Long-term population-based genotyping study of Mycobacterium tuberculosis complex isolates in the French departments of the Americas

Migration in French Guiana: Implications in health and infectious diseases

In French Guiana, more than a third of the population, and nearly half of the adults, are of foreign origin. This immigration is explained by the French standard of living, which is attractive to nationals of surrounding countries. Infectious diseases remain in the top 10 causes of premature death, often in the most precarious populations. In this context we aimed to synthesize the state of the knowledge regarding immigration and infectious diseases in French Guiana and the general implications that follow this diagnosis. For HIV, although the majority of patients are of foreign origin, estimates of the presumed date of infection based on CD4 erosion modelling and from molecular analyses suggest that the majority of transmissions in foreign-born individuals occur in French Guiana and that the Guiana shield has been a crossroad between Latin America and the Caribbean. Among key populations bridging these regions illegal gold miners are very mobile and have the greatest proportion B Caribbean HIV viruses. Gold miners have been a key vulnerable population for falciparum malaria and other tropical diseases such as leishmaniasis, leprosy, or leptospirosis. The complex history of migrations in French Guiana and on the Guiana Shield is also reflected in the fingerprinting of mycobacterium tuberculosis and the high incidence of tuberculosis in French Guiana, notably in immigrants, reflects the incidences in the countries of origin of patients. The high burden of infectious diseases in immigrants in French Guiana is first and foremost a reflection of the precarious living conditions within French Guiana and suggests that community-based proactive interventions are crucial to reduce transmission, morbidity, and mortality from infectious diseases.

The future of CRISPR in Mycobacterium tuberculosis infection

Clustered Regularly Interspaced Short Palindromic repeats (CRISPR)-Cas systems rapidly raised from a bacterial genetic curiosity to the most popular tool for genetic modifications which revolutionized the study of microbial physiology. Due to the highly conserved nature of the CRISPR locus in Mycobacterium tuberculosis, the etiological agent of one of the deadliest infectious diseases globally, initially, little attention was paid to its CRISPR locus, other than as a phylogenetic marker. Recent research shows that M. tuberculosis has a partially functional Type III CRISPR, which provides a defense mechanism against foreign genetic elements mediated by the ancillary RNAse Csm6. With the advent of CRISPR-Cas based gene edition technologies, our possibilities to explore the biology of M. tuberculosis and its interaction with the host immune system are boosted. CRISPR-based diagnostic methods can lower the detection threshold to femtomolar levels, which could contribute to the diagnosis of the still elusive paucibacillary and extrapulmonary tuberculosis cases. In addition, one-pot and point-of-care tests are under development, and future challenges are discussed. We present in this literature review the potential and actual impact of CRISPR-Cas research on human tuberculosis understanding and management. Altogether, the CRISPR-revolution will revitalize the fight against tuberculosis with more research and technological developments.

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.

Geospatial distribution of Mycobacterium tuberculosis genotypes in Africa

Objective

To investigate the distribution of Mycobacterium tuberculosis genotypes across Africa.

Methods

The SITVIT2 global repository and PUBMED were searched for spoligotype and published genotype data respectively, of M. tuberculosis from Africa. M. tuberculosis lineages in Africa were described and compared across regions and with those from 7 European and 6 South-Asian countries. Further analysis of the major lineages and sub-lineages using Principal Component analysis (PCA) and hierarchical cluster analysis were done to describe clustering by geographical regions. Evolutionary relationships were assessed using phylogenetic tree analysis.

Results

A total of 14727 isolates from 35 African countries were included in the analysis and of these 13607 were assigned to one of 10 major lineages, whilst 1120 were unknown. There were differences in geographical distribution of major lineages and their sub-lineages with regional clustering. Southern African countries were grouped based on high prevalence of LAM11-ZWE strains; strains which have an origin in Portugal. The grouping of North African countries was due to the high percentage of LAM9 strains, which have an origin in the Eastern Mediterranean region. East African countries were grouped based on Central Asian (CAS) and East-African Indian (EAI) strain lineage possibly reflecting historic sea trade with Asia, while West African Countries were grouped based on Cameroon lineage of unknown origin. A high percentage of the Haarlem lineage isolates were observed in the Central African Republic, Guinea, Gambia and Tunisia, however, a mixed distribution prevented close clustering.

Conclusions

This study highlighted that the TB epidemic in Africa is driven by regional epidemics characterized by genetically distinct lineages of M. tuberculosis. M. tuberculosis in these regions may have been introduced from either Europe or Asia and has spread through pastoralism, mining and war. The vast array of genotypes and their associated phenotypes should be considered when designing future vaccines, diagnostics and anti-TB drugs.

Molecular characterization and drug susceptibility profile of Mycobacterium tuberculosis isolates from Northeast Bangladesh

Tuberculosis (TB) remains a major public health problem worldwide including in Bangladesh. Molecular epidemiological tools provide genotyping profiles of Mycobacterium tuberculosis (M. tuberculosis) strains that can give insight into the transmission of TB in a specific region. The objective of the study was to identify the genetic diversity and drug susceptibility profile of M. tuberculosis strains circulating in the northeast Bangladesh. A total of 244 smear-positive sputum specimens were collected from two referral hospitals in Mymensingh and Netrakona districts. The isolated strains were genotyped by deletion analysis, spoligotyping, and MIRU-VNTR typing. We also analyzed the distributions of drug susceptibility pattern and demographic data among different genotypes. All isolates were identified as M. tuberculosis and among them 167 strains (68.44%) were 'ancestral' and the remaining 77 (31.56%) were 'modern' type. Spoligotyping analysis yielded 119 distinct patterns, among them, 86 isolates had unique patterns and the remaining 158 were grouped into 33 distinct clusters containing 2 to 18 isolates. The predominant spoligotypes belong to the EAI lineage strains, comprising 66 (27.04%) isolates followed by Beijing (7.38%), T1 (6.15%), CAS1-Delhi (5.33), LAM9 (3.28%), MANU-2 and X2. MIRU-VNTR analysis revealed 167 isolates (68%) had unique patterns, whereas 77 (32%) were grouped into 26 clusters and the rate of recent transmission was 20.9%, suggesting that the majority of TB cases in this region are caused by the reactivation of previous TB infections rather than recent transmission. About 136 (55.7%) isolates were sensitive to four anti-TB drugs, 69 (28.3%) were resistant to one or more (except rifampicin and isoniazid combination) drugs and 39 (15.9%) were MDR. In conclusion, our study provides a first insight into molecular characterization and drug resistance profile of M. tuberculosis strains in northeast Bangladesh which will ultimately contribute to the national TB control program.

