Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 24
Filtrar
1.
Front Public Health ; 9: 706651, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34368069

RESUMO

Tuberculosis (TB), an airborne infectious disease caused by Mycobacterium tuberculosis complex (MTBC), remains a global health problem. West Africa has a unique epidemiology of TB that is characterized by medium- to high-prevalence. Moreover, the geographical restriction of M. africanum to the sub-region makes West Africa have an extra burden to deal with a two-in-one pathogen. The region is also burdened with low case detection, late reporting, poor treatment adherence leading to development of drug resistance and relapse. Sporadic studies conducted within the subregion report higher burden of drug resistant TB (DRTB) than previously thought. The need for more sensitive and robust tools for routine surveillance as well as to understand the mechanisms of DRTB and transmission dynamics for the design of effective control tools, cannot be overemphasized. The advancement in molecular biology tools including traditional fingerprinting and next generation sequencing (NGS) technologies offer reliable tools for genomic epidemiology. Genomic epidemiology provides in-depth insight of the nature of pathogens, circulating strains and their spread as well as prompt detection of the emergence of new strains. It also offers the opportunity to monitor treatment and evaluate interventions. Furthermore, genomic epidemiology can be used to understand potential emergence and spread of drug resistant strains and resistance mechanisms allowing the design of simple but rapid tools. In this review, we will describe the local epidemiology of MTBC, highlight past and current investigations toward understanding their biology and spread as well as discuss the relevance of genomic epidemiology studies to TB control in West Africa.


Assuntos
Mycobacterium tuberculosis , Tuberculose Resistente a Múltiplos Medicamentos , Tuberculose , África Ocidental/epidemiologia , Genômica , Humanos , Mycobacterium tuberculosis/genética , Tuberculose/diagnóstico , Tuberculose Resistente a Múltiplos Medicamentos/tratamento farmacológico
2.
PLoS One ; 16(8): e0255433, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34437584

RESUMO

Findings from previous comparative genomics studies of the Mycobacterium tuberculosis complex (MTBC) suggest genomic variation among the genotypes may have phenotypic implications. We investigated the diversity in the phenotypic profiles of the main prevalent MTBC genotypes in West Africa. Thirty-six whole genome sequenced drug susceptible MTBC isolates belonging to lineages 4, 5 and 6 were included in this study. The isolates were phenotypically characterized for urease activity, tween hydrolysis, Thiophen-2-Carboxylic Acid Hydrazide (TCH) susceptibility, nitric oxide production, and growth rate in both liquid (7H9) and solid media (7H11 and Löwenstein-Jensen (L-J)). Lineage 4 isolates showed the highest growth rate in both liquid (p = 0.0003) and on solid (L-J) media supplemented with glycerol (p<0.001) or pyruvate (p = 0.005). L6 isolates optimally utilized pyruvate compared to glycerol (p<0.001), whereas L5 isolates grew similarly on both media (p = 0.05). Lineage 4 isolates showed the lowest average time to positivity (TTP) (p = 0.01; Average TTP: L4 = 15days, L5 = 16.7days, L6 = 29.7days) and the highest logCFU/mL (p = 0.04; average logCFU/mL L4 = 5.9, L5 = 5.0, L6 = 4.4) on 7H11 supplemented with glycerol, but there was no significant difference in growth on 7H11 supplemented with pyruvate (p = 0.23). The highest release of nitrite was recorded for L5 isolates, followed by L4 and L6 isolates. However, the reverse was observed in the urease activity for the lineages. All isolates tested were resistant to TCH except for one L6 isolate. Comparative genomic analyses revealed several mutations that might explain the diverse phenotypic profiles of these isolates. Our findings showed significant phenotypic diversity among the MTBC lineages used for this study.

3.
Int J Infect Dis ; 109: 294-303, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34273514

RESUMO

OBJECTIVE: We conducted a cross-sectional study in the five administrative regions of Northern Ghana to determine the diversity of Mycobacterium tuberculosis complex (MTBC) sub/lineages and their susceptibility to isoniazid (INH) and rifampicin (RIF). METHODS: Sputum specimens were collected and cultured from 566 pulmonary tuberculosis patients reporting to 17 health facilities from 2015 to 2019. Mycobacterial isolates obtained from solid cultures were confirmed as members of the MTBC by PCR amplification of IS6110 and rpoß and assigned lineages and sub-lineages using spoligotyping. RESULTS: Of 294 mycobacterial isolates recovered, MTBC species identified were: M. tuberculosis sensu stricto (Mtbss) 241 (82.0%), M. africanum 41 (13.9%) and M. bovis four (1.4%) with eight (2.7%) unidentified. The human-adapted lineages (L) identified (N=279) were L1 (8/279, 2.9%), L2 (15/279, 5.4%), L3 (7/279, 2.5%), L4 (208/279, 74.5%), L5 (13/279, 4.7%) and L6 (28/279, 10.0%) with three unidentified lineages. Among the 208 L4, the dominant sub-lineages in the region were the Cameroon 120/208 (57.7%) and Ghana 50/208 (24.0%). We found 4.4% (13/294) and 0.7% (2/294) of the patients infected with MTBC isolates resistant to INH only and RIF only, respectively, with 2.4% (7/294) being infected with MDR strains. Whereas L6 was associated with the elderly, we identified that the Ghana sub-lineage of L4 was associated with both INH and MDR (p<0.05), making them important TB pathogens in Northern Ghana and a growing public health concern.


