Extensive transmission of Mycobacterium tuberculosis from 9 year old child with pulmonary tuberculosis and negative sputum smear

Paranjothy, Shantini; Eisenhut, Michael; Lilley, M; Bracebridge, Sam; Abubakar, Ibrahim; Mulla, Rohinton; Lack, K.; Chalkley, D.; Howard, Julia; Thomas, Sandra H.; McEvoy, M

doi:10.1136/bmj.a1184

Cited by 29 publications

(15 citation statements)

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“…Molecular strain typing (genotyping) has contributed significantly to the understanding of TB epidemiology and has helped to improve TB control by providing information on transmission dynamics [5], determining the importance of reactivation versus exogenous reinfection [6], investigating/confirming outbreaks [7], confirmation of laboratory cross contamination [8] and to identify the clonal spread of successful clones, including multi-drug-resistant ones [9]. Furthermore, molecular typing has revealed that the MTBC has a diverse population structure with manifold lineages that show large differences in their geographical occurrence and, also, in their pathobiological properties e.g.…”

Section: Introductionmentioning

confidence: 99%

Molecular epidemiology and transmission dynamics of Mycobacterium tuberculosis in Northwest Ethiopia: new phylogenetic lineages found in Northwest Ethiopia

et al. 2013

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BackgroundAlthough Ethiopia ranks seventh among the world’s 22 high-burden tuberculosis (TB) countries, little is known about strain diversity and transmission. In this study, we present the first in-depth analysis of the population structure and transmission dynamics of Mycobacterium tuberculosis strains from Northwest Ethiopia.MethodsIn the present study, 244 M. tuberculosis isolates where analysed by mycobacterial interspersed repetitive unit - variable number tandem repeat 24-loci typing and spoligotyping methods to determine phylogenetic lineages and perform cluster analysis. Clusters of strains with identical genotyping patterns were considered as an indicator for the recent transmission.ResultsOf 244 isolates, 59.0% were classified into nine previously described lineages: Dehli/CAS (38.9%), Haarlem (8.6%), Ural (3.3%), LAM (3.3%), TUR (2.0%), X-type (1.2%), S-type (0.8%), Beijing (0.4%) and Uganda II (0.4%). Interestingly, 31.6% of the strains were grouped into four new lineages and were named as Ethiopia_3 (13.1%), Ethiopia_1 (7.8%), Ethiopia_H37Rv like (7.0%) and Ethiopia_2 (3.7%) lineages. The remaining 9.4% of the isolates could not be assigned to the known or new lineages. Overall, 45.1% of the isolates were grouped in clusters, indicating a high rate of recent transmission.ConclusionsThis study confirms a highly diverse M. tuberculosis population structure, the presence of new phylogenetic lineages and a predominance of the Dehli/CAS lineage in Northwest Ethiopia. The high rate of recent transmission indicates defects of the TB control program in Northwest Ethiopia. This emphasizes the importance of strengthening laboratory diagnosis of TB, intensified case finding and treatment of TB patients to interrupt the chain of transmission.

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Section: Introductionmentioning

confidence: 99%

Molecular epidemiology and transmission dynamics of Mycobacterium tuberculosis in Northwest Ethiopia: new phylogenetic lineages found in Northwest Ethiopia

et al. 2013

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“…Molecular strain typing (genotyping) has significantly contributed worldwide to the understanding of TB epidemiology and transmission dynamics (15,16), by confirming outbreaks (17) and identifying the clonal spread of successful strains, including MDR strains (18,19). Furthermore, molecular typing has shown that the Mycobacterium tuberculosis complex (MTBc) has a diverse population structure, being composed of seven lineages of human importance, subdivided into families (20,21) that differ not only in their geographical occurrence but also in their drug resistance profiles (19,22).…”