Spatiotemporal Clustering of Mycobacterium tuberculosis Complex Genotypes in Florida: Genetic Diversity Segregated by Country of Birth

Background

Tuberculosis (TB) is caused by members of the Mycobacterium tuberculosis complex (MTBC). Although the MTBC is highly clonal, between-strain genetic diversity has been observed. In low TB incidence settings, immigration may facilitate the importation of MTBC strains with a potential to complicate TB control efforts.

Methods

We investigated the genetic diversity and spatiotemporal clustering of 2,510 MTBC strains isolated in Florida, United States, between 2009 and 2013 and genotyped using spoligotyping and 24-locus MIRU-VNTR. We mapped the genetic diversity to the centroid of patient residential zip codes using a geographic information system (GIS). We assessed transmission dynamics and the influence of immigration on genotype clustering using space-time permutation models adjusted for foreign-born population density and county-level HIV risk and multinomial models stratified by country of birth and timing of immigration in SaTScan.

Principal Findings

Among the 2,510 strains, 1,245 were reported among foreign-born persons; including 408 recent immigrants (<5 years). Strain allelic diversity (h) ranged from low to medium in most locations and was most diverse in urban centers where foreign-born population density was also high. Overall, 21.5% of cases among U.S.-born persons and 4.6% among foreign-born persons clustered genotypically and spatiotemporally and involved strains of the Haarlem family. One Haarlem space-time cluster identified in the mostly rural northern region of Florida included US/Canada-born individuals incarcerated at the time of diagnosis; two clusters in the mostly urban southern region of Florida were composed predominantly of foreign-born persons. Both groups had HIV prevalence above twenty percent.

Conclusions/Significance

Almost five percent of TB cases reported in Florida during 2009–2013 were potentially due to recent transmission. Improvements to TB screening practices among the prison population and recent immigrants are likely to impact TB control. Due to the monomorphic nature of available markers, whole genome sequencing is needed to conclusively delineate recent transmission events between U.S. and foreign-born persons.

Genetic Diversity of Mycobacterium tuberculosis Isolates from Assam, India: Dominance of Beijing Family and Discovery of Two New Clades Related to CAS1_Delhi and EAI Family Based on Spoligotyping and MIRU-VNTR Typing

Tuberculosis (TB) is one of the major public health concerns in Assam, a remote state located in the northeastern (NE) region of India. The present study was undertaken to explore the circulating genotypes of Mycobacterium tuberculosis complex (MTBC) in this region. A total of 189 MTBC strains were collected from smear positive pulmonary tuberculosis cases from different designated microscopy centres (DMC) from various localities of Assam. All MTBC isolates were cultured on Lowenstein-Jensen (LJ) media and subsequently genotyped using spoligotyping and 24-loci mycobacterial interspersed repetitive units-variable number of tandem repeats (MIRU-VNTR) typing. Spoligotyping of MTBC isolates revealed 89 distinct spoligo patterns. The most dominant MTBC strain belonged to Beijing lineage and was represented by 35.45% (n = 67) of total isolates, followed by MTBC strains belonging to Central Asian-Delhi (CAS/Delhi) lineage and East African Indian (EAI5) lineage. In addition, in the present study 43 unknown spoligo patterns were detected. The discriminatory power of spoligotyping was found to be 0.8637 based on Hunter Gaston Discriminatory Index (HGDI). On the other hand, 24-loci MIRU-VNTR typing revealed that out of total 189 MTBC isolates from Assam 185 (97.9%) isolates had unique MIRU-VNTR profiles and 4 isolates grouped into 2 clusters. Phylogenetic analysis of 67 Beijing isolates based on 24-loci MIRU-VNTR typing revealed that Beijing isolates from Assam represent two major groups, each comprising of several subgroups. Neighbour-Joining (NJ) phylogenetic tree analysis based on combined spoligotyping and 24-loci MIRU-VNTR data of 78 Non-Beijing isolates was carried out for strain lineage identification as implemented by MIRU-VNTRplus database. The important lineages of MTBC identified were CAS/CAS1_Delhi (41.02%, n = 78) and East-African-Indian (EAI, 33.33%). Interestingly, phylogenetic analysis of orphan (23.28%) MTBC spoligotypes revealed that majority of these orphan isolates from Assam represent two new sub-clades Assam/EAI and Assam/CAS. The prevalence of multidrug resistance (MDR) in Beijing and Non-Beijing strains was found to be 10.44% and 9.01% respectively. In conclusion, the present study has shown the predominance of Beijing isolates in Assam which is a matter of great concern because Beijing strains are considered to be ecologically more fit enabling wider dissemination of M. tuberculosis. Other interesting finding of the present study is the discovery of two new clades of MTBC isolates circulating in Assam. More elaborate longitudinal studies are required to be undertaken in this region to understand the transmission dynamics of MTBC.