Assuntos
Mycobacterium tuberculosis , Preparações Farmacêuticas , Tuberculose Resistente a Múltiplos Medicamentos , Idoso , Antituberculosos/farmacologia , Antituberculosos/uso terapêutico , Estudos Transversais , Genótipo , Gana/epidemiologia , Humanos , Testes de Sensibilidade Microbiana , Epidemiologia Molecular , Mycobacterium tuberculosis/genética , Tuberculose Resistente a Múltiplos Medicamentos/tratamento farmacológico , Tuberculose Resistente a Múltiplos Medicamentos/epidemiologia
4.
Microb Genom ; 7(7)2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34241588

RESUMO

Pathogens of the Mycobacterium tuberculosis complex (MTBC) are considered to be monomorphic, with little gene content variation between strains. Nevertheless, several genotypic and phenotypic factors separate strains of the different MTBC lineages (L), especially L5 and L6 (traditionally termed Mycobacterium africanum) strains, from each other. However, this genome variability and gene content, especially of L5 strains, has not been fully explored and may be important for pathobiology and current approaches for genomic analysis of MTBC strains, including transmission studies. By comparing the genomes of 355 L5 clinical strains (including 3 complete genomes and 352 Illumina whole-genome sequenced isolates) to each other and to H37Rv, we identified multiple genes that were differentially present or absent between H37Rv and L5 strains. Additionally, considerable gene content variability was found across L5 strains, including a split in the L5.3 sub-lineage into L5.3.1 and L5.3.2. These gene content differences had a small knock-on effect on transmission cluster estimation, with clustering rates influenced by the selected reference genome, and with potential overestimation of recent transmission when using H37Rv as the reference genome. We conclude that full capture of the gene diversity, especially high-resolution outbreak analysis, requires a variation of the single H37Rv-centric reference genome mapping approach currently used in most whole-genome sequencing data analysis pipelines. Moreover, the high within-lineage gene content variability suggests that the pan-genome of M. tuberculosis is at least several kilobases larger than previously thought, implying that a concatenated or reference-free genome assembly (de novo) approach may be needed for particular questions.

5.
PLoS One ; 16(3): e0238898, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33730036

RESUMO

CONTEXT: Available molecular epidemiological data from recent studies suggest significant genetic variation between the different lineages of Mycobacterium tuberculosis complex (MTBC) and the MTBC lineages might have adapted to different human populations. AIM: This study sought to determine the population structure of clinical MTBC isolates from the Volta Region of Ghana. METHODS: The MTBC isolates obtained from collected sputum samples were identified by PCR detecting of IS6110 and genotyped using spoligotyping. Non-tuberculous mycobacterial isolates were characterized by amplification of the heat shock protein 65 (hsp65) gene and sequencing. The drug susceptibility profiles of the MTBCs determined using GenoType MTBDRplus. RESULTS: One hundred and seventeen (117, 93.6%) out of 125 mycobacterial positive isolates were characterized as members of the MTBC of which M. tuberculosis sensu stricto (MTBss) and M. africanum (MAF) were respectively 94 (80.3%) and 23 (19.7%). In all, 39 distinct spoligotype patterns were obtained; 26 for MTBss and 13 for MAF lineages. Spoligotyping identified 89 (76%) Lineage 4, 16 (13.6%) Lineage 5, 7 (6.0%) Lineage 6, 3 (2.6%) Lineage 2, 1(0.9%) Lineage 3 and 1 (0.9%) Lineage 1. Among the Lineage 4 isolates, 62/89 (69.7%) belonged to Cameroon sub-lineage, 13 (14.7%) Ghana, 8 (9.0%) Haarlem, 2 (2.2%) LAM, 1 (1.1%) Uganda I, 1 (1.1%) X and the remaining two (2.2%) were orphan. Significant localization of MAF was found within the Ho municipality (n = 13, 29.5%) compared to the more cosmopolitan Ketu-South/Aflao (n = 3, 8.3%) (p-value = 0.017). Eight (8) non-tuberculous mycobacteria were characterized as M. abscessus (7) and M. fortuitum (1). CONCLUSION: We confirmed the importance of M. africanum lineages as a cause of TB in the Volta region of Ghana.


Assuntos
Mycobacterium/genética , Tuberculose/epidemiologia , Adulto , Antituberculosos/farmacologia , DNA Bacteriano/genética , DNA Bacteriano/metabolismo , Feminino , Genótipo , Gana/epidemiologia , Humanos , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Mycobacterium/efeitos dos fármacos , Mycobacterium/isolamento & purificação , Mycobacterium tuberculosis/efeitos dos fármacos , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/isolamento & purificação , Micobactérias não Tuberculosas/genética , Micobactérias não Tuberculosas/isolamento & purificação , Prevalência , Escarro/microbiologia , Tuberculose/microbiologia , Tuberculose/patologia
6.
Int J Infect Dis ; 106: 13-22, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33667696

RESUMO

OBJECTIVE: To retrospectively investigate the cause of recurring tuberculosis (rcTB) among participants with pulmonary TB recruited from a prospective population-based study conducted between July 2012 and December 2015. METHODS: Mycobacterium tuberculosis complex isolates obtained from rcTB cases were characterized by standard mycobacterial genotyping tools, whole-genome sequencing, and phylogenetic analysis carried out to assess strain relatedness. RESULTS: The majority (58.3%, 21/36) of study participants with rcTB episodes had TB recurrence within 12 months post treatment. TB strains with isoniazid (INH) resistance were found in 19.4% (7/36) of participants at the primary episode, of which 29% (2/7) were also rifampicin-resistant. On TB recurrence, an INH-resistant strain was found in a larger proportion of participants, 27.8% (10/36), of which 40% (4/10) were MDR-TB strains. rcTB was attributed to relapse (same strain) in 75.0% (27/36) of participants and 25.0% (9/36) to re-infection. CONCLUSION: Our findings indicate that previous unresolved infectiondue to inadequate treatment, may be the major cause of rcTB.


