Browsing by Author "Sancho, L"
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- Bactérias vs antimicrobianos: who's the winner?Publication . Serra, I; Almeida, P; Oliveira, MJ; Sancho, L
- Contribution of spoligotyping to the characterization of the population structure of Mycobacterium tuberculosis isolates in PortugalPublication . David, S; Ribeiro, D; Antunes, A; Portugal, C; Sancho, L; Sousa, JGTuberculosis is a major health problem in Portugal. To begin characterizing the population structure of Mycobacterium tuberculosis, spoligotyping was used for the systematic typing, through consecutive sampling, of patient isolates from the Amadora-Sintra area of Greater Lisbon. Distribution amongst major spoligotype families, including the Latin American Mediterranean (LAM), T, Haarlem and Beijing, was compared to that of the international spoligotype database SpolDB4 and to the European countries of traditional Portuguese immigration represented in SpolDB4. Spoligotypes from 665 isolates were analyzed and 97 shared international types (SITs) identified. In SpolDB4 Portugal is represented by part of the spoligotypes from this study explaining the reduced number of unidentified patterns. The importance of the LAM family, and especially of LAM1 and LAM9 sub-families that alone represented 38% of all the isolates in this study as compared to 8% relative to the European sub group, led us to believe that at least in this respect the population structure was closer to that of Africa and South America than to Europe. Spoligotypes characteristic of Portugal or Portuguese related settings were identified. These included SIT244 a T1 sub-family predominant in Portugal and Bangladesh, SIT64 a LAM 6 sub-family common to Portugal and Brazil, and SIT1106 a LAM 9 sub-family. These studies were the first in Portugal stressing the importance of monitoring the population structure of M. tuberculosis isolates, an important step towards gaining an understanding of tuberculosis and the dynamics of this disease.
- Determinants of the Sympatric Host-Pathogen Relationship in TuberculosisPublication . David, S; Mateus, AR; Duarte, EL; Albuquerque, J; Portugal, C; Sancho, L; Lavinha, J; Gonçalves G, GMajor contributions from pathogen genome analysis and host genetics have equated the possibility of Mycobacterium tuberculosis co-evolution with its human host leading to more stable sympatric host-pathogen relationships. However, the attribution to either sympatric or allopatric categories depends on the resolution or grain of genotypic characterization. We explored the influence on the sympatric host-pathogen relationship of clinical (HIV infection and multidrug-resistant tuberculosis [MDRTB]) and demographic (gender and age) factors in regards to the genotypic grain by using spacer oligonucleotide typing (spoligotyping) for classification of M. tuberculosis strains within the Euro-American lineage. We analyzed a total of 547 tuberculosis (TB) cases, from six year consecutive sampling in a setting with high TB-HIV coinfection (32.0%). Of these, 62.0% were caused by major circulating pathogen genotypes. The sympatric relationship was defined according to spoligotype in comparison to the international spoligotype database SpolDB4. While no significant association with Euro-American lineage was observed with any of the factors analyzed, increasing the resolution with spoligotyping evidenced a significant association of MDRTB with sympatric strains, regardless of the HIV status. Furthermore, distribution curves of the prevalence of sympatric and allopatric TB in relation to patients' age showed an accentuation of the relevance of the age of onset in the allopatric relationship, as reflected in the trimodal distribution. On the contrary, sympatric TB was characterized by the tendency towards a typical (standard) distribution curve. Our results suggest that within the Euro-American lineage a greater degree of genotyping fine-tuning is necessary in modeling the biological processes behind the host-pathogen interplay. Furthermore, prevalence distribution of sympatric TB to age was suggestive of host genetic determinisms driven by more common variants.
- Direct application of the INNO-LiPA Rif.TB line-probe assay for rapid identification of Mycobacterium tuberculosis complex strains and detection of rifampin resistance in 360 Mycobacterium tuberculosis complex strains and detection of rifampin resistance in 360 smear-positive respiratory specimens from an area of high incidence of multidrug-resistant tuberculosisPublication . Viveiros, M; Leandro, C; Rodrigues, L; Almeida, J; Bettencourt, R; Couto, I; Carrilho, L; Diogo, J; Fonseca, A; Lito, L; Lopes, J; Pacheco, T; Pessanha, M; Quirim, J; Sancho, L; Salfinger, M; Amaral, LThe INNO-LiPA Rif.TB assay for the identification of Mycobacterium tuberculosis complex strains and the detection of rifampin (RIF) resistance has been evaluated with 360 smear-positive respiratory specimens from an area of high incidence of multidrug-resistant tuberculosis (MDR-TB). The sensitivity when compared to conventional identification/culture methods was 82.2%, and the specificity was 66.7%; the sensitivity and specificity were 100.0% and 96.9%, respectively, for the detection of RIF resistance. This assay has the potential to provide rapid information that is essential for the effective management of MDR-TB.