A first insight on the population structure of Mycobacterium tuberculosis complex as studied by spoligotyping and MIRU-VNTRs in Santiago, Chile

Tuberculosis (TB) remains a significant public health problem worldwide, but the ecology of the prevalent mycobacterial strains, and their transmission, can vary depending on country and region. Chile is a country with low incidence of TB, that has a geographically isolated location in relation to the rest of South American countries due to the Andes Mountains, but recent migration from neighboring countries has changed this situation. We aimed to assess the genotypic diversity of Mycobacterium tuberculosis complex (MTBC) strains in Santiago, Chile, and compare with reports from other Latin-American countries. We analyzed MTBC isolates from pulmonary tuberculosis cases collected between years 2008 and 2013 in Central Santiago, using two genotyping methods: spoligotyping and 12-loci mycobacterial interspersed repetitive unit-variable number of tandem repeats (MIRU-VNTRs). Data obtained were analyzed and compared to the SITVIT2 database. Mean age of the patients was 47.5 years and 61% were male; 11.6% were migrants. Of 103 strains (1 isolate/patient) included, there were 56 distinct spoligotype patterns. Of these, 16 strains (15.5%) corresponded to orphan strains in the SITVIT2 database, not previously reported. Latin American and Mediterranean (LAM) (34%) and T (33%) lineages were the most prevalent strains, followed by Haarlem lineage (16.5%). Beijing family was scarcely represented with only two cases (1.9%), one of them isolated from a Peruvian migrant. The most frequent clustered spoligotypes were SIT33/LAM3 (10.7%), SIT53/T1 (8.7%), SIT50/H3 (7.8%), and SIT37/T3 (6.8%). We conclude that LAM and T genotypes are the most prevalent genotypes of MTBC in Santiago, Chile, and together correspond to almost two thirds of analyzed strains, which is similar to strain distribution reported from other countries of Latin America. Nevertheless, the high proportion of SIT37/T3, which was rarely found in other Latin American countries, may underline a specific history or demographics of Chile related to probable human migrations and evolutions.

Finer characterization of Mycobacterium tuberculosis using spoligotyping and 15-loci MIRU-VNTRs reveals phylogeographical specificities of isolates circulating in Guyana and Suriname

In this study we used spoligotyping and 15-loci MIRU-VNTRs for a finer characterization of Mycobacterium tuberculosis strains isolated from patients residing in Guyana (n=74) and Suriname (n=80). The mean age of the patients was 38.5years (36.5 and 40.2years for Guyana vs. Suriname), with a male-to-female sex-ratio of 2.25 for Guyana vs. 4.27 in Suriname. Spoligotyping and 15-loci MIRU-VNTRs led to a total of 41 and 65 different patterns respectively, with an overall clustering rate of 83.8% vs. 68.8%. Combined spoligotyping and VNTR analysis led to the detection of 18 clusters of 2-41 isolates, with an overall clustering of 67.5% and a recent "n-1" transmission rate of 55.8%. Importantly, Guyana was characterized by a significantly higher percentage of clustered isolates than Suriname (79.7% vs. 56.3%; p=0.0019). Three big spoligo/MIRU (SIT/MIT) clusters containing >10 isolates each were shared between the 2 countries, and concerned: T1 sublineage cluster 53/861 (n=41, 37 in Guyana vs. 4 in Suriname); EAI6-BGD1 sublineage cluster 1340/860 (n=16, 3 in Guyana vs. 13 in Suriname); and T1 sublineage cluster 131/146 (n=11, 6 in Guyana vs. 5 in Suriname); as well as 2 smaller clusters of 2 and 3 isolates respectively. However, the relative phylogeographical specificities of strains in circulation as well as a lack of drug-resistance observed among strains from Suriname suggested that trans-border transmission of drug-resistant isolates occurred less frequently than thought. Tracing and interrupting transmission channels of a specific clone (SIT53/15-MIT861) should become a priority in Guyana, not only because it is by far most abundant but also because it accounts for almost half of the drug resistant isolates (n=8/17, 47.1%) in our study, and clustered 5/12 (41.7%) MDR isolates.

Strain classification of Mycobacterium tuberculosis isolates in Brazil based on genotypes obtained by spoligotyping, mycobacterial interspersed repetitive unit typing and the presence of large sequence and single nucleotide polymorphism

Rio de Janeiro is endemic for tuberculosis (TB) and presents the second largest prevalence of the disease in Brazil. Here, we present the bacterial population structure of 218 isolates of Mycobacterium tuberculosis, derived from 186 patients that were diagnosed between January 2008 and December 2009. Genotypes were generated by means of spoligotyping, 24 MIRU-VNTR typing and presence of fbpC¹⁰³, RD^Rio and RD174. The results confirmed earlier data that predominant genotypes in Rio de Janeiro are those of the Euro American Lineages (99%). However, we observed differences between the classification by spoligotyping when comparing to that of 24 MIRU-VNTR typing, being respectively 43.6% vs. 62.4% of LAM, 34.9% vs. 9.6% of T and 18.3% vs. 21.5% of Haarlem. Among isolates classified as LAM by MIRU typing, 28.0% did not present the characteristic spoligotype profile with absence of spacers 21 to 24 and 32 to 36 and we designated these conveniently as “LAM-like”, 79.3% of these presenting the LAM-specific SNP fbpC¹⁰³. The frequency of RD^Rio and RD174 in the LAM strains, as defined both by spoligotyping and 24 MIRU-VNTR loci, were respectively 11% and 15.4%, demonstrating that RD174 is not always a marker for LAM/RD^Rio strains. We conclude that, although spoligotyping alone is a tool for classification of strains of the Euro-American lineage, when combined with MIRU-VNTRs, SNPs and RD typing, it leads to a much better understanding of the bacterial population structure and phylogenetic relationships among strains of M. tuberculosis in regions with high incidence of TB.