Assuntos
Genômica , Habitação , Mycobacterium tuberculosis/genética , Tuberculose/epidemiologia , Tuberculose/transmissão , Adulto , Antituberculosos/uso terapêutico , Feminino , Gana/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Mutação , Mycobacterium tuberculosis/fisiologia , Filogenia , Recidiva , Estudos Retrospectivos , Tuberculose/tratamento farmacológico , Sequenciamento Completo do Genoma
7.
Microb Genom ; 7(2)2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33555243

RESUMO

Human tuberculosis (TB) is caused by members of the Mycobacterium tuberculosis complex (MTBC). The MTBC comprises several human-adapted lineages known as M. tuberculosis sensu stricto, as well as two lineages (L5 and L6) traditionally referred to as Mycobacterium africanum. Strains of L5 and L6 are largely limited to West Africa for reasons unknown, and little is known of their genomic diversity, phylogeography and evolution. Here, we analysed the genomes of 350 L5 and 320 L6 strains, isolated from patients from 21 African countries, plus 5 related genomes that had not been classified into any of the known MTBC lineages. Our population genomic and phylogeographical analyses showed that the unclassified genomes belonged to a new group that we propose to name MTBC lineage 9 (L9). While the most likely ancestral distribution of L9 was predicted to be East Africa, the most likely ancestral distribution for both L5 and L6 was the Eastern part of West Africa. Moreover, we found important differences between L5 and L6 strains with respect to their phylogeographical substructure and genetic diversity. Finally, we could not confirm the previous association of drug-resistance markers with lineage and sublineages. Instead, our results indicate that the association of drug resistance with lineage is most likely driven by sample bias or geography. In conclusion, our study sheds new light onto the genomic diversity and evolutionary history of M. africanum, and highlights the need to consider the particularities of each MTBC lineage for understanding the ecology and epidemiology of TB in Africa and globally.


Assuntos
Farmacorresistência Bacteriana , Mycobacterium tuberculosis/classificação , Tuberculose/microbiologia , Sequenciamento Completo do Genoma/métodos , África Oriental , África Ocidental , Evolução Molecular , Genoma Bacteriano , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/isolamento & purificação , Filogenia , Filogeografia
8.
PLoS One ; 15(7): e0236016, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32649692

RESUMO

Cholera remains a major global public health threat and continuous emergence of new Vibrio cholerae strains is of major concern. We conducted a molecular epidemiological study to detect virulence markers and antimicrobial resistance patterns of V. cholerae isolates obtained from the 2012-2015 cholera outbreaks in Ghana. Archived clinical isolates obtained from the 2012, 2014 and 2015 cholera outbreaks in Ghana were revived by culture and subjected to microscopy, biochemical identification, serotyping, antibiotic susceptibility testing, molecular detection of distinct virulence factors and Multi-Locus Variable-Number of Tandem-Repeat Analysis (MLVA). Of 277 isolates analysed, 168 (60.6%) were confirmed to be V. cholerae and 109 (39.4%) isolates constituted other bacteria (Escherichia coli, Aeromonas sobria, Pseudomonas aeruginosa, Enterobacter cloacae and Enterococci faecalis). Serotyping the V. cholerae isolates identified 151 (89.9%) as Ogawa, 3 (1.8%) as Inaba and 14 (8.3%) as non-O1/O139 serogroup. The O1 serogroup isolates (154/168, 91.7%) carried the cholera toxin ctxB gene as detected by PCR. Additional virulence genes detected include zot, tcpA, ace, rtxC, toxR, rtxA, tcpP, hlyA and tagA. The most common and rare virulence factors detected among the isolates were rtxC (165 isolates) and tcpP (50 isolates) respectively. All isolates from 2014 and 2015 were multidrug resistant against the selected antibiotics. MLVA differentiated the isolates into 2 large unique clones A and B, with each predominating in a particular year. Spatial analysis showed clustering of most isolates at Ablekuma sub-district. Identification of several virulence genes among the two different genotypes of V. cholerae isolates and resistance to first- and second-line antibiotics, calls for scaleup of preventive strategies to reduce transmission, and strengthening of public health laboratories for rapid antimicrobial susceptibility testing to guide accurate treatment. Our findings support the current WHO licensed cholera vaccines which include both O1 Inaba and Ogawa serotypes.


