Repetitive Unit-variable Number Tandem Repeat Research Articles

Effect of mixed Mycobacterium tuberculosis infection on rapid molecular diagnostics among patients starting MDR-TB treatment in Uganda

BackgroundMixed M. tuberculosis (MTB) infection occurs when one is infected with more than one clonally distinct MTB strain. This form of infection can assist MTB strains to acquire additional mutations, facilitate the spread of drug-resistant strains, and boost the rate of treatment failure. Hence, the presence of mixed MTB infection could affect the performance of some rapid molecular diagnostic tests such as Line Probe Assay (LPA) and GeneXpert MTB/RIF (Xpert) assays.MethodsThis was a cross-sectional study that used sputum specimens collected from participants screened for STREAM 2 clinical trial between October 2017 and October 2019. Samples from 62 MTB smear-positive patients and rifampicin-resistant patients from peripheral health facilities were processed for Xpert and LPA as screening tests for eligibility in the trial. From November 2020, processed stored sputum samples were retrieved and genotyped to determine the presence of mixed-MTB strain infection using a standard 24-locus Mycobacterial Interspersed Repetitive Unit–Variable Number Tandem-Repeat (MIRU-VNTR). Samples with at least 20/24 MIRU-VNTR loci amplified were considered for analysis. Agar proportional Drug Susceptibility Test (DST) was performed on culture isolates of samples that had discordant results between LPA and Xpert. The impact of the presence of mixed-MTB strain on Xpert and LPA test interpretation was analyzed.ResultsA total of 53/62 (85%) samples had analyzable results from MIRU-VNTR. The overall prevalence of mixed-MTB infection was 5/53 (9.4%). The prevalence was highest among male’s 3/31 (9.7%) and among middle-aged adults, 4/30 (33.3%). Lineage 4 of MTB contributed 3/5 (60.0%) of the mixed-MTB infection prevalence. Having mixed MTB strain infection increased the odds of false susceptible Xpert test results (OR 7.556, 95% CI 0.88–64.44) but not for LPA. Being HIV-positive (P = 0.04) independently predicted the presence of mixed MTB infection.ConclusionsThe presence of mixed-MTB strain infection may affect the performance of the GeneXpert test but not for LPA. For patients with high pre-test probability of rifampicin resistance, an alternative rapid method such as LPA should be considered.

Molecular epidemiology and drug resistance of Mycobacterium tuberculosis in a tertiary care hospital in northeastern Mexico.

Tuberculosis (TB) is a re-emerging disease considered a public health concern. In the present study, we analyzed the epidemiology and drug resistance of Mycobacterium tuberculosis strains isolated from patients with pulmonary TB. Mycobacterium tuberculosis isolates (n = 190) were obtained from patients with pulmonary TB admitted to Dr. José Eleuterio González University Hospital (UH). Each M. tuberculosis isolate was analyzed by spoligotyping (spacer oligonucleotide typing) and MIRU-VNTR (Mycobacterial Interspersed Repetitive Units-Variable Number Tandem Repeat). Drug resistance was evaluated using the Anyplex™ II MTB/MDR/XDR assay. The predominant spoligotypes observed were X1 (SIT 119, n = 46), T1 (SIT 53, n = 40), H3 (SIT 50, n = 13), Beijing (SIT 1, n = 11), and EAI2-Manila (SIT 19, n = 8). MIRU-VNTR analysis showed that the locus QUB-26 had the highest allelic variability. The observed drug resistance included monoresistance to rifampicin (2.6%; n = 5), isoniazid (3.2%; n = 6), and fluoroquinolones (1.6%; n = 3) as well as multidrug resistance (5.3%; n = 10). All of the Beijing strains were susceptible. Regarding comorbidities, 13.7% (26/190) of the patients were co-infected with TB and HIV (TB+HIV+), and 31.6% (55/190) had TB along with diabetes (TB + diabetes). The most prevalent lineages were X1 (SIT 119; 24.3%) and T1 (SIT 53; 21%). An alarming proportion (12.6%) of M. tuberculosis isolates presented drug resistance. To effectively manage TB, continuous surveillance of regional strain dissemination, drug resistance profiles, and TB-associated comorbidities is crucial.