Incidence of multidrug-resistant tuberculosis disease in children: systematic review and global estimates

BACKGROUND

Multidrug-resistant tuberculosis threatens to reverse recent reductions in global tuberculosis incidence. Although children younger than 15 years constitute more than 25% of the worldwide population, the global incidence of multidrug-resistant tuberculosis disease in children has never been quantified. We aimed to estimate the regional and global annual incidence of multidrug-resistant tuberculosis in children.

METHODS

We developed two models: one to estimate the setting-specific risk of multidrug-resistant tuberculosis among child cases of tuberculosis, and a second to estimate the setting-specific incidence of tuberculosis disease in children. The model for risk of multidrug-resistant tuberculosis among children with tuberculosis needed a systematic literature review. We multiplied the setting-specific estimates of multidrug-resistant tuberculosis risk and tuberculosis incidence to estimate regional and global incidence of multidrug-resistant tuberculosis disease in children in 2010.

FINDINGS

We identified 3403 papers, of which 97 studies met inclusion criteria for the systematic review of risk of multidrug-resistant tuberculosis. 31 studies reported the risk of multidrug-resistant tuberculosis in both children and treatment-naive adults with tuberculosis and were used for evaluation of the linear association between multidrug-resistant disease risk in these two patient groups. We identified that the setting-specific risk of multidrug-resistant tuberculosis was nearly identical in children and treatment-naive adults with tuberculosis, consistent with the assertion that multidrug-resistant disease in both groups reflects the local risk of transmitted multidrug-resistant tuberculosis. After application of these calculated risks, we estimated that around 999,792 (95% CI 937,877-1,055,414) children developed tuberculosis disease in 2010, of whom 31,948 (25,594-38,663) had multidrug-resistant disease.

INTERPRETATION

Our estimates underscore that many cases of tuberculosis and multidrug-resistant tuberculosis disease are not being detected in children. Future estimates can be refined as more and better tuberculosis data and new diagnostic instruments become available.

FUNDING

US National Institutes of Health, the Helmut Wolfgang Schumann Fellowship in Preventive Medicine at Harvard Medical School, the Norman E Zinberg Fellowship at Harvard Medical School, and the Doris and Howard Hiatt Residency in Global Health Equity and Internal Medicine at the Brigham and Women's Hospital.

[Resistance to first-line drugs and major genotypic lineages of Mycobacterium tuberculosis in the 3 French Department of the Americas: Profiles, evolution, and trends (1995-2011)]

This is the first overview on resistant and multidrug resistant isolates of Mycobacterium tuberculosis circulating in the French Department of the Americas (Guadeloupe, Martinique, and French Guiana) over 17 years (January 1995-December 2011). A total of 1,239 cases were studied: 1,199 new cases (primary and multidrug resistance of 11.8 and 1.6% respectively), and 40 persistent (defined as cases with a previous history of positive culture over 6 months interval and whose spoligotypes remain unchanged), in which significantly higher proportions of resistance to at least isoniazid (22.5%, P = 0.002), rifampicin (20.0%, P < 0.001), and multidrug resistance (17.5%, P < 0.001) were observed as compared to new cases. The 281 spoligotypes obtained showed the presence of five major lineages, T (29.9%), LAM (23.9%), Haarlem (22.1%), EAI (7.1%), and X (6.7%). Two of these lineages, X and LAM, predominate among resistant and multidrug resistant isolates respectively (X: 10.5% of resistant isolates, P = 0.04; LAM: 42.3% of multidrug resistant isolates, P = 0.02). Four of the 19 major spoligo-profiles, corresponding to SIT 20, 64, 45, and 46, were significantly associated with drug resistance. Among them, genotype SIT 20, associated with monoresistance to isoniazid and multidrug resistance, would be actively and persistently in circulation, since 1999, in French Guiana, department in which one may also observe the presence of strains of M. tuberculosis phylogeographically associated to Guiana and Suriname (SIT 131 and SIT 1340).

A systematic follow-up of Mycobacterium tuberculosis drug-resistance and associated genotypic lineages in the French Departments of the Americas over a seventeen-year period

The population of the French Departments of the Americas (FDA) is highly influenced by the intense migratory flows with mainland France and surrounding countries of the Caribbean and Latin America, some of which have high incidence rates of tuberculosis (Haiti: 230/100,000; Guyana: 111/100,000; and Suriname: 145/100,000) and drug resistance. Since the development of drug resistance to conventional antituberculous drugs has a major impact on the treatment success of tuberculosis, we therefore decided to review carefully Mycobacterium tuberculosis drug resistance and associated genotypic lineages in the FDA over a seventeen-year period (January 1995–December 2011). A total of 1239 cases were studied, including 153 drug-resistant and 26 multidrug-resistant- (MDR-) TB cases, representing 12.3% and 2.1% of the TB cases in our study setting. A significantly higher proportion of M. tuberculosis isolates among relapse cases showed drug resistance to isoniazid (22.5%, P = 0.002), rifampicin (20.0%, P < 0.001), or both (MDR-TB, 17.5%; P < 0.001). Determination of spoligotyping based phylogenetic clades showed that among the five major lineages observed—T family (30.1%); Latin-American and Mediterranean (LAM, 23.7%); Haarlem (H, 22.2%); East-African Indian (EAI, 7.2%); and X family (6.5%)—two lineages, X and LAM, were overrepresented in drug-resistant and MDR-TB cases, respectively. Finally, 19 predominant spoligotypes were identified for the 1239 isolates of M. tuberculosis in our study among which 4 were significantly associated with drug resistance corresponding to SIT20/LAM1, SIT64/LAM6, SIT45/H1, and SIT46/undefined lineage.