Assuntos
Cólera/epidemiologia , Vibrio cholerae/metabolismo , Antibacterianos/farmacologia , Cólera/diagnóstico , Cólera/microbiologia , Toxina da Cólera/genética , Toxina da Cólera/metabolismo , Surtos de Doenças , Farmacorresistência Bacteriana Múltipla/genética , Gana/epidemiologia , Humanos , Testes de Sensibilidade Microbiana , Filogenia , Sorogrupo , Sequências de Repetição em Tandem/genética , Vibrio cholerae/classificação , Vibrio cholerae/isolamento & purificação , Vibrio cholerae/patogenicidade , Virulência/genética
9.
Front Med (Lausanne) ; 7: 161, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32509791

RESUMO

Whole genome sequencing (WGS) is progressively being used to investigate the transmission dynamics of Mycobacterium tuberculosis complex (MTBC). We used WGS analysis to resolve traditional genotype clusters and explored the spatial distribution of confirmed recent transmission clusters. Bacterial genomes from a total of 452 MTBC isolates belonging to large traditional clusters from a population-based study spanning July 2012 and December 2015 were obtained through short read next-generation sequencing using the illumina HiSeq2500 platform. We performed clustering and spatial analysis using specified R packages and ArcGIS. Of the 452 traditional genotype clustered genomes, 314 (69.5%) were confirmed clusters with a median cluster size of 7.5 genomes and an interquartile range of 4-12. Recent tuberculosis (TB) transmission was estimated as 24.7%. We confirmed the wide spread of a Cameroon sub-lineage clone with a cluster size of 78 genomes predominantly from the Ablekuma sub-district of Accra metropolis. More importantly, we identified a recent transmission cluster associated with isoniazid resistance belonging to the Ghana sub-lineage of lineage 4. WGS was useful in detecting unsuspected outbreaks; hence, we recommend its use not only as a research tool but as a surveillance tool to aid in providing the necessary guided steps to track, monitor, and control TB.

10.
PLoS One ; 14(3): e0209395, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30830912

RESUMO

BACKGROUND: Bovine tuberculosis (bTB) caused by Mycobacterium bovis is a re-emerging problem in both livestock and humans. The association of some M. bovis strains with hyper-virulence, MDR-TB and disseminated disease makes it imperative to understand the biology of the pathogen. METHODS: Mycobacterium bovis (15) among 1755 M. tuberculosis complex (MTBC) isolated between 2012 and 2014 were characterized and analyzed for associated patient demography and other risk factors. Five of the M. bovis isolates were whole-genome sequenced and comparatively analyzed against a global collection of published M. bovis genomes. RESULTS: Mycobacterium bovis was isolated from 3/560(0.5%) females and 12/1195(1.0%) males with pulmonary TB. The average age of M. bovis infected cases was 46.8 years (7-72years). TB patients from the Northern region of Ghana (1.9%;4/212) had a higher rate of infection with M. bovis (OR = 2.7,p = 0.0968) compared to those from the Greater Accra region (0.7%;11/1543). Among TB patients with available HIV status, the odds of isolating M. bovis from HIV patients (2/119) was 3.3 higher relative to non-HIV patients (4/774). Direct contact with livestock or their unpasteurized products was significantly associated with bTB (p<0.0001, OR = 124.4,95% CI = 30.1-508.3). Two (13.3%) of the M. bovis isolates were INH resistant due to the S315T mutation in katG whereas one (6.7%) was RIF resistant with Q432P and I1491S mutations in rpoB. M. bovis from Ghana resolved as mono-phyletic branch among mostly M. bovis from Africa irrespective of the host and were closest to the root of the global M. bovis phylogeny. M. bovis-specific amino acid mutations were detected among MTBC core genes such as mce1A, mmpL1, pks6, phoT, pstB, glgP and Rv2955c. Additional mutations P6T in chaA, G187E in mgtC, T35A in Rv1979c, S387A in narK1, L400F in fas and A563T in eccA1 were restricted to the 5 clinical M. bovis from Ghana. CONCLUSION: Our data indicate potential zoonotic transmission of bTB in Ghana and hence calls for intensified public education on bTB, especially among risk groups.


Assuntos
Infecções por HIV/epidemiologia , Mycobacterium bovis/genética , Tuberculose Pulmonar/epidemiologia , Tuberculose Pulmonar/microbiologia , Sequenciamento Completo do Genoma/métodos , Adolescente , Adulto , Idoso , Animais , Bovinos , Criança , Comorbidade , DNA Bacteriano/genética , Farmacorresistência Bacteriana , Feminino , Gana , Humanos , Masculino , Pessoa de Meia-Idade , Epidemiologia Molecular , Mutação , Mycobacterium bovis/classificação , Mycobacterium bovis/isolamento & purificação , Filogenia , Tuberculose Bovina/epidemiologia , Tuberculose Bovina/transmissão , Adulto Jovem
11.
PLoS One ; 14(2): e0211822, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30730937

RESUMO

BACKGROUND: Diabetes Mellitus (DM) is a known risk factor for tuberculosis (TB) but little is known on TB-Diabetes Mellitus (TBDM) co-morbidity in Sub-Saharan Africa. METHODS: Consecutive TB cases registered at a tertiary facility in Ghana were recruited from September 2012 to April 2016 and screened for DM using random blood glucose and glycated hemoglobin (HbA1c) level. TB patients were tested for other clinical parameters including HIV co-infection and TB lesion location. Mycobacterial isolates obtained from collected sputum samples were characterized by standard methods. Associations between TBDM patients' epidemiological as well as microbiological variables were assessed. RESULTS: The prevalence of DM at time of diagnosis among 2990 enrolled TB cases was 9.4% (282/2990). TBDM cases were significantly associated with weight loss, poor appetite, night sweat and fatigue (p<0.001) and were more likely (p<0.001) to have lower lung cavitation 85.8% (242/282) compared to TB Non-Diabetic (TBNDM) patients 3.3% (90/2708). We observed 22.3% (63/282) treatment failures among TBDM patients compared to 3.8% (102/2708) among TBNDM patients (p<0.001). We found no significant difference in the TBDM burden attributed by M. tuberculosis sensu stricto (Mtbss) and Mycobacterium africanum (Maf) and (Mtbss; 176/1836, 9.6% and Maf; 53/468, 11.3%, p = 0.2612). We found that diabetic individuals were suggestively likely to present with TB caused by M. africanum Lineage 6 as opposed to Mtbss (odds ratio (OR) = 1.52; 95% confidence interval (CI): 0.92-2.42, p = 0.072). CONCLUSION: Our findings confirms the importance of screening for diabetes during TB diagnosis and highlights the association between genetic diversity and diabetes. in Ghana.