- Genetic Background and Expression of the New qepA4 Gene Variant Recovered in Clinical TEM-1- and CMY-2-Producing Escherichia coli.Publication . Manageiro, V; Félix, D; Jones-Dias, D; Sampaio, D; Vieira, L; Sancho, L; Ferreira, E; Caniça, MA new QepA4 variant was detected in an O86:H28 ST156-fimH38 Escherichia coli, showing a multidrug-resistance phenotype. PAβN inhibition of qepA4-harboring transconjugant resulted in increase of nalidixic acid accumulation. The qepA4 and catA1 genes were clustered in a 26.0-kp contig matching an IncF-type plasmid, and containing a Tn21-type transposon with multiple mobile genetic elements. This QepA variant is worrisome because these determinants might facilitate the selection of higher-level resistance mutants, playing a role in the development of resistance, and/or confer higher-level resistance to fluoroquinolones in association with chromosomal mutations.
- High prevalence of ST121 in community-associated methicillin-susceptible Staphylococcus aureus lineages responsible for skin and soft tissue infections in Portuguese childrenPublication . Conceição, T; Aires-de-Sousa, M; Pona, N; Brito, MJ; Barradas, C; Coelho, R; Sardinha, T; Sancho, L; Sousa, JG; Machado, MC; Lencastre, HIn order to evaluate the incidence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) in Portugal, we analyzed a collection of 38 S. aureus isolates recovered from 30 children attending the pediatric emergency department of a central hospital in Lisbon due to skin and soft tissue infections. Molecular characterization identified seven clonal lineages among the 35 methicillin-susceptible S. aureus (MSSA) isolates, of which the major lineage PFGE A/t159/ST121 included 63% of the isolates. The three MRSA isolates belonged to the Pediatric clone PFGE D/t535/ST5-IV (n = 2) and to the European CA-MRSA clone PFGE G/t044/ST80-IVc (n = 1). All isolates harbored several virulence factors, namely, leukocidins. Panton-Valentine leukocidin (PVL) was produced by isolates from five MSSA lineages and by the ST80 MRSA. Of interest, this is the first reported isolation of CA-MRSA ST80 in Portugal.
- Identificação molecular pelo método de Spoligotyping de estirpes do complexo Mycobacterium tuberculosis isoladas no Hospital Fernando FonsecaPublication . David, S; Portugal, C; Antunes, A; Cardoso, A; Calado, A; Barros, V; Sancho, LSpoligotyping was used in the genotyping of 219 isolates of the Mycobacterium tuberculosis complex, from patients of the Hospital Fernando Fonseca. This technique, based on PCR methodology, analyses a region of the chromosome specific of the Mycobacterium tuberculosis complex, the DR locus (Direct Repeat). With the aid of an international database, we showed that the predominant Spoligotypes belonged to the LAM family (Latino-American Mediterranean), 29.2 %. The LAM 9 family, with 12.3 %, left us attentive to the possible import of the disease through populations from South America, were it has been frequently identified. The genotypic families T1 and Haarlem, with 6.4 % and 8.7 % respectively, represented a frequency typical to Europe. The Beijing family, with 1.4 %, may represent an emerging problem in our country due to recent immigration of Asian and Eastern European populations. Isolates with a Spoligotype of the M. bovis type were found at a high percentage, 3.7 %. In Europe, this infection is extremely rare suggesting the result may not be due to M. bovis infection but to M. bovis BCG (due to vaccination or eventual recombinant BCG based therapies), or M. africanum (due to the proximity of the two species). A high percentage of the Spoligotypes were not identified by the database, 21.4 %. This is the first study of this type amongst us and may be the starting point for the creation of a data base with important consequences on the national program against tuberculosis.
- Implication of the RD(Rio)Mycobacterium tuberculosis sublineage in multidrug resistant tuberculosis in PortugalPublication . David, S; Duarte, E; Leite, C; Ribeiro, J; Maio, J; Paixão, E; Portugal, C; Sancho, L; Sousa, JGMultidrug and extensively drug resistant Mycobacterium tuberculosis are a threat to tuberculosis control programs. Genotyping methods, such as spoligotyping and MIRU-VNTR typing (Mycobacterial Interspersed Repetitive Units), are useful in monitoring potentially epidemic strains and estimating strain phylogenetic lineages and/or genotypic families. M. tuberculosis Latin American Mediterranean (LAM) family is a major worldwide contributor to tuberculosis (TB). LAM specific molecular markers, Ag85C(103) single nucleotide polymorphism (SNP) and RD(Rio) long-sequence polymorphism (LSP), were used to characterize spoligotype signatures from 859 patient isolates from Portugal. LAM strains were found responsible for 57.7% of all tuberculosis cases. Strains with the RD(Rio) deletion (referred to as RD(Rio)) were estimated to represent 1/3 of all the strains and over 60% of the multidrug resistant (MDR) strains. The major spoligotype signature SIT20 belonging to the LAM1 RD(Rio) sublineage, represented close to 1/5th of all the strains, over 20% of which were MDR. Analysis of published datasets according to stipulated 12loci MIRU-VNTR RD(Rio) signatures revealed that 96.3% (129/134) of MDR and extensively drug resistant (XDR) clusters were RD(Rio). This is the first report associating the LAM RD(Rio) sublineage with MDR. These results are an important contribution to the monitoring of these strains with heightened transmission for future endeavors to arrest MDR-TB and XDR-TB.