A first assessment of Mycobacterium tuberculosis genetic diversity and drug-resistance patterns in twelve Caribbean territories

With the exception of some French-speaking islands, data on tuberculosis (TB) in the Caribbean are scarce. In this study, we report a first assessment of genetic diversity of a convenience sample of Mycobacterium tuberculosis strains received from twelve Caribbean territories by spoligotyping and describe their drug-resistance patterns. Of the 480 isolates, 40 (8.3%) isolates showed resistance to at least one anti-TB drug. The proportion of drug-resistant strains was significantly higher in The Bahamas (21.4%; P = 0.02), and Guyana (27.5%; P < 0.0001), while it was significantly lower in Jamaica (2.4%; P = 0.03) than in other countries of the present study. Regarding genetic diversity, 104 distinct spoligotype patterns were observed: 49 corresponded to clustered strains (2 to 93 strains per cluster), while 55 remained unclustered among which 16 patterns were not reported previously. Combining the study results with regional data retrieved from the international SITVIT2 database underlined a connection between frequency of certain M. tuberculosis phylogenetic lineages and the language spoken, suggesting historical (colonial) and ongoing links (trade, tourism, and migratory flows) with European countries with which they shared a common past.

What is AIDS in Guadeloupe? A descriptive and comparative study

Since the pathogen ecology differs between Caribbean regions, specific differences in the most frequent clinical presentations of acquired immunodeficiency syndrome (AIDS) may be expected. We therefore conducted the present retrospective cohort study in order to describe the main AIDS-defining events in Guadeloupe and to compare them with those observed in Metropolitan France and in French Guiana. We discuss the local pathogen ecology, the diagnostic limitations of hospitals in overseas territories and the drivers of the epidemic.

Use of genotyping based clustering to quantify recent tuberculosis transmission in Guadeloupe during a seven years period: analysis of risk factors and access to health care

BACKGROUND

The present study aimed to characterize Mycobacterium tuberculosis population structure and to identify transmission chains and risk factors by prospective molecular typing in conjunction with conventional epidemiological investigations in the French overseas department of Guadeloupe.

METHODS

The study included all the culture-positive TB cases (1 clinical isolate per patient; n = 129) diagnosed between a seven year period (April 4th, 1999 to December 31st, 2005). Prospective molecular typing was performed using spoligotyping and VNTRs, and a subset of 44 M. tuberculosis isolates found to be clustered was retrospectively typed using 12-loci MIRUs. Data were compared using the SITVIT2 database, followed by analysis of risk factors in function of clustering of the isolates and available demographic and socioeconomic data.

RESULTS

The study sample was characterized by a majority of new cases (87.4%); a moderate proportion of drug-resistance (7.8%); a high level of immigration (51.2% foreign-born) originating from high TB/HIV incidence neighboring islands such as Haiti or Dominican Republic; lower socioeconomic conditions (70.7% of jobless, average income 824 EUR/month); and a significantly higher proportion of TB/HIV co-infected cases (38.2% vs. 8.5%; p < 0.001), and extrapulmonary disease (18.2% vs. 4.8%; p < 0.02) among migrants as compared to French patients. The study revealed an important delay in access to healthcare with a median delay of 74.5 days between the 1st symptoms and clinical suspicion of TB. Prospective molecular typing based on spoligotyping and 5-loci VNTRs showed that evolutionary recent Euro-American lineages predominated in Guadeloupe (91.5% of isolates). In conjunction with epidemiological data, it allowed to estimate a recent transmission rate of 18.6%, which was close to the rate of 16.7% estimated using retrospective 12-loci MIRU typing. Although a higher proportion of cases in older age-group were apparently linked to reactivation; univariate analysis of risk factors did not allow pinpointing specific risk factors for a patient to belong to a TB transmission group.

CONCLUSIONS

Ongoing TB transmission in the insular, low TB-incidence setting of Guadeloupe can be defined as follows: (i) a significant proportion of imported cases of the disease from neighboring islands; (ii) significantly higher TB/HIV coinfection among foreign-born cases; and, (iii) a higher proportion of cases affecting older age-group among French patients due to reactivation. This study emphasizes the need for universal typing using spoligotyping and 15-loci MIRUs in prospective studies.

Isoniazid-resistant tuberculosis in children: a systematic review

BACKGROUND

Isoniazid resistance is an obstacle to the treatment of tuberculosis disease and latent tuberculosis infection in children. We aim to summarize the literature describing the risk of isoniazid-resistant tuberculosis among children with tuberculosis disease.

METHODS

We did a systematic review of published reports of children with tuberculosis disease who had isolates tested for susceptibility to isoniazid. We searched PubMed, Embase and LILACS online databases up to January 12, 2012.

RESULTS

Our search identified 3403 citations, of which 95 studies met inclusion criteria. These studies evaluated 8351 children with tuberculosis disease for resistance to isoniazid. The median proportion of children found to have isoniazid-resistant strains was 8%; the distribution was right-skewed (25th percentile: 0% and 75th percentile: 18%).

CONCLUSIONS

High proportions of isoniazid resistance among pediatric tuberculosis patients have been reported in many settings suggesting that diagnostics detecting only rifampin resistance are insufficient to guide appropriate treatment in this population. Many children are likely receiving substandard tuberculosis treatment with empirical isoniazid-based regimens, and treating latent tuberculosis infection with isoniazid may not be effective in large numbers of children. Work is needed urgently to identify effective regimens for the treatment of children sick with or exposed to isoniazid-resistant tuberculosis and to better understand the scope of this problem.

First insights into the phylogenetic diversity of Mycobacterium tuberculosis in Nepal

Background

Tuberculosis (TB) is a major public health problem in Nepal. Strain variation in Mycobacterium tuberculosis may influence the outcome of TB infection and disease. To date, the phylogenetic diversity of M. tuberculosis in Nepal is unknown.