Molecular epidemiology and drug sensitivity of Mycobacterium tuberculosis in homeless individuals in the Addis Ababa city, Ethiopia

Although homeless segment of the society could be the hotspots for tuberculosis (TB) transmission, there is little data on TB in homeless individuals in Ethiopia. The objective of this study was to investigate the molecular epidemiology and drug sensitivity of Mycobacterium tuberculosis (M. tuberculosis) isolated from homeless individuals in Addis Ababa, Ethiopia. The study was conducted on 59 M. tuberculosis isolates, which were recovered by the clinical screening of 5600 homeless individuals and bacteriological examination of 641 individuals with symptoms of pulmonary tuberculosis (PTB). Region of difference-9 (RD9) based polymerase-chain reaction (PCR), Spoligotyping and 24-loci Mycobacterial Interspersed Repetitive Unit-Variable Number Tandem Repeat (MIRU-VNTR) typing were used for genotyping of the isolates. In addition, drug sensitivity test was performed on the isolates using BD Bactec Mycobacterial Growth Inhibition Tube (MGIT) 960. Fifty-eight of the 59 isolates were positive by spoligotyping and spoligotyping International type (SIT) 53, SIT 37, and SIT 149 were the dominant spoligotypes; each consisting of 19%, 15.5%, and10.3% of the isolates, respectively. The majority of the isolates (89.7%) were members of the Euro-American (EA) major lineage. MIRU-VNTR identified Ethiopia_3, Delhi/CAS, Ethiopia_2, TUR, X-type, Ethiopia_H37Rv-like strain, Haarlem and Latin-American Mediterranean (LAM) sub lineages. The proportion of clustering was 77.6% (45/58) in spoligotyping while it was 39.7% (23/58) in 24-loci MIRU-VNTR typing. Furthermore, the proportion of clustering was significantly lowered to 10.3% (6/58) when a combination of spoligotyping and 24-loci MIRU-VNTRplus was used. The recent transmission index (RTI) recorded by spoligotyping, 24-loci MIRU-VNTR typing, and a combination of the two genotyping methods were 58.6%, 27.6% and 5.2%, respectively. Young age and living in groups were significantly associated with strain clustering (P < 0.05). The drug sensitivity test (DST) result showed 8.9% (4/58) of the isolates were resistant to one or more first line ant-TB drugs; but multidrug resistant isolate was not detected. Clustering and RTI could suggest the transmission of TB in the homeless individuals, which could suggest a similar pattern of transmission between homeless individuals and the general population. Hence, the TB control program should consider homeless individuals during the implementation of TB control program.

Implementation of national whole-genome sequencing of Mycobacterium tuberculosis, National Public Health Laboratory, Singapore, 2019-2022.

The National Tuberculosis Programme (NTBP) monitors the occurrence and spread of tuberculosis (TB) and multidrug-resistant TB (MDR-TB) in Singapore. Since 2020, whole-genome sequencing (WGS) of Mycobacterium tuberculosis isolates has been performed at the National Public Health Laboratory (NPHL) for genomic surveillance, replacing spoligotyping and mycobacterial interspersed repetitive unit-variable number tandem repeats analysis (MIRU-VNTR). Four thousand three hundred and seven samples were sequenced from 2014 to January 2023, initially as research projects and later developed into a comprehensive public health surveillance programme. Currently, all newly diagnosed culture-positive cases of TB in Singapore are prospectively sent for WGS, which is used to perform lineage classification, predict drug resistance profiles and infer genetic relationships between TB isolates. This paper describes NPHL's operational and technical experiences with implementing the WGS service in an urban TB-endemic setting, focusing on cluster detection and genomic drug susceptibility testing (DST). Cluster detection: WGS has been used to guide contact tracing by detecting clusters and discovering unknown transmission networks. Examples have been clusters in a daycare centre, housing apartment blocks and a horse-racing betting centre. Genomic DST: genomic DST prediction (gDST) identifies mutations in core genes known to be associated with TB drug resistance catalogued in the TBProfiler drug resistance mutation database. Mutations are reported with confidence scores according to a standardized approach referencing NPHL's internal gDST confidence database, which is adapted from the World Health Organization (WHO) TB drug mutation catalogue. Phenotypic-genomic concordance was observed for the first-line drugs ranging from 2959/2998 (98.7 %) (ethambutol) to 2983/2996 (99.6 %) (rifampicin). Aspects of internal database management, reporting standards and caveats in results interpretation are discussed.