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confidence: 99%

Predominant Mycobacterium tuberculosis Families and High Rates of Recent Transmission among New Cases Are Not Associated with Primary Multidrug Resistance in Lima, Peru

et al. 2015

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T uberculosis (TB) is among the top 10 causes of death in the global ranking (1). Although Peru accounts for only 3% of the population of the Americas, it has 9.5% of the region's TB cases. According to the World Health Organization (WHO), 21,916 new cases of pulmonary TB were reported in Peru between January and November 2013 (2). Urban areas are more affected, with 59% of all Peruvian TB cases, 82% of multidrug-resistant (MDR) TB cases, and 93% of extensively drug-resistant (XDR) TB cases occurring in Lima. Within the capital area, TB cases are heterogeneously distributed. The most affected districts are located in the northeast and together represent 86% of the reported cases in the capital (3, 4). San Juan de Lurigancho is the most populated district in this area, with 1,004,339 inhabitants (5), and reports a pulmonary TB incidence rate of 193 cases per 100,000 inhabitants, a smear-positive TB incidence rate of 126 cases per 100,000 inhabitants (6), and an overall MDR prevalence of 7% (7), exceeding the national averages for the three indicators of 103 cases per 100,000 inhabitants, 62 cases per 100,000 inhabitants, and 5.3%, respectively (8). The HIV prevalence among TB patients in this setting is similar to the national prevalence, which in 2008 was 2.6% (9).Peru has been considered a good example of the beneficial effects of implementing directly observed therapy short course (DOTS) in a country's health system (10). Nevertheless, national surveys from 1996 and 2006 have shown increases in MDR rates from 2.4% to 5.3% among new cases and from 15.7% to 23.6% among previously treated cases (11). This paradox of improved TB management and worsening resistance prevalence has been explained by increases in the notified cases, i.e., in case detection, although treatment outcomes remain poor (12). Basically, the observed increases in MDR-TB rates may result from two factors, i.e., transmission of MDR-TB and acquired resistance due to ineffective TB treatment selecting for spontaneous mutations in specific genes associated with drug resistance (13,14).Molecular strain typing (genotyping) has significantly contributed worldwide to the understanding of TB epidemiology and transmission dynamics (15,16), by confirming outbreaks (17) and identifying the clonal spread of successful strains, including MDR strains (18,19). Furthermore, molecular typing has shown that the Mycobacterium tuberculosis complex (MTBc) has a diverse population structure, being composed of seven lineages of human

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“…A limited number of studies reporting rates of M. tuberculosis transmission from a pediatric case index are available in literature (Table 1) [15-25]. Most of these involve adolescents and describe school outbreaks [15-19]. The rate of TB transmission to contacts of smear positive adolescents varies from 7 to 39% [15,16,18] whereas transmission to contacts of smear positive younger children (7-10 years old) goes from 2 to 20% [20-22].…”

Section: Differences In Transmissionmentioning

confidence: 99%

“…No data were available about transmission rates from sputum-negative children, but two recent reports from Paranjothy et al and Baghaie et al . showed an extensive transmission from two smear negative children aged 9 and 15 years, showing that transmission of M. tuberculosis from smear-negative children is possible [17,19]. However it is not clear if contacts involved in these reports have some other risk factors for TB, for example being household contacts of adults with TB [18,20].…”

Section: Differences In Transmissionmentioning

confidence: 99%

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BMC Infect Dis

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Extensive transmission of Mycobacterium tuberculosis from 9 year old child with pulmonary tuberculosis and negative sputum smear

Cited by 29 publications

References 5 publications

Molecular epidemiology and transmission dynamics of Mycobacterium tuberculosis in Northwest Ethiopia: new phylogenetic lineages found in Northwest Ethiopia

Molecular epidemiology and transmission dynamics of Mycobacterium tuberculosis in Northwest Ethiopia: new phylogenetic lineages found in Northwest Ethiopia

Predominant Mycobacterium tuberculosis Families and High Rates of Recent Transmission among New Cases Are Not Associated with Primary Multidrug Resistance in Lima, Peru

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