Methods and Findings

We analyzed 261 M. tuberculosis isolates recovered from pulmonary TB patients recruited between August 2009 and August 2010 in Nepal. M. tuberculosis lineages were determined by single nucleotide polymorphisms (SNP) typing and spoligotyping. Drug resistance was determined by sequencing the hot spot regions of the relevant target genes. Overall, 164 (62.8%) TB patients were new, and 97 (37.2%) were previously treated. Any drug resistance was detected in 50 (19.2%) isolates, and 16 (6.1%) were multidrug-resistant. The most frequent M. tuberculosis lineage was Lineage 3 (CAS/Delhi) with 106 isolates (40.6%), followed by Lineage 2 (East-Asian lineage, includes Beijing genotype) with 84 isolates (32.2%), Lineage 4 (Euro-American lineage) with 41 (15.7%) isolates, and Lineage 1 (Indo-Oceanic lineage) with 30 isolates (11.5%). Based on spoligotyping, we found 45 different spoligotyping patterns that were previously described. The Beijing (83 isolates, 31.8%) and CAS spoligotype (52, 19.9%) were the dominant spoligotypes. A total of 36 (13.8%) isolates could not be assigned to any known spoligotyping pattern. Lineage 2 was associated with female sex (adjusted odds ratio [aOR] 2.58, 95% confidence interval [95% CI] 1.42–4.67, p = 0.002), and any drug resistance (aOR 2.79; 95% CI 1.43–5.45; p = 0.002). We found no evidence for an association of Lineage 2 with age or BCG vaccination status.

Conclusions

We found a large genetic diversity of M. tuberculosis in Nepal with representation of all four major lineages. Lineages 3 and 2 were dominating. Lineage 2 was associated with clinical characteristics. This study fills an important gap on the map of the M. tuberculosis genetic diversity in the Asian region.

Molecular epidemiology of Mycobacterium tuberculosis, Buenos Aires, Argentina

To analyze the molecular epidemiology of Mycobacterium tuberculosis strains at a hospital in Buenos Aires, Argentina, and mutations related to multidrug-resistant and extensively drug-resistant tuberculosis, we conducted a prospective case-control study. Our findings reinforce the value of incorporating already standardized molecular methods for rapidly detecting resistance.

Finer snapshot of circulating Mycobacterium tuberculosis genotypes in Guadeloupe, Martinique, and French Guiana

This study shows the benefit of spoligotyping coupled to mycobacterial interspersed repetitive-unit (MIRU) typing to pinpoint circulating Mycobacterium tuberculosis genotypes in Guadeloupe, Martinique, and French Guiana. We hereby propose reduced 4-locus and 6-locus subsets for LAM and Haarlem lineage strains that predominate in South America and the Caribbean, retaining 99.35% and 99.64% of the total discriminatory power of the 12-locus scheme, respectively.

Spoligotype profile of Mycobacterium tuberculosis complex strains from HIV-positive and -negative patients in Nigeria: a comparative analysis

We ran a comparative analysis of all patients for whom a positive culture of Mycobacterium tuberculosis complex was available between April 2004 and October 2005 and whose HIV serology results were known, with spoligotyping results (n = 163) split into 49 HIV-positive patients and 114 HIV-negative patients. Spoligotype international type 373 (SIT373) (T1 lineage), which was highly prevalent among the HIV(+) patients, was totally absent from the HIV(-) population, suggesting that we had a specific clone affecting nearly 1/3 of all HIV-tuberculosis (TB)-coinfected patients. Among the LAM10-CAM sublineage strains, we had only a single strain of SIT403 among HIV(-) patients (0.88%), as opposed to 12.25% of the HIV(+) population (χ(2) = 10.77; P < 0.01), indicating a strong association between the strain and the HIV(+) population. The LAM10-CAM lineage spoligotype SIT61 was prevalent among the 2 subsets (37.72% in HIV(-) versus 12.24% in HIV(+) populations), though, with a significant difference between the 2 groups (χ(2) = 10.53; P < 0.01). However, there was no significant difference for SIT53 (T1 lineage) in the 2 subsets: 6.14 versus 8.2% (χ(2) = 0.22; P > 0.05). A total of 7/49, or 14.3%, other SITs among HIV(+) patients were not found among the HIV(-) patients. When added to the most prevalent SIT among HIV(+) patients (SIT373; n = 16), 23/49, or 47%, isolates among HIV-TB-coinfected patients were unique. We conclude that further studies should be carried out to investigate the evolution of these genotypes and others in the emergence of multidrug resistance and control of tuberculosis in Nigeria.

Spoligotype-based comparative population structure analysis of multidrug-resistant and isoniazid-monoresistant Mycobacterium tuberculosis complex clinical isolates in Poland