Genotyping methods and their contributions to the study of tuberculosis dynamic in Latin America.

Mycobacterium tuberculosis genotyping has impacted evolutionary studies worldwide. Nonetheless, its application and the knowledge generated depend on the genetic marker evaluated and the detection technologies that have evolved over the years. Here we describe the timeline of main genotypic methods related to M. tuberculosis in Latin America and the main findings obtained. Systematic searches through the PubMed database were performed from 1993 to May 2021. A total of 345 articles met the inclusion criteria and were selected. Spacer oligonucleotide typing (spoligotyping) was the most widely used method in Latin America, with decreasing use in parallel with increasing use of mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR) and whole genome sequencing (WGS). Among the countries, Brazil, Mexico, and Argentina had the most publications, and a considerable part of the articles were in collaboration with Latin American or non-Latin American institutions; a small proportion of studies needed partnerships to perform the genotypic methods. The genotypic methods allowed the identification of M. tuberculosis genotypes with greater capacity for clonal expansion and revealed the predominance of the Euro-American lineage in Latin America. There was a notable presence of the Beijing family in Peru and Colombia. The data obtained demonstrated the importance of expanding collaborative networks of tuberculosis (TB) research groups to countries with low productivity in this area, the commitment of the few Latin American countries to advance TB research, as well as the inestimable value of building a Latin America database, considering ease of population mobility between countries.

Heterogeneity of Mycobacterium tuberculosis Strains Circulating in Panama's Western Region.

Tuberculosis remains a challenge in both rural and urban areas. Although a majority of countries display a higher burden in urban areas compared with rural areas, Panama continues to report the highest mortality rate in Central America. Urban areas, such as Panama City, report a high tuberculosis burden, whereas Panama's western region, including the provinces of Chiriquí, Bocas del Toro (both semiurban) and Ngäbe-Bugle (rural), show a lower burden. We aimed to identify highly transmitted Mycobacterium tuberculosis strains within rural and semiurban settings of Panama's western region during a 3-year period (2017, 2019, 2021). We randomly selected 87 M. tuberculosis isolates from a biobank from Panama's western region and analyzed them using allele-specific oligonucleotide polymerase chain reaction and 24-mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR). Our results show only 11.7% (10/85) of M. tuberculosis strains identified as prevalent A-Beijing, B-Haarlem, or C-LAM Strains. We found a low prevalence of A, B, and C M. tuberculosis strains in both rural and semirural settings compared with isolates collected from the Eastern Colon Province. MIRU-VNTR genotyping revealed a high degree of diversity with no clusters with single loci variation of ≥ 2 loci. These results support the notion that tuberculosis prevalence in the rural and semiurban western region of Panama are not due to previously described highly transmitted strains but is influenced instead by other health determinants, including poor health system access and a lack of systematic transmission chain monitoring. For remote rural and semiurban settings, we recommend allocating resources to reinforce efforts to prevent tuberculosis spread.

Genetic Diversity and Population Structure of Mycobacterium bovis at the Human-Animal-Ecosystem Interface in France: "A One Health Approach".

Mycobacterium bovis infects cattle and wildlife, and also causes a small proportion of tuberculosis cases in humans. In most European countries, M. bovis infections in cattle have been drastically reduced, but not eradicated. Here, to determine the M. bovis circulation within and between the human, cattle, and wildlife compartments, we characterized by spoligotyping and mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR) typing the genetic diversity of M. bovis isolates collected from humans, cattle, and wildlife in France from 2000 to 2010. We also assessed their genetic structure within and among the different host groups, and across time and space. The M. bovis genetic structure and its spatiotemporal variations showed different dynamics in the human and animal compartments. Most genotypes detected in human isolates were absent in cattle and wildlife isolates, possibly because in patients, M. bovis infection was contracted abroad or was the reactivation of an old lesion. Therefore, they did not match the genetic pool present in France during the study period. However, some human-cattle exchanges occurred because some genotypes were common to both compartments. This study provides new elements for understanding M. bovis epidemiology in France, and calls for increased efforts to control this pathogen worldwide.

