Genomic analysis of globally diverse Mycobacterium tuberculosis strains provides insights into the emergence and spread of multidrug resistance.

Multidrug-resistant tuberculosis (MDR-TB), caused by drug-resistant strains of Mycobacterium tuberculosis, is an increasingly serious problem worldwide. Here we examined a data set of whole-genome sequences from 5,310 M. tuberculosis isolates from five continents. Despite the great diversity of these isolates with respect to geographical point of isolation, genetic background and drug resistance, the patterns for the emergence of drug resistance were conserved globally. We have identified harbinger mutations that often precede multidrug resistance. In particular, the katG mutation encoding p.Ser315Thr, which confers resistance to isoniazid, overwhelmingly arose before mutations that conferred rifampicin resistance across all of the lineages, geographical regions and time periods. Therefore, molecular diagnostics that include markers for rifampicin resistance alone will be insufficient to identify pre-MDR strains. Incorporating knowledge of polymorphisms that occur before the emergence of multidrug resistance, particularly katG p.Ser315Thr, into molecular diagnostics should enable targeted treatment of patients with pre-MDR-TB to prevent further development of MDR-TB.

Whole-Genome Sequencing of Mycobacterium tuberculosis Provides Insight into the Evolution and Genetic Composition of Drug-Resistant Tuberculosis in Belarus.

The emergence and spread of drug-resistant Mycobacterium tuberculosis (DR-TB) are critical global health issues. Eastern Europe has some of the highest incidences of DR-TB, particularly multidrug-resistant (MDR) and extensively drug-resistant (XDR) TB. To better understand the genetic composition and evolution of MDR- and XDR-TB in the region, we sequenced and analyzed the genomes of 138 M. tuberculosis isolates from 97 patients sampled between 2010 and 2013 in Minsk, Belarus. MDR and XDR-TB isolates were significantly more likely to belong to the Beijing lineage than to the Euro-American lineage, and known resistance-conferring loci accounted for the majority of phenotypic resistance to first- and second-line drugs in MDR and XDR-TB. Using a phylogenomic approach, we estimated that the majority of MDR-TB was due to the recent transmission of already-resistant M. tuberculosis strains rather than repeated de novo evolution of resistance within patients, while XDR-TB was acquired through both routes. Longitudinal sampling of M. tuberculosis from 34 patients with treatment failure showed that most strains persisted genetically unchanged during treatment or acquired resistance to fluoroquinolones. HIV+ patients were significantly more likely to have multiple infections over time than HIV- patients, highlighting a specific need for careful infection control in these patients. These data provide a better understanding of the genomic composition, transmission, and evolution of MDR- and XDR-TB in Belarus and will enable improved diagnostics, treatment protocols, and prognostic decision-making.

Diagnostic Performance of the New Version (v2.0) of GenoType MTBDRsl Assay for Detection of Resistance to Fluoroquinolones and Second-Line Injectable Drugs: a Multicenter Study.

Resistance to fluoroquinolones (FLQ) and second-line injectable drugs (SLID) is steadily increasing, especially in eastern European countries, posing a serious threat to effective tuberculosis (TB) infection control and adequate patient management. The availability of rapid molecular tests for the detection of extensively drug-resistant TB (XDR-TB) is critical in areas with high rates of multidrug-resistant TB (MDR-TB) and XDR-TB and limited conventional drug susceptibility testing (DST) capacity. We conducted a multicenter study to evaluate the performance of the new version (v2.0) of the Genotype MTBDRsl assay compared to phenotypic DST and sequencing on a panel of 228 Mycobacterium tuberculosis isolates and 231 smear-positive clinical specimens. The inclusion of probes for the detection of mutations in the eis promoter region in the MTBDRsl v2.0 test resulted in a higher sensitivity for detection of kanamycin resistance for both direct and indirect testing (96% and 95.4%, respectively) than that seen with the original version of the assay, whereas the test sensitivities for detection of FLQ resistance remained unchanged (93% and 83.6% for direct and indirect testing, respectively). Moreover, MTBDRsl v2.0 showed better performance characteristics than v1.0 for the detection of XDR-TB, with high specificity and sensitivities of 81.8% and 80.4% for direct and indirect testing, respectively. MTBDRsl v2.0 thus represents a reliable test for the rapid detection of resistance to second-line drugs and a useful screening tool to guide the initiation of appropriate MDR-TB treatment.

Multidrug-resistant tuberculosis in Belarus: the size of the problem and associated risk factors.