- Novos dados sobre os Spoligotypes de estirpes do complexo Mycobacterium tuberculosis isoladas no Hospital Fernando Fonseca (Amadora-Sintra, Portugal)Publication . David, S; Barros, V; Portugal, C; Antunes, A; Cardoso, A; Calado, A; Sancho, L; Sousa, JGO presente estudo populacional, que decorreu entre 1999 e 2003, foi baseado na utilização do Spoligotyping na genotipagem de 452 isolados do complexo Mycobacterium tuberculosis de doentes com tuberculose internados no Hospital Fernando Fonseca. Spoligotypes foram identificados como shared types (ST) recorrendo a uma base de dados internacional. Onze ST raros, não identificados na base de dados, acomodaram 8,4% dos isolados. Aliás, particular a Portugal poderá ser a predominância de ST identificados na base de dados mas não previamente classificados como famílias genotípicas, tais como o ST244, ST150 e ST389, representando 13,3 % do total. A identificação de isolados clínicos de M. africanum de genótipo Afri1 e de M. tuberculosis de genótipo CAS1 poderá confirmar a importação de isolados de origem africana e asiática. M. tuberculosis da família Beijing foi pela primeira vez por nós assinalado a partir de 1999. Desde então, o número de isolados provenientes do hospital passou de um para cinco, anualmente, representando actualmente 2,2%, o que a coloca em décimo lugar em prevalência. M. tuberculosis Beijing poderá corresponder a um problema emergente em Portugal devido à recente imigração proveniente da Europa Oriental e da Ásia. Outros genótipos, ST150 e ST389, mostraram um incremento, cujo significado não é claro. No entanto, as frequências relativas das famílias predominantes LAM, T1 e Haarlem mantiveram-se relativamente estáveis. O presente estudo confirma a variabilidade genética em Portugal dos isolados do complexo M. tuberculosis. Estes estudos poderão contribuir para a definição de prioridades nos programas nacionais de luta contra a tuberculose.
- Prevalência dos utentes com tempo de tromboplastina parcial activado baixo, na população do Hospital Prof. Doutor Fernando da Fonseca, EPEPublication . Santos, MA; Aliyeva, E; Salazar, F; Silva, L; Sancho, LIntrodução: A doença tromboembolica venosa (TEV) constitui um problema de grande impacto na saúde pública pela sua morbilidade e mortalidade. Tem uma etiologia multifactorial e os factores de risco são aditivos. Segundo vários estudos publicados a determinação de um tempo de tromboplastina parcial activado (TTPa) baixo, associa-se per se a um risco au- mentado de TEV. Objectivo: Cálculo da prevalência dos valores de TTPa inferiores ao Valor de Referência, VR, (excluíram-se utentes com trombofilias hereditárias/adquiridas). Materiais e Métodos: Realizou-se um estudo analítico observacional e longitudinal, no espaço temporal de Abril a Maio de 2014. Definiram-se três populações: 1ª - Dadores de sangue, (15 homens, 15 mulheres), para cálculo do VR, (colabora- ção do Serviço de Imunohemoterapia do Hospital Prof. Doutor Fernando Fonseca, E.P.E. (HFF). 2ª - Casuística dos utentes adultos em ambulatório, com prescrição de TTPa, no espaço temporal definido, 12943. 3ª População – Utentes com uma razão de TTPa <0.95 (razão = valor utente/valor referência) excluíram-se condições hereditárias/adquiridas potencialmente interferentes na hemostase. Utilizou-se o coagulometro BCS-XP® e o reagente TTPa ACTIN FS® da rotina do Laboratório de Hematologia. Cálculos no Excel para Windows 2010 Resultados 1.Cálculo da média: 24,4s; Intervalo de Confiança (90%): 20,6 a 29,5 s 2. Estudo precisão do reagente para TTPa ACTIN FS® Média 24,38 Variância 0,03 Mediana 24,36 Nível de confiança 90,0% 0,06 Desvio-padrão 0,17 Erro-Padrão 0,04 3.Cálculo de prevalências: Casuística dos TTPa: 12943 utentes, prevalência dos TPPa baixos na população, 5,9%. Preva- lência dos TPPa com uma razão <0.95 em utentes sem alterações da hemostase adquridas/hereditárias identificadas, 1,9%. Conclusões: Obtivemos uma prevalência de 1,9% de utentes (sem alterações da hemostase adquiridas/hereditárias identi- ficadas) com TTPa abaixo da razão de 0.95, em 12943 utentes. Sabendo que os valores baixos de TTPa se correlacionam com um risco aumentado de doença tromboembolica, pensamos que, este teste simples e de baixo custo, possa vir a ser utilizado no futuro, em sinergia com outros factores de risco na sua avaliação.