Assuntos
Coinfecção , Complicações do Diabetes , Infecções por HIV , HIV-1 , Mycobacterium tuberculosis , Tuberculose , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Coinfecção/diagnóstico , Coinfecção/epidemiologia , Coinfecção/microbiologia , Coinfecção/virologia , Complicações do Diabetes/diagnóstico , Complicações do Diabetes/epidemiologia , Complicações do Diabetes/microbiologia , Complicações do Diabetes/virologia , Feminino , Gana/epidemiologia , Infecções por HIV/diagnóstico , Infecções por HIV/epidemiologia , Infecções por HIV/microbiologia , Infecções por HIV/virologia , Humanos , Masculino , Pessoa de Meia-Idade , Tuberculose/diagnóstico , Tuberculose/epidemiologia , Tuberculose/microbiologia , Tuberculose/virologia
12.
J Med Microbiol ; 67(12): 1718-1727, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30388066

RESUMO

PURPOSE: Differentiation of the Mycobacterium tuberculosis complex (MTBc) from non-tuberculous mycobacteria (NTM) is important for tuberculosis diagnosis and is a prerequisite for reliable phenotypic drug-resistance testing. We evaluated the performance of the rapid MPT64 antigen identification test for the detection of Mycobacterium africanum lineage 5 (MAF L5). METHODOLOGY: Smear-positive tuberculosis patients' sputa were included prospectively. Culture was performed on Löwenstein-Jensen medium and, when positive, the MPT64 test and the classical para-nitro benzoic acid susceptibility and heat-labile catalase (PNB/catalase) identification tests were performed. The MPT64 test was repeated 14 days after an initially negative first testing. Direct spoligotyping was performed for MTBc lineage determination. RESULTS: In total, 333 isolates were tested for all of the methods. Three hundred and twenty-two (96.7 %) were pure MTBc, by agreement between spoligotyping and PNB/catalase, and 11 were NTM or a mixture of MTBc/NTM. The MPT64 test conducted on day zero of culture-positivity correctly identified most of the pure MTBc isolates (93.2 %, 300/322), but it failed to detect 24 % of the L5 isolates (18/75) versus 2 % (4/202) of the L4 ones [OR=15.6 (5.3-45.8), P<0.0001], with improved sensitivity for L5 detection on repeat testing after 14 days. The L5-wide non-synonymous single-nucleotide polymorphism in the mpt64 gene may explain the poor performance of the MPT64 test for L5. CONCLUSION: The MPT64 test has a lower sensitivity for detecting L5 isolates of the MTBc, and can be considered as a first-screening test that should be confirmed by another identification method when it produces negative results in countries with L5. Given the microbiological bias in both the isolation and identification of MAF lineages, diagnostics with high sensitivity for direct testing on clinical material are preferable.


Assuntos
Antígenos de Bactérias/isolamento & purificação , Técnicas de Tipagem Bacteriana/métodos , Mycobacterium tuberculosis/classificação , Mycobacterium tuberculosis/isolamento & purificação , Tuberculose/diagnóstico , Regulação Bacteriana da Expressão Gênica , Humanos , Polimorfismo de Nucleotídeo Único , Sensibilidade e Especificidade , Tuberculose/microbiologia
13.
Sci Rep ; 8(1): 11269, 2018 07 26.
Artigo em Inglês | MEDLINE | ID: mdl-30050166

RESUMO

Mycobacterium africanum (Maf) causes a substantial proportion of human tuberculosis in some countries of West Africa, but little is known on this pathogen. We compared the genomes of 253 Maf clinical isolates from Ghana, including N = 175 Lineage 5 (L5) and N = 78 Lineage 6 (L6). We found that the genomic diversity of L6 was higher than in L5 despite the smaller sample size. Regulatory proteins appeared to evolve neutrally in L5 but under purifying selection in L6. Even though over 90% of the human T cell epitopes were conserved in both lineages, L6 showed a higher ratio of non-synonymous to synonymous single nucleotide variation in these epitopes overall compared to L5. Of the 10% human T cell epitopes that were variable, most carried mutations that were lineage-specific. Our findings indicate that Maf L5 and L6 differ in some of their population genomic characteristics, possibly reflecting different selection pressures linked to distinct ecological niches.