The spoligotyping-based population structure of multidrug-resistant (MDR) Mycobacterium tuberculosis strains isolated in Poland (n = 46), representing all culture-positive MDR tuberculosis (MDR-TB) cases, was compared to that of isoniazid (INH)-monoresistant strains (n = 71) isolated in 2004. The latter data set from a previous study (E. Augustynowicz-Kopeć, T. Jagielski, and Z. Zwolska, J. Clin. Microbiol. 2008, 46:4041-4044) represented 87% of all INH-monoresistant strains. The clustering rates and genotypic-diversity indexes for the 2 subpopulations were not significantly different (P = 0.05). The results were entered in the SITVIT2 database to assign specific shared type designations, corresponding genotypic lineages, and geographical distributions and compared to available data from neighboring countries (Germany, n = 704; Czech Republic, n = 530; Sweden, n = 379; Kaliningrad, Russia, n = 90) and strains from previous studies in Poland (n = 317). MDR strains resulted in 27 patterns (20 unique strains within the study and 7 clusters containing 2 to 6 isolates per cluster with a clustering rate of 56.5%) and belonged to the following genotypic lineages: ill-defined T family (28.3%), Haarlem (17.4%), Latin American and Mediterranean (LAM) (13%), Beijing (8.7%), S family (4.35%), and the X clade (2.17%). Comparison of the genetic structure of the MDR strains with that of INH-monoresistant strains showed that a total of 9 patterns were shared by both groups; these represented 1/3 of the MDR strains and 2/3 of the INH-monoresistant strains. Interestingly, 76.1% of the MDR isolates and 71.8% of the INH-resistant isolates yielded spoligotypes that were previously reported from Poland. The observation that nearly half of the spoligotypes identified among both MDR (48.1%) and INH-monoresistant (43.3%) M. tuberculosis isolates were present in Poland's neighboring countries suggested that a significant proportion of MDR and INH-resistant TB cases in Poland were caused by strains actively circulating in Poland or its neighbors. Our results corroborate the leading role of the T and Haarlem genotypes in the epidemiology of drug-resistant TB in Poland. Nevertheless, the LAM and Beijing family strains that infected, correspondingly, 13% and 9% of patients with MDR-TB were absent among the strains from patients with INH-monoresistant TB, suggesting that a proportion of MDR-TB cases in Poland are due to ongoing transmission of MDR clones exhibiting specific genotypes. Study of the population genetic relationships between MDR and INH-monoresistant strains by drawing minimum spanning trees showed that ill-defined T1 sublineage strains (1/3 of all INH-monoresistant strains), represented by its prototype, SIT53, constituted the central node of the tree, followed by strains belonging to the well-defined H3, H1, and S subgroups. However, the MDR group, in addition, contained LAM (n = 6) and Beijing (n = 4) lineage isolates. With the exception of the 4 Beijing lineage strains in the latter group and a single orphan isolate in the INH-monoresistant group, none of the remaining 112/117 isolates belonged to principal genetic group 1 (PGG1) in our study. Given the high rate of clustering and the near absence of immigrants in the study, the persistence of MDR-TB in Poland seems to result from active transmission of MDR strains within the autochthonous population, the bulk of it caused by evolutionarily recent tubercle bacilli.

First insight into Mycobacterium tuberculosis epidemiology and genetic diversity in Trinidad and Tobago

This report is based on a 1-year recruitment of all of the culture-positive Mycobacterium tuberculosis cases in Trinidad and Tobago (n = 132). The study population was characterized by a high male-to-female sex ratio of 4 and a human immunodeficiency virus-tuberculosis (TB) coinfection rate of 30%. It mainly occurred among African descendants, who represent 37.5% of the total population but 69.7% of all TB cases (P < 0.001). Spoligotyping resulted in 25 different patterns and 12 clusters (2 to 74 strains per cluster), with the predominance of a highly conserved spoligotype international type clone, SIT566.

Use of cluster-graphs from spoligotyping data to study genotype similarities and a comparison of three indices to quantify recent tuberculosis transmission among culture positive cases in French Guiana during a eight year period

Background

French Guiana has the highest tuberculosis (TB) burden among all French departments, with a strong increase in the TB incidence over the last few years. It is now uncertain how best to explain this incidence. The objective of this study was to compare three different methods evaluating the extent of recent TB transmission in French Guiana.

Methods

We conducted a population-based molecular epidemiology study of tuberculosis in French Guiana based on culture-positive TB strains (1996 to 2003, n = 344) to define molecular relatedness between isolates, i.e. potential transmission events. Phylogenetic relationships were inferred by comparing two methods: a "cluster-graph" method based on spoligotyping results, and a minimum spanning tree method based on both spoligotyping and variable number of tandem DNA repeats (VNTR). Furthermore, three indices attempting to reflect the extent of recent TB transmission (RTIn, RTIn-1 and TMI) were compared.

Results

Molecular analyses showed a total amount of 120 different spoligotyping patterns and 273 clinical isolates (79.4%) that were grouped in 49 clusters. The comparison of spoligotypes from French Guiana with an international spoligotype database (SpolDB4) showed that the majority of isolates belonged to major clades of M. tuberculosis (Haarlem, 22.6%; Latin American-Mediterranean, 23.3%; and T, 32.6%). Indices designed to quantify transmission of tuberculosis gave the following values: RTIn = 0.794, RTIn-1 = 0.651, and TMI = 0.146.

Conclusion

Our data showed a high number of Mycobacterium tuberculosis clusters, suggesting a high level of recent TB transmission, nonetheless an estimation of transmission rate taking into account cluster size and mutation rate of genetic markers showed a low ongoing transmission rate (14.6%). Our results indicate an endemic mode of TB transmission in French Guiana, with both resurgence of old spatially restricted genotypes, and a significant importation of new TB genotypes by migration of TB infected persons from neighgouring high-incidence countries.

Molecular characterization of Mycobacterium tuberculosis isolates from different regions of Bulgaria

Mycobacterium tuberculosis isolates from different regions of Bulgaria were studied by a variety of molecular typing tools. Based on spacer oligonucleotide typing (spoligotyping), the 113 strains were subdivided into 35 spoligotypes: 5 unique profiles and 15 profiles shared by two to 29 strains; the Hunter-Gaston diversity index (HGI) was 0.9. Comparison with the international database SITVIT2 at the Institut Pasteur de Guadeloupe showed the presence of two globally distributed shared types, ST53 (25.7%) and ST47 (6.2%). Nineteen (16.8%) and six (5.3%) strains belonged to the ST125 (LAM/S subfamily) and ST41 (LAM7_TUR subfamily) types described in SITVIT2 as ubiquitous/rare and ubiquitous/common types, respectively. Seven spoligoprofiles (12 strains) were not found in the database; two of them constituted new shared types. The Beijing genotype strains were not found in the studied collection in spite of close contacts with Russia in the recent and historical past. Additional subtyping by IS6110-restriction fragment length polymorphism (RFLP) and 12-locus mycobacterial interspersed repetitive unit (MIRU)-variable number of tandem repeat analyses were performed within selected spoligotypes. In particular, MIRU typing showed better discrimination within ST125 than IS6110-RFLP typing (HGI = 0.83 versus 0.39). A high gradient for ST125 in Bulgaria compared to its negligible presence in the global database and neighboring countries leads us to suggest a Bulgarian phylogeographic specificity of this spoligotype. To conclude, this first study of the Bulgarian M. tuberculosis population demonstrated its heterogeneity and predominance of several worldwide-distributed and Balkan-specific spoligotypes.