Phylogenetic relationships of Mycobacterium tuberculosis isolates in Poland: The emergence of Beijing genotype among multidrug-resistant cases.

The epidemiological situation of tuberculosis (TB) in Poland urges for its continuous and scrupulous monitoring. The objective of this study was to explore the genetic diversity of multidrug-resistant (MDR) and drug-susceptible (DS) Mycobacterium tuberculosis isolates from Poland with a combination of spoligotyping and high-resolution mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR) analysis. The results were placed in the Northern and Eastern Europe context. The study included 89 (39 MDR and 50 DS) M. tuberculosis isolates collected from as many patients between 2018 and 2021 in Poland. The analysis was done using spoligotyping, and MIRU-VNTR typing at 24 standard loci. The data were compared to those available on Poland and neighbors and global M. tuberculosis datasets. The main identified families were Beijing (28.1%) and Haarlem (16.8%) while 34.8% of isolates were in the heterogeneous L4-unclassified group. Although the Beijing family was the most prevalent (61.5%) among MDR-TB cases, it accounted for only 2% of DS isolates. Among foreign-born patients, a higher ratio of MDR isolates were observed when compared with those who Poland-born (64.3% vs. 40%). Furthermore, all patients from the Former Soviet Union (FSU) countries were infected with MDR-TB. Whereas DS M. tuberculosis population in Poland is dominated by L4 isolates, MDR isolates are mostly of the Beijing genotype. The rise in the prevalence of the Beijing isolates in Poland, coupled with high proportion of the Beijing genotype among foreign-born TB patients may reflect an ongoing transmission of this family, imported to Poland mainly from FSU countries.

The mutation rate of rpoB gene showed an upward trend with the increase of MIRU10, MIRU39 and QUB4156 repetitive number

BackgroundMycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR) is a frequently used typing method for identifying the Beijing genotype of Mycobacterium tuberculosis (Mtb), which is easily transformed into rifampicin (RIF) resistance. The RIF resistance of Mtb is considered to be highly related with the mutation of rpoB gene. Therefore, this study aimed to analyze the relationship between the repetitive number of MIRU loci and the mutation of rpoB gene.MethodsAn open-source whole-genome sequencing data of Mtb was used to detect the mutation of rpoB gene and the repetitive number of MIRU loci by bioinformatics methods. Cochran-Armitage analysis was performed to analyze the trend of the rpoB gene mutation rate and the repetitive number of MIRU loci.ResultsAmong 357 rifampicin-resistant tuberculosis (RR-TB), 304 strains with mutated rpoB genes were detected, and 6 of 67 rifampicin susceptible strains were detected mutations. The rpoB gene mutational rate showed an upward trend with the increase of MIRU10, MIRU39, QUB4156 and MIRU16 repetitive number, but only the repetitive number of MIRU10, MRIU39 and QUB4156 were risk factors for rpoB gene mutation. The Hunter-Gaston discriminatory index (HGDI) of MIRU10 (0.65) and QUB4156 (0.62) was high in the overall sample, while MIRU39 (0.39) and MIRU16 (0.43) showed a moderate discriminatory Power.ConclusionThe mutation rate of rpoB gene increases with the addition of repetitive numbers of MIRU10, QUB4156 and MIRU39 loci.

Recent progress in the genotyping of bovine tuberculosis and its rapid diagnosis via nanoparticle-based electrochemical biosensors.