Assuntos
Variação Genética , Genoma Bacteriano , Genômica , Genótipo , Mycobacterium/genética , Tuberculose/microbiologia , Gana , Humanos , Mycobacterium/classificação , Mycobacterium/isolamento & purificação
14.
Int J Infect Dis ; 73: 30-42, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29879521

RESUMO

OBJECTIVE: Understanding transmission dynamics is useful for tuberculosis (TB) control. A population-based molecular epidemiological study was conducted to determine TB transmission in Ghana. METHODS: Mycobacterium tuberculosis complex (MTBC) isolates obtained from prospectively sampled pulmonary TB patients between July 2012 and December 2015 were characterized using spoligotyping and standard 15-locus mycobacterial interspersed repetitive unit variable number tandem repeat (MIRU-VNTR) typing for transmission studies. RESULTS: Out of 2309 MTBC isolates, 1082 (46.9%) unique cases were identified, with 1227 (53.1%) isolates belonging to one of 276 clusters. The recent TB transmission rate was estimated to be 41.2%. Whereas TB strains of lineage 4 belonging to M. tuberculosis showed a high recent transmission rate (44.9%), reduced recent transmission rates were found for lineages of Mycobacterium africanum (lineage 5, 31.8%; lineage 6, 24.7%). CONCLUSIONS: The study findings indicate high recent TB transmission, suggesting the occurrence of unsuspected outbreaks in Ghana. The observed reduced transmission rate of M. africanum suggests other factor(s) (host/environmental) may be responsible for its continuous presence in West Africa.


Assuntos
Mycobacterium tuberculosis/isolamento & purificação , Tuberculose/transmissão , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Feminino , Gana/epidemiologia , Humanos , Pessoa de Meia-Idade , Repetições Minissatélites , Epidemiologia Molecular , Mycobacterium tuberculosis/genética , Estudos Prospectivos , Tuberculose/microbiologia , Adulto Jovem
15.
Am J Trop Med Hyg ; 96(5): 1076-1083, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28500810

RESUMO

AbstractThe exact route of transmission of Mycobacterium ulcerans (MU) (causative agent of Buruli ulcer [BU]), risk factors, and reservoir hosts are not clearly known, although it has been identified as an environmental pathogen. This study assessed potential environmental and behavioral risk factors that influence BU infections. We conducted a case-control study where cases were matched by their demographic characteristics and place of residence. A structured questionnaire was administered to solicit information on the environmental and behavioral factors of participants that may expose them to infection. A total of 176 cases and 176 controls were enrolled into the study. Multivariate conditional logistic regression analysis identified farming in swampy areas (odds ratio [OR] = 4.10, 95% confidence interval [CI] = 3.82-7.18), farming while wearing short clothing (OR = 1,734.1, 95% CI = 68.1-44,120.9), insect bite (OR = 988.3, 95% CI = 31.4-31,115.6), and application of leaves on wounds (OR = 6.23, 95% CI = 4.74-18.11) as potential risk factors. Farming in long clothing (OR = 0.000, 95% CI = 0.00-0.14), washing wound with water and soap (OR = 0.37, 95% CI = 0.29-0.98), and application of adhesive bandage on wounds (OR = 0.31, 95% CI = 0.15-0.82) were found to be protective against BU infection. In the absence of the exact MU transmission mechanisms, education of public in BU-endemic zones on the use of protective clothing during farming activities to limit exposure of the skin and proper wound care management would be essential in the fight against BU.


Assuntos
Úlcera de Buruli/diagnóstico , Úlcera de Buruli/prevenção & controle , Mordeduras e Picadas de Insetos/prevenção & controle , Mycobacterium ulcerans/isolamento & purificação , Roupa de Proteção , Adolescente , Adulto , Agricultura , Úlcera de Buruli/microbiologia , Úlcera de Buruli/transmissão , Estudos de Casos e Controles , Criança , Feminino , Gana , Humanos , Mordeduras e Picadas de Insetos/microbiologia , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Razão de Chances , Fatores de Risco , Rios , Inquéritos e Questionários , Áreas Alagadas
16.
Int J Mycobacteriol ; 6(1): 70-75, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28317808

RESUMO

OBJECTIVE/BACKGROUND: Nontuberculous mycobacterial (NTM) species are assuming public health importance in pulmonary diseases; they are increasingly being isolated, and importantly, most NTMs do not respond to routine tuberculosis (TB) drugs. This study aimed to identify NTMs isolated from pulmonary TB cases and also determine their susceptibility to streptomycin (STR), isoniazid (INH), and rifampicin (RIF). METHODS: A total of 1755 mycobacterial isolates, obtained between August 2012 and July 2014, from 2036 smear-positive pulmonary cases were identified using polymerase chain reaction amplification of IS6110, and hsp65 gene sequencing analysis. Drug susceptibility testing (DST) was then performed for the identified NTMs against STR, INH, and RIF using microplate Alamar blue assay. The results were analyzed against patients' biodata for statistical associations. RESULTS: Of the 1755 analyzed isolates, we identified 43 (2.5%) NTMs, which included 18 (41.9%) Mycobacterium intracellulare, 13 (30.2%) Mycobacterium avium subs. paratuberculosis, 5 (11.3%) Mycobacterium abscessus, 3 (7.0%) each of Mycobacterium mucogenicum and Mycobacterium colombiense, and 1 (2.3%) Mycobacterium simiae. Patients infected with NTMs (52.0%) were more likely to be human immunodeficiency virus-positive (P = 0.001, odds ratio = 6.6, 95% confidence interval = 2.7-16.2) than those infected with M. tuberculosis complex (5.8%). All the 43 (100%) NTMs were resistant to INH, whereas 32 (74%) and 19 (44%) were resistant to RIF and STR, respectively. Furthermore, 16 (37.2%) NTMs were resistant to all three drugs, 20 were resistant to INH and RIF, and 3 were resistant to STR and INH. All the M. abscessus isolates were resistant to all the three drugs, whereas all the M. avium isolates were resistant to INH and RIF, but only three were resistant to STR. Among the M. intracellulare isolates, 8, 18, and 15 isolates were resistant to STR, INH, and RIF, respectively. CONCLUSION: The observed high-resistance level to INH and RIF supports the need for rapid species identification and DST of nonresponding TB cases before retreatment.