OBJECTIVE: To assess the problem of multidrug-resistant tuberculosis (MDR-TB) throughout Belarus and investigate the associated risk factors. METHODS: In a nationwide survey in 2010-2011, 1420 tuberculosis (TB) patients were screened and 934 new and 410 previously treated cases of TB were found to meet the inclusion criteria. Isolates of Mycobacterium tuberculosis from each eligible patient were tested for susceptibility to anti-TB drugs. Sociobehavioural information was gathered in interviews based on a structured questionnaire. FINDINGS: MDR-TB was found in 32.3% and 75.6% of the new and previously treated patients, respectively, and, 11.9% of the 612 patients found to have MDR-TB had extensively drug-resistant TB (XDR-TB). A history of previous treatment for TB was the strongest independent risk factor for MDR-TB (odds ratio, OR: 6.1; 95% confidence interval, CI: 4.8-7.7). The other independent risk factors were human immunodeficiency virus (HIV) infection (OR: 2.2; 95% CI: 1.4-3.5), age < 35 years (OR: 1.4; 95% CI: 1.0-1.8), history of imprisonment (OR: 1.5; 95% CI: 1.1-2.0), disability sufficient to prevent work (OR: 1.9; 95% CI: 1.2-3.0), alcohol abuse (OR: 1.3; 95% CI: 1.0-1.8) and smoking (OR: 1.5; 95% CI: 1.1-2.0). CONCLUSION: MDR-TB is very common among TB patients throughout Belarus. The numerous risk factors identified for MDR-TB and the convergence of the epidemics of MDR-TB and HIV infection call not only for stronger collaboration between TB and HIV control programmes, but also for the implementation of innovative measures to accelerate the detection of TB resistance and improve treatment adherence.

Résumé OBJECTIF: Évaluer le problème de la tuberculose multirésistante (TB-MR) sur le territoire biélorusse et explorer les facteurs de risque associés. MÉTHODES: Au cours d'une enquête nationale menée en 2010-2011, 1420 cas de tuberculose (TB) ont été dépistés et 934 cas nouveaux ainsi que 410 cas précédemment traités ont été jugés conformes aux critères d'inclusion. Des isolats de Mycobacterium tuberculosis provenant de chaque patient admissible ont été testés pour leur sensibilité envers les médicaments antituberculeux. Des informations sociocomportementales ont été recueillies lors d'entretiens basés sur un questionnaire structuré. RÉSULTATS: La TB-MR a été détectée dans respectivement 32,3% et 75,6% des cas nouveaux et des cas traités antérieurement, et 11,9% des 612 patients porteurs de la TB-MR présentaient une forme de tuberculose ultrarésistante (TB-UR). Un historique de traitement antérieur pour la TB représentait le principal facteur de risque indépendant pour la TB-MR (rapport des cotes, RC: 6,1; intervalle de confiance à 95%, IC: 4,8 à 7,7). Les autres facteurs de risque indépendants comprenaient l'infection par le virus d'immunodéficience humaine (VIH) (RC: 2,2; IC à 95%: 1,4 à 3,5), l'âge <35 ans (RC: 1,4 ; IC à 95%: 1,0 à 1,8), un historique d'emprisonnement (RC: 1,5; IC à 95%: 1,1 à 2,0), une invalidité suffisante pour empêcher le travail (RC: 1,9 ; IC à 95%: 1,2 à 3,0), l'alcoolisme (RC: 1,3; IC à 95%: 1,0 à 1,8) et le tabagisme (RC: 1,5; IC à 95%: 1,1 à 2,0). CONCLUSION: La TB-MR est très fréquente chez les patients atteints de tuberculose en Bélarus. Les nombreux facteurs de risque identifiés pour la TB-MR et la convergence entre l'épidémie de TB-MR et l'infection par le VIH exigent non seulement de renforcer la collaboration entre les programmes antituberculeux et de lutte contre le VIH, mais aussi la mise en œuvre de mesures innovantes pour accélérer la détection de la résistance à la tuberculose et améliorer l'observance du traitement.

