Browsing by Author "Clemente, Sofia"
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- Clonal expansion across the seas as seen through CPLP-TB database: A joint effort in cataloguing Mycobacterium tuberculosis genetic diversity in Portuguese-speaking countriesPublication . Perdigão, João; Silva, Carla; Diniz, Jaciara; Pereira, Catarina; Machado, Diana; Ramos, Jorge; Silva, Hugo; Abilleira, Fernanda; Brum, Clarice; Reis, Ana J.; Macedo, Maíra; Scaini, João L.; Silva, Ana B.; Esteves, Leonardo; Macedo, Rita; Maltez, Fernando; Clemente, Sofia; Coelho, Elizabeth; Portugal, Isabel PortugalTuberculosis (TB) remains a major health problem within the Community of Portuguese Language Speaking Countries (CPLP). Despite the marked variation in TB incidence across its member-states and continued human migratory flux between countries, a considerable gap in the knowledge on the Mycobacterium tuberculosis population structure and strain circulation between the countries still exists. To address this, we have assembled and analysed the largest CPLP M. tuberculosis molecular and drug susceptibility dataset, comprised by a total of 1447 clinical isolates, including 423 multidrug-resistant isolates, from five CPLP countries. The data herein presented reinforces Latin American and Mediterranean (LAM) strains as the hallmark of M. tuberculosis populational structure in the CPLP coupled with country-specific differential prevalence of minor clades. Moreover, using high-resolution typing by 24-loci MIRU-VNTR, six cross-border genetic clusters were detected, thus supporting recent clonal expansion across the Lusophone space. To make this data available to the scientific community and public health authorities we developed CPLP-TB (available at http://cplp-tb.ff.ulisboa.pt), an online database coupled with web-based tools for exploratory data analysis. As a public health tool, it is expected to contribute to improved knowledge on the M. tuberculosis population structure and strain circulation within the CPLP, thus supporting the risk assessment of strain-specific trends.
- Drug resistance and genetic diversity of Mycobacterium tuberculosis in Luanda, Angola: a molecular epidemiological perspectivePublication . Perdigão, João; Clemente, Sofia; Ramos, Jorge; Masakidi, Pedro; Machado, Diana; Silva, Carla; Couto, Isabel; Viveiros, Miguel; Taveira, Nuno; Portugal, Isabel"Sub-saharan Africa contributes heavily to the tuberculosis (TB) burden worldwide. According to the World Health Organization (WHO), Africa exhibits the highest TB regional incidence rate (280 cases per 100 000 habitants) and the highest Human Immunodeficiency Virus co-infection rate (34%), both of which mostly driven by sub-saharan African countries (4). Yet, to this date, Angola has no surveillance data regarding drug resistance and the latest WHO estimates point to the occurrence of 69 000 new cases in 2013 and an incidence rate of 320 cases per 100 000 habitants in the same period (4). Additionally nothing is known regarding the genetic diversity and population structure of circulating Mycobacterium tuberculosis (M. tuberculosis) strains. Its capital city, Luanda, harbours approximately 33.7% of the country’s population and is responsible for one-third of the TB cases nationwide. In the present study, we have addressed the genetic diversity and drug susceptibility profiles of circulating M. tuberculosis strains recovered from patients followed at a central Luanda hospital unit."
- Genetic diversity, transmission dynamics and drug resistance of Mycobacterium tuberculosis in AngolaPublication . Perdigão, João; Clemente, Sofia; Ramos, Jorge; Masakidi, Pedro; Machado, Diana; Silva, Carla; Couto, Isabel; Viveiros, Miguel; Taveira, Nuno; Portugal, Isabel"Tuberculosis (TB) poses a serious public health problem in Angola. No surveillance data on drug resistance is available and nothing is known regarding the genetic diversity and population structure of circulating Mycobacterium tuberculosis strains. Here, we have genotyped and evaluated drug susceptibility of 89 Mycobacterium tuberculosis clinical isolates from Luanda. Thirty-three different spoligotype profiles corresponding to 24 different Shared International Types (SIT) and 9 orphan profiles were detected. SIT 20 (LAM1) was the most prevalent (n = 16, 18.2%) followed by SIT 42 (LAM9; n = 15, 17.1%). Overall, the M. tuberculosis population structure in this sample was dominated by LAM (64.8%) and T (33.0%) strains. Twenty-four-loci MIRU-VNTR analysis revealed that a total of 13 isolates were grouped in 5 distinct clusters. Drug susceptibility data showed that 22 (24.7%) of the 89 clinical isolates were resistant to one or more antibacillary drugs of which 4 (4.5%) were multidrug resistant. In conclusion, this study demonstrates a high predominance of LAM strains circulating in the Luanda setting and the presence of recent transmission events. The rate and the emergence dynamics of drug resistant TB found in this sample are significant and highlight the need of further studies specifically focused on MDR-TB transmission."
- HIV-1 Diversity, Transmission Dynamics and Primary Drug Resistance in AngolaPublication . Bártolo, Inês; Zakovic, Susana; Martin, Francisco; Palladino, Claudia; Carvalho, Patrícia; Camacho, Ricardo; Thamm, Sven; Clemente, Sofia; Taveira, Nuno"Objectives: To assess HIV-1 diversity, transmission dynamics and prevalence of transmitted drug resistance (TDR) in Angola, five years after ART scale-up. Methods: Population sequencing of the pol gene was performed on 139 plasma samples collected in 2009 from drug-naive HIV-1 infected individuals living in Luanda. HIV-1 subtypes were determined using phylogenetic analysis. Drug resistance mutations were identified using the Calibrated Population Resistance Tool (CPR). Transmission networks were determined using phylogenetic analysis of all Angolan sequences present in the databases. Evolutionary trends were determined by comparison with a similar survey performed in 2001. Results: 47.1% of the viruses were pure subtypes (all except B), 47.1% were recombinants and 5.8% were untypable. The prevalence of subtype A decreased significantly from 2001 to 2009 (40.0% to 10.8%, P50.0019) while the prevalence of unique recombinant forms (URFs) increased.2-fold (40.0% to 83.1%, P,0.0001). The most frequent URFs comprised untypable sequences with subtypes H (U/H, n57, 10.8%), A (U/A, n56, 9.2%) and G (G/U, n54, 6.2%). Newly identified U/H recombinants formed a highly supported monophyletic cluster suggesting a local and common origin. TDR mutation K103N was found in one (0.7%) patient (1.6% in 2001). Out of the 364 sequences sampled for transmission network analysis, 130 (35.7%) were part of a transmission network. Forty eight transmission clusters were identified; the majority (56.3%) comprised sequences sampled in 2008–2010 in Luanda which is consistent with a locally fuelled epidemic. Very low genetic distance was found in 27 transmission pairs sampled in the same year, suggesting recent transmission events. Conclusions: Transmission of drug resistant strains was still negligible in Luanda in 2009, five years after the scale-up of ART. The dominance of small and recent transmission clusters and the emergence of new URFs are consistent with a rising HIV-1 epidemics mainly driven by heterosexual transmission."