Discovery of a novel Mycobacterium tuberculosis lineage that is a major cause of tuberculosis in Rio de Janeiro, Brazil

The current study evaluated Mycobacterium tuberculosis isolates from Rio de Janeiro, Brazil, for genomic deletions. One locus in our panel of PCR targets failed to amplify in approximately 30% of strains. A single novel long sequence polymorphism (>26.3 kb) was characterized and designated RD(Rio). Homologous recombination between two similar protein-coding genes is proposed as the mechanism for deleting or modifying 10 genes, including two potentially immunogenic PPE proteins. The flanking regions of the RD(Rio) locus were identical in all strains bearing the deletion. Genetic testing by principal genetic group, spoligotyping, variable-number tandem repeats of mycobacterial interspersed repetitive units (MIRU-VNTR), and IS6110-based restriction fragment length polymorphism analysis cumulatively support the idea that RD(Rio) strains are derived from a common ancestor belonging solely to the Latin American-Mediterranean spoligotype family. The RD(Rio) lineage is therefore the predominant clade causing tuberculosis (TB) in Rio de Janeiro and, as indicated by genotypic clustering in MIRU-VNTR analysis, the most significant source of recent transmission. Limited retrospective reviews of bacteriological and patient records showed a lack of association with multidrug resistance or specific risk factors for TB. However, trends in the data did suggest that RD(Rio) strains may cause a form of TB with a distinct clinical presentation. Overall, the high prevalence of this genotype may be related to enhanced virulence, transmissibility, and/or specific adaptation to a Euro-Latin American host population. The identification of RD(Rio) strains outside of Brazil points to the ongoing intercontinental dissemination of this important genotype. Further studies are needed to determine the differential strain-specific features, pathobiology, and worldwide prevalence of RD(Rio) M. tuberculosis.

Tuberculosis transmission in a high incidence area: a retrospective molecular epidemiological study of Mycobacterium tuberculosis in Casablanca, Morocco

Like in most developing countries, tuberculosis represents a major public health problem in Morocco. This paper describes the first study combining molecular and conventional epidemiology of tuberculosis in Casablanca, the economic capital of this country. Molecular fingerprinting of the genomic DNA recovered from cultures of sputum of 150 patients was performed by MIRU-VNTR. This molecular marker revealed that 53.1% of the total cases were clustered. These cases were classified into 23 clusters ranging in size from 2 to 13 patients, suggesting a rate of 37% of recent transmission in the sample under study. In a multivariate analysis, there were no independent predictors of clustering. However, the clinical form was associated with drug resistance (odds ratio=9.9; P value=0.0006). The phylogenetic analysis showed that the heterogeneity found in this population includes also the members from a same patient family, and that the 2 major families distributed in Casablanca were the Latin-American-Mediterranean (LAM) and Haarlem families. All the results of this work allow to understand better the tuberculosis transmission in Casablanca, and suggest that different clones of M. tuberculosis seem to circulate in this city, and that the reactivation of latent infections would be mainly responsible for the endemic situation of this disease. These findings indicate also that the transmission of TB in Morocco is not optimally controlled, and that efforts for control strategies should be sustained in all developing countries where the incidence of TB is high and still raising.

Molecular characterisation of Mycobacterium tuberculosis isolates in the First National Survey of Anti-tuberculosis Drug Resistance from Venezuela

Background

Molecular typing of Mycobacterium tuberculosis strains has become a valuable tool in the epidemiology of tuberculosis (TB) by allowing detection of outbreaks, tracking of epidemics, identification of genotypes and transmission events among patients who would have remained undetected by conventional contact investigation. This is the first genetic biodiversity study of M. tuberculosis in Venezuela. Thus, we investigated the genetic patterns of strains isolated in the first survey of anti-tuberculosis drug-resistance realised as part of the Global Project of Anti-tuberculosis Drug Resistance Surveillance (WHO/IUATLD).

Results

Clinical isolates (670/873) were genotyped by spoligotyping. The results were compared with the international spoligotyping database (SpolDB4). Multidrug resistant (MDR) strains (14/18) were also analysed by IS6110-RFLP assays, and resistance to isoniazid and rifampicin was characterised.

Spoligotyping grouped 82% (548/670) of the strains into 59 clusters. Twenty new spoligotypes (SITs) specific to Venezuela were identified. Eight new inter-regional clusters were created. The Beijing genotype was not found. The genetic network shows that the Latin American and Mediterranean family constitutes the backbone of the genetic TB population-structure in Venezuela, responsible of >60% of total TB cases studied. MDR was 0.5% in never treated patients and 13.5% in previously treated patients. Mutations in rpoB gene and katG genes were detected in 64% and 43% of the MDR strains, respectively.

Two clusters were found to be identical by the four different analysis methods, presumably representing cases of recent transmission of MDR tuberculosis.

Conclusion

This study gives a first overview of the M. tuberculosis strains circulating in Venezuela during the first survey of anti-tuberculosis drug-resistance. It may aid in the creation of a national database that will be a valuable support for further studies.