Assuntos
Antituberculosos/farmacologia , Micobactérias não Tuberculosas/efeitos dos fármacos , Micobactérias não Tuberculosas/isolamento & purificação , Tuberculose Pulmonar/epidemiologia , Tuberculose Pulmonar/microbiologia , Adolescente , Adulto , Idoso , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Criança , Feminino , Gana/epidemiologia , Humanos , Isoniazida/farmacologia , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Mycobacterium tuberculosis/efeitos dos fármacos , Mycobacterium tuberculosis/genética , Micobactérias não Tuberculosas/genética , Reação em Cadeia da Polimerase , Rifampina/farmacologia , Escarro/microbiologia , Estreptomicina/farmacologia , Tuberculose Resistente a Múltiplos Medicamentos/microbiologia , Adulto Jovem
17.
Microb Ecol ; 74(2): 350-361, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28238016

RESUMO

This study aimed to contribute to the understanding of Mycobacterium ulcerans (MU) ecology by analysing both clinical and environmental samples collected from ten communities along two major river basins (Offin and Densu) associated with Buruli ulcer (BU) at different seasons. We collected clinical samples from presumptive BU cases and environmental samples from ten communities. Following DNA extraction, clinical samples were confirmed by IS2404 PCR and environmental samples were confirmed by targeting MU-specific genes, IS2404, IS2606 and the ketoreductase (KR) using real-time PCR. Environmental samples were first analysed for IS2404; after which, IS2404-positive samples were multiplexed for the IS2606 and KR gene. Our findings indicate an overall decline in BU incidence along both river basins, although incidence at Densu outweighs that of Offin. Overall, 1600 environmental samples were screened along Densu (434, 27 %) and Offin (1166, 73 %) and MU was detected in 139 (9 %) of the combined samples. The positivity of MU along the Densu River basin was 89/434 (20.5 %), whilst that of the Offin River basin was 50/1166 (4.3 %). The DNA was detected mainly in snails (5/6, 83 %), moss (8/40, 20 %), soil (55/586, 9 %) and vegetation (55/675, 8 %). The proportion of MU positive samples recorded was higher during the months with higher rainfall levels (126/1175, 11 %) than during the dry season months (13/425, 3 %). This study indicates for the first time that there is a seasonal pattern in the presence of MU in the environment, which may be related to recent rainfall or water in the soil.


Assuntos
Úlcera de Buruli/microbiologia , Mycobacterium ulcerans/isolamento & purificação , Estações do Ano , Animais , Briófitas/microbiologia , Gana , Humanos , Chuva , Reação em Cadeia da Polimerase em Tempo Real , Caramujos/microbiologia , Microbiologia do Solo , Água
18.
Int J Infect Dis ; 56: 126-129, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27979782

RESUMO

Mycobacterium africanum comprises two phylogenetic lineages within the Mycobacterium tuberculosis complex (MTBC). M. africanum was first described and isolated in 1968 from the sputum of a Senegalese patient with pulmonary tuberculosis (TB) and it has been identified increasingly as an important cause of human TB, particularly prevalent in West Africa. The restricted geographical distribution of M. africanum, in contrast to the widespread global distribution of other species of MTBC, requires explanation. Available data indicate that M. africanum may also have important differences in transmission, pathogenesis, and host-pathogen interactions, which could affect the evaluation of new TB intervention tools (diagnostics and vaccines)-those currently in use and those under development. The unequal geographical distribution and spread of MTBC species means that individual research findings from one country or region cannot be generalized across the continent. Thus, generalizing data from previous and ongoing research studies on MTBC may be inaccurate and inappropriate. A major rethink is required regarding the design and structure of future clinical trials of new interventions. The West, Central, East, and Southern African EDCTP Networks of Excellence provide opportunities to take forward these pan-Africa studies. More investments into molecular, epidemiological, clinical, diagnostic, and immunological studies across the African continent are required to enable further understanding of host-M. africanum interactions, leading to the development of more specific diagnostics, biomarkers, host-directed therapies, and vaccines for TB.


Assuntos
Interações Hospedeiro-Patógeno/imunologia , Mycobacterium/imunologia , Mycobacterium/patogenicidade , Vacinas contra a Tuberculose/imunologia , Tuberculose , África Ocidental/epidemiologia , Genótipo , Humanos , Tipagem Molecular , Mycobacterium/classificação , Mycobacterium/genética , Filogenia , Prevalência , Escarro/microbiologia , Tuberculose/diagnóstico , Tuberculose/epidemiologia , Tuberculose/prevenção & controle , Tuberculose/terapia
19.
PLoS Negl Trop Dis ; 10(10): e0004950, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27776120