Bovine tuberculosis (bTB) is considered a worldwide infectious zoonotic disease. Mycobacterium bovis causes bTB disease. It is one of the Mycobacterium tuberculosis complex (MTBC) members. MTBC is a clonal complex of close relatives with approximately 99.95% similarity. M. bovis is a spillover pathogen that can transmit from animals to humans and rarely from humans to animals with contact. Genotyping techniques are important to discriminate and differentiate between MTBC species. Spoligotyping and mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR) are widely used but they have some limitations. As an alternative, whole genome sequencing approaches have been utilized due to their high-resolution power. They are employed in typing M. bovis and explain the evolutionary and phylogenetic relationships between isolates. The control of bTB disease has attracted a large amount of attention. Rapid and proper diagnosis is necessary for monitoring the disease as an initial step for its control and treatment. Nanotechnology has a potential impact on the rapid diagnosis and treatment of bTB through the use of nanocarrier and metal nanoparticles (NPs). Special attention has been paid to voltammetric and impedimetric electrochemical strategies as facile, sensitive, and selective methods for the efficient detection of tuberculosis. The efficacy of these sensors is enhanced in the presence of NPs, which act as recognition and/or redox probes. Gold, silver, copper, cobalt, graphene, and magnetic NPs, as well as polypyrrole nanowires and multiwalled carbon nanotubes have been employed for detecting tuberculosis. Overall, NP-based electrochemical sensors represent a promising tool for the diagnosis of bTB.

The shortcut of mycobacterial interspersed repetitive unit-variable number tandem repeat typing for Mycobacterium tuberculosis differentiation.

The 24-loci mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR) genotyping has been used as an international standard method for Mycobacterium tuberculosis (Mtb) genotyping. However, different optimized VNTR loci sets for improving the discrimination of specific Mtb genotypes have been proposed. In this regard, we investigated the efficacy of accumulation of the percentage differences (APDs) compared with the least absolute shrinkage and selection operator (LASSO) regression strategy to identify a customized genotype-specific VNTR loci set which provides a resolution comparable to 24-loci MIRU-VNTR in divergent Mtb populations. We utilized Spoligotyping and 24-loci MIRU-VNTR typing for genotyping 306 Mtb isolates. The APD and LASSO regression approaches were used to identify a customized VNTR set in our studied isolates. Besides, the Hunter-Gaston discriminatory index (HGDI), sensitivity, and specificity of each selected loci set were calculated based on both strategies. The selected loci based on LASSO regression compared with APD-based loci showed a better discriminatory power for identifying all studied genotypes except for T genotype, which APD-based loci showed promising discriminative power. Our findings suggested the LASSO regression rather than the APD approach is more effective in the determination of possible discriminative VNTR loci set to precise discrimination of our studied Mtb population and may be beneficial to be used in finding reduced number loci sets in other Mtb genotypes or sublineages. Moreover, we proposed customized genotype-specific MIRU-VNTR loci sets based on the LASSO regression and APD approaches for precise Mtb strains identification. As the proposed VNTR sets offered a comparable discriminatory power to the standard 24 MIRU-VNTR loci set could be promising alternatives to the standard genotyping for using in resource-limited settings.

The potential risk of international spread of Mycobacterium bovis associated with movement of alpacas

IntroductionThe study highlights the transboundary nature of tuberculosis (TB) in alpacas and the failure of current ante-mortem testing protocols (the tuberculin skin and Enferplex Camelid TB tests) to identify TB-free alpaca herds and individuals for export. Our research and the available literature indicate that the alpaca (Vicugna pacos) is extremely susceptible to Mycobacterium bovis infection, and that testing periodicity fails to take into account that animals do not manifest disease symptoms for a long time. The skin test failed to identify Mycobacterium bovis infection in two alpacas prior to their movement from the UK to Poland. The animals were purchased by a breeding centre in Poland, and were then shown at an international animal exhibition. The last owner of the alpacas before their deaths from TB bought the infected animals unwittingly in order to run rehabilitation activities with disabled children on his farm.Material and MethodsThoracic lymph node, lung and liver tissue samples obtained at necropsy were examined histopathologically after Ziehl–Neelsen staining. Tissue samples were homogenised and mycobacteria present there were cultured on Stonebrink’s medium during a 6-week incubation. A commercial test using polymorphism of the chromosomal direct repeat region provided species identification and additional identification was by spacer oligonucleotide typing and mycobacteria interspersed repetitive unit–variable number tandem repeat analysis with a gel electrophoresis protocol.ResultsThe microbiological examination confirmed multiorgan TB caused by the SB0666 spoligotype of Mycobacterium bovis.ConclusionDue to the suboptimal performance of current diagnostic tests for TB in alpacas, there is a risk that infected animals may be moved unwittingly. A risk of TB spread associated with the international movement of alpacas is implied by this study.

