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Mycobacterium tuberculosis complex (MTBC) Lineage 3 (L3) strains are abundant in world regions with the highest tuberculosis burden. To investigate the population structure and the global diversity of this major lineage, we analyzed a dataset comprising 2682 L3 strains from 38 countries over 5 continents, by employing 24-loci mycobacterial interspersed repetitive unit-variable number of tandem repeats genotyping (MIRU-VNTR) and drug susceptibility testing. We further combined whole-genome sequencing (WGS) and phylogeographic analysis for 373 strains representing the global L3 genetic diversity. Ancestral state reconstruction confirmed that the origin of L3 strains is located in Southern Asia and further revealed multiple independent introduction events into North-East and East Africa. This study provides a systematic understanding of the global diversity of L3 strains and reports phylogenetic variations that could inform clinical trials which evaluate the effectivity of new drugs/regimens or vaccine candidates.
Assuntos
Mycobacterium tuberculosis , Genótipo , Testes de Sensibilidade Microbiana , Repetições Minissatélites , Mycobacterium tuberculosis/genética , FilogeniaRESUMO
BACKGROUND: Mozambique is one of the countries with the highest burden of tuberculosis (TB) in Sub-Saharan Africa, and information on the predominant genotypes of Mycobacterium tuberculosis circulating in the country are important to better understand the epidemic. This study determined the predominant strain lineages that cause TB in Mozambique. RESULTS: A total of 445 M. tuberculosis isolates from seven different provinces of Mozambique were characterized by spoligotyping and resulting profiles were compared with the international spoligotyping database SITVIT2.The four most predominant lineages observed were: the Latin-American Mediterranean (LAM, n = 165 or 37%); the East African-Indian (EAI, n = 132 or 29.7%); an evolutionary recent but yet ill-defined T clade, (n = 52 or 11.6%); and the globally-emerging Beijing clone, (n = 31 or 7%). A high spoligotype diversity was found for the EAI, LAM and T lineages. CONCLUSIONS: The TB epidemic in Mozambique is caused by a wide diversity of spoligotypes with predominance of LAM, EAI, T and Beijing lineages.
Assuntos
Variação Genética , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/isolamento & purificação , Tuberculose Pulmonar/microbiologia , Adolescente , Adulto , Feminino , Humanos , Pessoa de Meia-Idade , Dados de Sequência Molecular , Moçambique/epidemiologia , Mycobacterium tuberculosis/classificação , Tuberculose Pulmonar/epidemiologia , Adulto JovemRESUMO
BACKGROUND: Mozambique is among the highest tuberculosis, tuberculosis-HIV and multidrug-resistant-tuberculosis burden countries. Although molecular technologies are available in-country, mycobacterial isolation through culture remains an important tool for tuberculosis diagnostics and drug susceptibility testing. OBJECTIVE: We evaluated the use of the Ogawa-Kudoh (OK) mycobacterial culture, a simple technique, to isolate Mycobacterium tuberculosis in two health units, in Maputo City, Mozambique. METHODS: From May to December 2014, 122 patient samples were collected in Chamanculo General Hospital and Polana Caniço General Hospital. The specimens were first tested in the health units using the OK method and afterwards shipped to the National Tuberculosis Reference Laboratory for mycobacterial culture using the NALC-NaOH-Citrate (NALC) decontamination method followed by inoculation in Lowenstein Jensen (LJ) solid media as the reference standard. RESULTS: Among 107 samples with valid results, 98 (91.6%) had concordant results in both methods; 9 (8.4%) had discordant results. The contamination rate was 4.1% (5/122) for the OK and 9.0% (11/122) for the NALC/LJ methods. The sensitivity of OK was 80% (95% confident interval [CI]: 51.4-94.7) and the specificity was 94% (95% CI: 85.8-97.3). The degree of agreement between both methods was moderate (Kappa: 0.68; 95% CI: 0.48-0.89). CONCLUSION: The OK method showed satisfactory sensitivity and specificity. The method also had a lower contamination rate when compared to the NALC/LJ. Similar to other studies in resource-limited settings, our findings showed that the OK method can effectively be implemented in settings with limited laboratory capacity to isolate tuberculosis bacteria by culture for further testing.
