using 24 loci-MIRU-VNTR. For strains with an ambiguous sublineage designation, the lineage was confirmed by Regions of Difference analysis or by Whole Genome Sequencing. We show that lineage 4 is predominant in Ecuador (98.3% of the strains). Only 4 strains belong to lineages 2-sublineage Beijing and two strains to lineage 3-sublineage Delhi. Lineage 4 strains included sublineages LAM (45.7%), Haarlem (31.8%), S (13.1%), X (4.6%), Ghana (0.6%) and NEW (0.3%). The LAM sublineage showed the strongest association with antibiotic resistance. The X and S sublineages were found predominantly in the Coastal and the Andean regions respectively and the reason for the high prevalence of these strains in Ecuador should be addressed in future studies. Our database constitutes a tool for MIRU-VNTR pattern comparison of M. tuberculosis isolates for national and international epidemiologic studies and phylogenetic purposes.

Genetic Diversity and Molecular Epidemiology of Mycobacterium tuberculosis in Roraima State, Brazil

National border areas are special places for the spread of Mycobacterium tuberculosis (MTB). These regions concentrate vulnerable populations and constant population movements. Understanding the dynamics of the transmission of MTB is fundamental to propose control measures and to monitor drug resistance. We conducted a population-based prospective study of tuberculosis (TB) to evaluate molecular characteristics of MTB isolates circulating in Roraima, a state on the border of Venezuela and Guyana. Eighty isolates were genotyped by IS6110-RFLP (restriction fragment length polymorphism), spoligotyping, and 24-locus mycobacterial interspersed repetitive unit-variable number of repeats tandem (MIRU-VNTR). Drug susceptibility tests were performed by using the proportion method and GeneXpert^® MTB/RIF (Cepheid, Sunnyvale, CA). Isolates showing a phenotypic resistance profile were submitted to polymerase chain reaction (PCR) and sequencing. Spoligotyping showed 40 distinct patterns with a high prevalence of Latin-American and Mediterranean (LAM), Haarlem (H), and the "ill-defined" T clades. Mycobacterial interspersed repetitive unit -VNTR and IS6110-RFLP showed clustering rates of 21.3% and 30%, respectively. Drug resistance was detected in 11 (15.1%) isolates, and all were found to have primary resistance; among these, six (8.2%) isolates were streptomycin mono-resistant, four (5.4%) isoniazid mono-resistant, and one (1.3%) multidrug resistant. This is the first study on the molecular epidemiology and drug resistance profile of MTB from Roraima. Herein, we describe high diversity of genetic profiles circulating in this region that may be driven by the introduction of new strain types because of large population flow in this region. In summary, our results showed that analyses of these circulating strains can contribute to a better understanding of TB epidemiology in the northern Brazilian border and be useful to establish public health policies on TB prevention.

Circulation of M. tuberculosis Beijing genotype in Latin America and the Caribbean

Lineage 2 (East Asian), which includes the Beijing genotype, is one of the most prevalent lineages of Mycobacterium tuberculosis (Mtb) throughout the world. The Beijing family is associated to hypervirulence and drug-resistant tuberculosis. The study of this genotype's circulation in Latin America is crucial for achieving total control of TB, the goal established by the World Health Organization, for the American sub-continent, before 2035. In this sense, the present work presents an overview of the status of the Beijing genotype for this region, with a bibliographical review, and data analysis of MIRU-VNTRs for available Beijing isolates. Certain countries present a prevalent trend of <5%, suggesting low transmissibility for the region, with the exception of Cuba (17.2%), Perú (16%) and Colombia (5%). Minimum Spanning Tree analysis, obtained from MIRU-VNTR data, shows distribution of specific clonal complex strains in each country. From this data, in most countries, we found that molecular epidemiology has not been a tool used for the control of TB, suggesting that the Beijing genotype may be underestimated in Latin America. It is recommended that countries with the highest incidence of the Beijing genotype use effective control strategies and increased care, as a requirement for public health systems.

Discordance between the QuantiFERON Gold In-Tube and QuantiFERON Gold Plus assays associated with country of birth TB incidence

BACKGROUND

The new QuantiFERON Gold Plus (QFT+) assay is used for diagnosing tuberculosis (TB) infection and has 2 phlebotomy methods: direct (QFT + D) and single tube transfer (QFT + T). Little data is available on how the TB incidence in the country of birth (COB) of healthcare workers (HCWs) can impact the assay results.