RESUMO

BACKGROUND: Buruli ulcer (BU) is a subcutaneous skin disease listed among the neglected tropical diseases by the World Health Organization (WHO). Early case detection and management is very important to reduce morbidity and the accompanied characteristic disfiguring nature of BU. Since diagnosis based on clinical evidence can lead to misdiagnosis, microbiological confirmation is essential to reduce abuse of drugs; since the anti-mycobacterial drugs are also used for TB treatment. The current WHO gold standard PCR method is expensive, requires infrastructure and expertise are usually not available at the peripheral centers where BU cases are managed. Thus one of the main research agendas is to develop methods that can be applied at the point of care. In this study we selected aptamers, which are emerging novel class of detection molecules, for detecting mycolactone, the first to be conducted in a BUD endemic country. METHODS: Aptamers that bind to mycolactone were isolated by the SELEX process. To measure their affinity and specificity to mycolactone, the selected aptamers were screened by means of isothermal titration calorimetry (ITC) and an enzyme-linked oligonucleotide assay (ELONA). Selected aptamers were assessed by ELONA using swab samples from forty-one suspected BU patients with IS2404 PCR and culture as standard methods. ROC analysis was used to evaluate their accuracy and cutoff-points. RESULTS: Five out of the nine selected aptamers bound significantly (p< 0.05) to mycolactone, of these, three were able to distinguish between mycolactone producing mycobacteria, M. marinum (CC240299, Israel) and other bacteria whilst two others also bounded significantly to Mycobacterium smegmatis. Their dissociation constants were in the micro-molar range. At 95% confidence interval, the ROC curve analysis among the aptamers at OD450 ranged from 0.5-0.7. Using this cut-off for the ELONA assay, the aptamers had 100% specificity and sensitivity between 0.0% and 50.0%. The most promising aptamer, Apt-3683 showed a discernible cleavage difference relative to the non-specific autocatalysis over a 3-minute time course. CONCLUSION: This preliminary proof-of-concept indicates that diagnosis of BUD with RNA aptamers is feasible and can be used as point of care upon incorporation into a diagnostic platform.


Assuntos
Aptâmeros de Nucleotídeos/metabolismo , Úlcera de Buruli/diagnóstico , Ensaios Enzimáticos/métodos , Macrolídeos/metabolismo , Mycobacterium ulcerans/isolamento & purificação , Aptâmeros de Nucleotídeos/genética , Úlcera de Buruli/epidemiologia , Úlcera de Buruli/microbiologia , Humanos , Israel/epidemiologia , Mycobacterium smegmatis/metabolismo , Mycobacterium ulcerans/química , Mycobacterium ulcerans/metabolismo , Sistemas Automatizados de Assistência Junto ao Leito , Reação em Cadeia da Polimerase , Curva ROC , Sensibilidade e Especificidade
20.
BMC Infect Dis ; 16: 385, 2016 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-27506391

RESUMO

BACKGROUND: Mycobacterium africanum comprises two phylogenetic lineages within the M. tuberculosis complex (MTBC) and is an important cause of human tuberculosis (TB) in West Africa. The reasons for this geographic restriction of M. africanum remain unclear. Here, we performed a prospective study to explore associations between the characteristics of TB patients and the MTBC lineages circulating in Ghana. METHOD: We genotyped 1,211 MTBC isolates recovered from pulmonary TB patients recruited between 2012 and 2014 using single nucleotide polymorphism typing and spoligotyping. Associations between patient and pathogen variables were assessed using univariate and multivariate logistic regression. RESULTS: Of the 1,211 MTBC isolates analysed, 71.9 % (871) belonged to Lineage 4; 12.6 % (152) to Lineage 5 (also known as M. africanum West-Africa 1), 9.2 % (112) to Lineage 6 (also known as M. africanum West-Africa 2) and 0.6 % (7) to Mycobacterium bovis. Univariate analysis revealed that Lineage 6 strains were less likely to be isoniazid resistant compared to other strains (odds ratio = 0.25, 95 % confidence interval (CI): 0.05-0.77, P < 0.01). Multivariate analysis showed that Lineage 5 was significantly more common in patients from the Ewe ethnic group (adjusted odds ratio (adjOR): 2.79; 95 % CI: 1.47-5.29, P < 0.001) and Lineage 6 more likely to be found among HIV-co-infected TB patients (adjOR = 2.2; 95 % confidence interval (CI: 1.32-3.7, P < 0.001). CONCLUSION: Our findings confirm the importance of M. africanum in Ghana and highlight the need to differentiate between Lineage 5 and Lineage 6, as these lineages differ in associated patient variables.


Assuntos
Epidemiologia Molecular/métodos , Infecções por Mycobacterium/epidemiologia , Mycobacterium/genética , Infecções Oportunistas Relacionadas com a AIDS/epidemiologia , Infecções Oportunistas Relacionadas com a AIDS/microbiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Farmacorresistência Bacteriana/efeitos dos fármacos , Farmacorresistência Bacteriana/genética , Feminino , Gana/epidemiologia , Infecções por HIV/epidemiologia , Infecções por HIV/microbiologia , Humanos , Masculino , Testes de Sensibilidade Microbiana , Mycobacterium/efeitos dos fármacos , Mycobacterium/isolamento & purificação , Mycobacterium bovis/genética , Mycobacterium tuberculosis/efeitos dos fármacos , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/isolamento & purificação , Filogenia , Polimorfismo de Nucleotídeo Único , Estudos Prospectivos , Tuberculose/epidemiologia , Tuberculose/microbiologia , Tuberculose Pulmonar/epidemiologia , Tuberculose Pulmonar/microbiologia , Adulto Jovem
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...