Transmission of multidrug-resistant Mycobacterium tuberculosis in Wuhan, China: A retrospective molecular epidemiological study.

How multidrug-resistant tuberculosis (MDR-TB) spreads and expands in Wuhan population is not clear. The study aimed to determine the transmission patterns of MDR-TB in Wuhan city, China, including 149 patients with MDR-TB.Tuberculosis isolates were genotyped by deletion-targeted multiplex polymerase chain reaction, mycobacterial interspersed repetitive unit-variable number tandem repeat typing, and sequencing of drug resistance-associated genes. The risk factors of genomic-clustering were analyzed with logistic regression. The genomic-clustering patients were deeply investigated.The analysis identified 111 unique and 11 clustered genotypes (38 isolates). The clustering rate was 25.50% and the minimum estimate proportion of recent transmission was 18.12%. Two clusters (5 isolates) shared the same mutation, the remain 9 clusters (33 isolates) had different mutation. Logistic regression showed that older than 60 years (adjusted OR 2.360, 95% CI:1.052-5.292) was an independent factor associated with the genomic-clustering of MDR-TB. Among the 38 genomic-clustering cases, 14 cases had epidemiological transmission links. The most common type of transmission link was social contact.The local transmission of MDR-TB in Wuhan was really an issue. The elderly population might be the high-risk groups for transmission of MDR-TB, and the community or public transportation might be the main transmission places.

Validation and comparative analysis of kogene mycobacterial interspersed repetitive unit-variable number of tandem repeat typing kit and its application on clinically isolated mycobacterium tuberculosis samples from national tuberculosis hospital, Republic of Korea.

Tuberculosis (TB) remains a serious public health burden in Korea. Mycobacterial Interspersed Repetitive Unit-Variable Number Tandem Repeat (MIRU-VNTR) is preferred for epidemiological TB investigation. Until recently, the difficulty lies in epidemiological TB investigation due to the absence of commercialized MIRU-VNTR in Korea. Here, we have evaluated the newly designed MIRU-VNTR kit by Kogenebiotech, Korea. A total of 200 samples, where 100 are Mycobacrerium tuberculosis (M. tuberculosis), and the other 100 are non-M. tuberculosis, were used. Initially, the Kogenebiotech MIRU-VNTR typing kit (KoMIRU) was compared with Multilocus Variable Number Tandem Repeat Genotyping of M. tuberculosis typing kit (MVNTR) by Philip Supply for validation purpose. Then, Limit of Detection for DNA copies was optimized. Finally, KoMIRU and Genoscreen MIRU-VNTR typing kit (GeMIRU) were tested and comparatively analyzed for its specificity and sensitivity. The study showed that the KoMIRU has slightly higher discriminatory power over MVNTR, 100% versus 97.5%. In comparative analysis, the KoMIRU has shown comparable capability as GeMIRU, showing 100% for sensitivity and specificity with a 95% CI value of 96.38 to 100.00%. Also, no discrepancies were observed on discriminated lineage strains between KoMIRU and GeMIRU. Out of 100, 84 were identified as Beijing strains, and remains were identified as NEW-1 (n = 8), Uganda (n = 6), East African Indian (EAI) (n = 6), Turkey (n = 2), and Haarlem (n = 1). In this study, KoMIRU has shown a comparable capability to GeMIRU. Furthermore, previous researches had suggested an association between lineage strains and drug resistance; hence, the implementation of KoMIRU can help in TB control and prevention.

Molecular detection of mycobacterium tuberculosis complex species in triatomines found in urban households and Peridomiciles in a city with high prevalence of tuberculosis in Northeastern Brazil.