METHODS

QuantiFERON Gold In-Tube (QFT-G), QFT + D and QFT + T assays were obtained from a single blood draw and compared for HCWs annually tested for TB infection. HCWs COB was ranked as: high (≥150 per 100,000), medium (20-149), and low TB incidence (<20 TB cases).

RESULTS

In 265 HCWs, QFT-G/+D/+T results from medium TB incidence COB (15.6%, 16.9% and 22.1%) were more likely to be positive than high (9.7%, 11.8% and 16.1%) or low incidence COB (6.3%, 8.4% and 10.5%). Agreement between assay results for high, medium and low TB incidence COB were: 95.7%, 83.1%, and 95.8% between QFT-G/QFT + D (p = 0.003), 91.4%, 88.3% and 95.8% between QFT-G/QFT + T (p = 0.187), and 91.4%, 76.6%, and 91.6% between QFT + D/QFT + T (p = 0.005).

CONCLUSION

Lower agreement and a higher proportion of positivity were found in QFT-G/+D/+T results in individuals from medium TB incidence COB. QFT + may be more sensitive than QFT-G in HCWs from medium TB incidence COB.

Genotypic diversity of Mycobacterium tuberculosis in Buenos Aires, Argentina

Buenos Aires is an overpopulated port city historically inhabited by people of European descent. Together with its broader metropolitan area, the city exhibits medium tuberculosis rates, and receives migrants, mainly from tuberculosis highly endemic areas of Argentina and neighboring countries. This work was aimed to gain insight into the Mycobacterium tuberculosis population structure in two suburban districts of Buenos Aires which are illustrative of the overall situation of tuberculosis in Argentina. The Lineage 4 Euro-American accounted for >99% of the 816 isolates analyzed (one per patient). Frequencies of spoligotype families were T 35.9%, LAM 33.2%, Haarlem 19.5%, S 3.2%, X 1.5%, Ural 0.7%, BOV 0.2%, Beijing 0.2%, and Cameroon 0.2%. Unknown signatures accounted for 5.3% isolates. Of 55 spoligotypes not matching any extant shared international type (SIT) in SITVIT database, 22 fitted into 15 newly-issued SITs. Certain autochthonous South American genotypes were found to be actively evolving. LAM3, which is wild type for RD^rio, was the predominant LAM subfamily in both districts and the RD^rio signature was rare among autochthonous, newly created, SITs and orphan patterns. Two genotypes that are rarely observed in neighboring countries ̶ SIT2/H2 and SIT159/T1 Tuscany ̶ were conspicuously represented in Argentina. The infrequent Beijing patterns belonged to Peruvian patients. We conclude that the genotype diversity observed reflects the influence of the Hispanic colonization and more recent immigration waves from Mediterranean and neighboring countries. Unlike in Brazil, the RD^rio type does not play a major role in the tuberculosis epidemic in Buenos Aires.

[Identification of the Mycobacterium tuberculosis Beijing lineage in Ecuador]

INTRODUCTION

Mycobacterium tuberculosis Beijing lineage isolates are considered to be especially virulent, transmissible and prone to acquire resistances. Beijing strains have been reported worldwide, but studies in Latin America are still scarce. The only multinational study performed in the region indicated a heterogeneous distribution for this lineage, which was absent in Chile, Colombia and Ecuador, although further studies found the lineage in Chile and Colombia.

OBJECTIVE

To search for the presence of the Beijing lineage in Ecuador, the only country in the region where it remains unreported.

MATERIALS AND METHODS

We obtained a convenience sample (2006-2012) from two hospitals covering different populations. The isolates were genotyped using 24-MIRU-VNTR. Lineages were assigned by comparing their patterns to those in the MIRU-VNTRplus platform. Isolates belonging to the Beijing lineage were confirmed by allele-specific PCR.

RESULTS

We identified the first Beijing isolate in Ecuador in an unexpected epidemiological scenario: A patient was infected in the Andean region, in a population with low mobility and far from the borders of the neighboring countries where Beijing strains had been previously reported.

CONCLUSION

This is the first report of the presence of the Beijing lineage in Ecuador in an unusual epidemiological context that deserves special attention.