Resumen OBJETIVO: Evaluar el problema de la tuberculosis multirresistente (TB-MR) en Bielorrusia e investigar los factores de riesgo asociados. MÉTODOS: En una encuesta a nivel nacional llevada a cabo entre 2010 y 2011, se evaluó a 1420 pacientes con tuberculosis (TB) y se consideró que 934 nuevos casos de TB y 410 casos de TB previamente tratados reunían los criterios de inclusión. Se analizaron cepas de Mycobacterium tuberculosis de cada paciente elegible con el fin de determinar la susceptibilidad a los fármacos antituberculosos. Se recopiló información socioconductual mediante entrevistas basadas en un cuestionario estructurado. RESULTADOS: Se detectó TB-MR en el 32,3% y el 75,6% de los pacientes de nuevo diagnóstico y tratados previamente, respectivamente, y se observó que el 11,9% de los 612 pacientes con TB-MR presentaba tuberculosis ultrarresistente (TB-XR). Los antecedentes de tratamiento previo de la TB resultaron ser el factor de riesgo independiente que más predispone a sufrir TB-MR (razón de posibilidades, OR: 6,1; intervalo de confianza del 95%, IC: 4,8­7,7). Los demás factores de riesgo independientes fueron el virus de la inmunodeficiencia humana (VIH) (OR: 2,2; IC del 95%: 1,4­3,5), edad < 35 años (OR: 1,4; IC del 95%: 1,0­1,8), antecedentes de encarcelamiento (OR: 1,5; IC del 95%: 1,1­2,0), incapacidad suficiente para impedir el trabajo (OR: 1,9; IC del 95%: 1,2­3,0), alcoholismo (OR: 1,3; IC del 95%: 1,0­1,8) y tabaquismo (OR: 1,5; IC del 95%: 1,1­2,0). CONCLUSIÓN: La TB.MR es muy frecuente entre los pacientes con tuberculosis en Bielorrusia. Los numerosos factores de riesgo identificados para la TB-MR, unidos a la convergencia de las epidemias de TB-MR y la infección por el VIH, exigen no solo una mayor colaboración entre los programas de control de la TB y del VIH, sino también la aplicación de medidas innovadoras destinadas a acelerar la detección de la resistencia a la TB y mejorar el cumplimiento terapéutico.

Multidrug-resistant Myobacterium tuberculosis caused by the Beijing genotype and a specific T1 genotype clone (SIT No. 266) is widely transmitted in Minsk.

SETTING: This study was performed in the city of Minsk in Belarus, where a very severe problem with MDR-TB was demonstrated in a recent drug resistant survey. OBJECTIVE: The aim of this study was to use molecular typing of MDR and pan-susceptible clinical isolates of Mycobacterium tuberculosis to increase the understanding of the transmission patterns and possible differences between the strains causing susceptible and drug-resistant tuberculosis. STUDY POPULATION AND METHODS: Consecutive isolates from pulmonary TB patients in Minsk were collected at the Belarusian National Reference Laboratory. Isolates found to be either pan-susceptible or MDR were included in the study, which totally comprised 81 MDR and 82 pan-susceptible clinical isolates. All isolates were characterized by spoligotyping. The major clusters were characterized using sequencing of the pncA gene. RESULTS: Three out of four MDR cases were caused by one out of two drug-resistant clones of M. tuberculosis belonging to the Beijing and T1 genotypes, respectively. A single T1 clone, SIT No. 266, found exclusively in the MDR cohort, was shown to cause no less than 30% of all MDR-TB cases. DISCUSSION: The findings indicate that the major cause of MDR-TB in Minsk is an ongoing transmission of certain already resistant M. tuberculosis strains. CONCLUSION: The significant transmission of MDR-TB in Minsk underlines the urgent need for strengthened infection control measures to limit the transmission in order to better control MDR-TB.

Alarming levels of drug-resistant tuberculosis in Belarus: results of a survey in Minsk.

Resistance to anti-tuberculosis (TB) medicines is a major public health threat in most countries of the former Soviet Union. As no representative and quality-assured information on the magnitude of this problem existed in Belarus, a survey was conducted in the capital city of Minsk. Between November 2009 and December 2010, 156 consecutively diagnosed new and 68 previously treated culture-positive TB patients residing in Minsk were enrolled in the survey. Mycobacterium tuberculosis isolates were obtained from each patient and tested for susceptibility to first- and second-line anti-TB drugs. Multidrug-resistant (MDR)-TB was found in 35.3% (95% CI 27.7-42.8) of new patients and 76.5% (95% CI 66.1-86.8) of those previously treated. Overall, nearly one in two patients enrolled had MDR-TB. Extensively drug-resistant TB was reported in 15 of the 107 MDR-TB patients (14.0%, 95% CI 7.3-20.7). Patients <35 yrs of age have shown a two times higher odds ratio of multidrug-resistant TB than those aged >35 yrs. The findings of this survey in Minsk city are alarming and represent the highest proportions of MDR-TB ever recorded in the world. This study greatly contributes to the understanding of the burden of drug-resistant TB in urban areas of Belarus.