Triatomine insects, native to northeastern Brazil, have been found in the urban peridomicile. The city of Sobral has a high number of tuberculosis cases and several triatomine species. This study investigates the presence of mycobacteria, particularly Mycobacterium tuberculosis complex (MTBC) species, in triatomines captured in the urban perimeter of Sobral. We analyzed 167 triatomines captured in urban households and peridomiciles of Sobral. Mycobacteria were identified by the PRA-hsp65 method followed by partial sequencing of the hsp65 and rpoB genes. The sequences confirmed as MTBC were also typed by mycobacterial interspersed repetitive units-variable number tandem repeats (MIRU-VNTR) and spoligotyping. Triatoma brasiliensis (38.6%), Triatoma pseudomaculata (32.9%), Panstrongylus lutzi (24.3%) were the most frequently identified. In 51.1% (70/167) of them, species of the Mycobacteriaceae family were detected by PRA-hsp65; of these, 31.4% (22/70) were identified as belonging to MTBC species. Nine (12.9%) of the triatomine samples were confirmed by sequencing as belonging to MTBC species. MIRU-VNTR genotyping suggests that the presence of different MTBC sublines in the triatomines should be investigated. This is the first report of MTBC lineages in triatomine insects. These results indicate the migration and adaptation of these insects in an urban setting.

Mixed tuberculosis infections in Northwest of Iran.

Primary Mycobacterium tuberculosis (MTB) infection doesn't provide protection against secondary infection and patients can suffer from multiple strains of M. tuberculosis simultaneously. The aim of this study was to use molecular genotyping to identify cases of mixed infection in Northwest of Iran. One hundred and twenty-one positive culture isolates of M. tuberculosis were prepared from patients consecutively in Northwest of Iran from March 2017 to March 2018 and then microevolution and mix infection were assessed using the mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR) method. MIRU-VNTR analysis revealed that nine samples (7.3%) had double alleles in at least one locus, as observed by five cases of microevolution, and four cases (3.3%) of mixed infection. According to this study, mixed infection in Northwest of Iran has significantly decreased compared to 13 years ago (7.1% decreased to 3.3%), and in order to eradicate tuberculosis it is necessary to identify all cases of mixed infection, at least in recurrent cases, in the future.

Genetic diversity and characterization of M. tuberculosis isolates causing extrapulmonary tuberculosis in Bangladesh.

Tuberculosis (TB) remains one of the leading causes of death and Bangladesh ranks 7th among the highest TB burden countries. Though molecular epidemiological data for pulmonary TB (PTB) have previously been described in Bangladesh, data on the molecular characterization and clinical association with different lineages among extrapulmonary TB (EPTB) is lacking. The aim of the study was to investigate the molecular characterization and lineage distribution of M. tuberculosis isolates obtained from patients with EPTB in Bangladesh. Between November 2015 and March 2017, a total of 1,340 EPTB specimens including lymph node, pus, tissue, ascitic fluid, cerebrospinal fluid, pleural fluid, abscess wall, urine etc. were collected from four tertiary care hospitals in Dhaka city, Bangladesh. Among the specimens, 141 were found positive on solid culture. Molecular characterization of the 141 isolates was done by deletion analysis, spoligotyping and Mycobacterial Interspersed Repetitive Unit-Variable Number Tandem Repeats (MIRU-VNTR) analysis. Among the 141 isolates, 80 (56.7%) were found as 'modern' and the remaining 61 (43.3%) were 'ancestral' type. Spoligotyping results revealed 91 distinct patterns of which 74 isolates were unique and the remaining 67 were divided into 17 distinct clusters. East African- Indian (EAI) lineage was the most predominant, comprising 26 (18.4%) isolates, followed by the Beijing lineage (14.2%). 15-loci MIRU-VNTR analysis revealed that 132 isolates (93.5%) had unique patterns, whereas only 9 (6.5%) isolates were grouped into 4 distinct clusters. In conclusion, the study findings provide a first insight into genetic diversity of EPTB isolates in Bangladesh. The present study demonstrated that 'modern' strains were more prevalent among the EPTB cases, while EAI lineages were predominantly circulating in this region.

Genetic Diversity and Drug Susceptibility Profiles of Multidrug-Resistant Tuberculosis Strains in Southeast China.