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This study evaluated a National External Quality Scheme Program for early infant diagnosis of HIV. Fourteen laboratory technicians participated and nine testing panel cycles were sent between 2011 and 2014. The response rate was 100% for the first eight panels, and the number of technicians with a test score of 100% increased during the first three panels. Based on the evaluations of the technicians, the quality of testing for early infant diagnosis of HIV improved over time in the laboratories.
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BACKGROUND: Internationally-accredited laboratories are recognised for their superior test reliability, operational performance, quality management and competence. In a bid to meet international quality standards, the Mozambique National Institute of Health enrolled the National Tuberculosis Reference Laboratory (NTRL) in a continuous quality improvement process towards ISO 15189 accreditation. Here, we describe the road map taken by the NTRL to achieve international accreditation. METHODS: The NTRL adopted the Strengthening Laboratory Management Toward Accreditation (SLMTA) programme as a strategy to implement a quality management system. After SLMTA, the Mozambique National Institute of Health committed to accelerate the NTRL's process toward accreditation. An action plan was designed to streamline the process. Quality indicators were defined to benchmark progress. Staff were trained to improve performance. Mentorship from an experienced assessor was provided. Fulfilment of accreditation standards was assessed by the Portuguese Accreditation Board. RESULTS: Of the eight laboratories participating in SLMTA, the NTRL was the best-performing laboratory, achieving a 53.6% improvement over the SLMTA baseline conducted in February 2011 to the Stepwise Laboratory Quality Improvement Process Towards Accreditation (SLIPTA) assessment in June 2013. During the accreditation assessment in September 2014, 25 minor nonconformities were identified and addressed. In March 2015, the NTRL received Portuguese Accreditation Board recognition of technical competency for fluorescence smear microscopy, and solid and liquid culture. The NTRL is the first laboratory in Mozambique to achieve ISO 15189 accreditation. CONCLUSIONS: From our experience, accreditation was made possible by institutional commitment, strong laboratory leadership, staff motivation, adequate infrastructure and a comprehensive action plan.
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The Beijing genotype is a lineage of Mycobacterium tuberculosis that is distributed worldwide and responsible for large epidemics, associated with multidrug-resistance. However, its distribution in Africa is less understood due to the lack of data. Our aim was to investigate the prevalence and possible transmission of Beijing strains in Mozambique by a multivariate analysis of genotypic, geographic and demographic data. A total of 543 M. tuberculosis isolates from Mozambique were spoligotyped. Of these, 33 were of the Beijing lineage. The genetic relationship between the Beijing isolates were studied by identification of genomic deletions within some Regions of Difference (RD), Restriction Fragment Length Polymorphism (RFLP) and Mycobacterial Interspersed Repetivie Unit - variable number tandem repeat (MIRU-VNTR). Beijing strains from South Africa, representing different sublineages were included as reference strains. The association between Beijing genotype, Human Immunodeficiency Virus (HIV) serology and baseline demographic data was investigated. HIV positive serostatus was significantly (p=0.023) more common in patients with Beijing strains than in patients with non-Beijing strains in a multivariable analysis adjusted for age, sex and province (14 (10.9%) of the 129 HIV positive patients had Beijing strains while 6/141 (4.3%) of HIV negative patients had Beijing strains). The majority of Beijing strains were found in the Southern region of Mozambique, particularly in Maputo City (17%). Only one Beijing strain was drug resistant (multi-drug resistant). By combined use of RD and spoligotyping, three genetic sublineages could be tentatively identified where a distinct group of four isolates had deletion of RD150, a signature of the "sublineage 7" recently emerging in South Africa. The same group was very similar to South African "sublineage 7" by RFLP and MIRU-VNTR, suggesting that this sublineage could have been recently introduced in Mozambique from South Africa, in association with HIV infection.