BackgroundMultidrug-resistant tuberculosis (MDR-TB) isolates collected from Fujian province, China were assessed for molecular epidemiological characteristics. Analysis of isolate genotype profiles revealed that the Beijing genotype was associated with especially high drug resistance and community transmission rates.MethodsA total of 119 MDR-TB isolates obtained from TB patients in Fujian province were typed using 24–locus mycobacterium interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR) typing and spoligotyping. Drug susceptibility testing of all isolates was conducted using the L-J proportion method, with pyrazinamide (PZA) susceptibility testing conducted using the Mycobacterium Growth Indicator Tube System 960 (MGIT 960).ResultsWe obtained 26 spoligotypes for the 119 isolates examined in this work. Spoligotyping results revealed that 80 (67.2%) isolates possessed the Beijing family genotypic profiles. Patients aged 25–44 years and ≥45 years were most likely to be infected by non-Beijing genotypes. The percentage of clustered cases with both PZA and ofloxacin (OFLX) resistance was significantly greater than the corresponding percentage for non-clustered cases. Of 44 PZA-resistant isolates, 28 isolates (63.6%) harbored pncA mutations, while pncA mutations were only detected in 7 (9.3%) PZA-susceptible isolates.ConclusionOur data demonstrate that the Beijing genotype is the dominant lineage among MDR-TB strains circulating in Fujian. Thus, MDR-TB infections occurring within this province are not likely associated with recent transmission events. PZA and fluoroquinolone resistance profiles were found to be associated with clustered isolates. Mutation of pncA is the main driver of MDR-TB PZA resistance and is associated with mutation sites scattered throughout the entire pncA protein-coding region.

Pulmonary Tuberculosis Outbreak in a High School, China

This study reports an outbreak of Tuberculosis (TB) in a high school in Hunan province, China during January 2017-April 2018. Contact investigation and TB screening were conducted through symptom screening, tuberculin skin testing, chest radiography and smear examination. Identification of positive isolates and drug susceptibility phenotype were assessed by standard method. Mycobacterial Interspersed Repetitive Units-Variable Number Tandem Repeats (MIRU-VNTR) and Whole Genome Sequencing (WGS) were performed to investigate the relationships among the positive isolates. A total of 90 students and one teacher were diagnosed active pulmonary TB among 2908 students and 188 staff, with an attack rate of 2.94%. Thirteen positive isolates were identified as drug susceptible Beijing family of Mycobacterium tuberculosis. Results of MIRU-VNTR typing and WGS revealed two clones of Mycobacterium tuberculosis circulating during outbreak. One hundred and twenty-nine Single Nucleotide Polymorphisms (SNPs) discriminated the isolates in two clusters; the maximum number of SNPs between any pair of isolates in each cluster was five or fewer. Our findings highlight the importance of early identification and isolation of the TB cases to prevent spread of TB. WGS provides better resolution than MIRU-VNTR to identify recent transmission in TB outbreak.

Population structure and transmission of Mycobacterium bovis in Ethiopia.

Bovine tuberculosis (bTB) is endemic in cattle in Ethiopia, a country that hosts the largest national cattle herd in Africa. The intensive dairy sector, most of which is peri-urban, has the highest prevalence of disease. Previous studies in Ethiopia have demonstrated that the main cause is Mycobacterium bovis , which has been investigated using conventional molecular tools including deletion typing, spoligotyping and Mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR). Here we use whole-genome sequencing to examine the population structure of M. bovis in Ethiopia. A total of 134 M . bovis isolates were sequenced including 128 genomes from 85 mainly dairy cattle and six genomes isolated from humans, originating from 12 study sites across Ethiopia. These genomes provided a good representation of the previously described population structure of M. bovis , based on spoligotyping and demonstrated that the population is dominated by the clonal complexes African 2 (Af2) and European 3 (Eu3). A range of within-host diversity was observed amongst the isolates and evidence was found for both short- and long-distance transmission. Detailed analysis of available genomes from the Eu3 clonal complex combined with previously published genomes revealed two distinct introductions of this clonal complex into Ethiopia between 1950 and 1987, likely from Europe. This work is important to help better understand bTB transmission in cattle in Ethiopia and can potentially inform national strategies for bTB control in Ethiopia and beyond.