Browsing by Author "Sousa, JG"
Now showing 1 - 9 of 9
Results Per Page
Sort Options
- 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.
- 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.
- 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.
- Molecular epidemiology of HIV type 1 infection in Portugal: high prevalence of non-B subtypesPublication . Esteves, A; Parreira, R; Venenno, T; Franco, M; Piedade, J; Sousa, JG; Canas-Ferreira, WIn this study, we have investigated the diversity of current HIV-1 strains circulating in the metropolitan area of Lisbon, Portugal. A total of 217 HIV-1-positive blood samples, collected between October 1998 and December 2000, was genetically characterized in the gp120 C2V3C3 region (n = 205) or part of the gp41 N-terminal segment (n = 12) by heteroduplex mobility assay (HMA) and/or DNA sequencing. The HMA subtyping efficiency (number of samples unambiguously subtyped by HMA divided by the total number of samples subtyped) was 65.9% (143 of 217), with indeterminate migration patterns of subtype A and G strains contributing significantly to this value. On the overall, subtype B was the most prevalent (50.2%), followed by subtypes G (21.7%), A (17.5%), and F (5.5%), whereas subtypes C, D, H, and J accounted altogether for 5.1% of the infections. Non-B subtypes were responsible for 77.4 and 33.1% of the infections among African immigrants and Portuguese subjects, respectively. Angolan individuals (n = 25) were the only ones infected with all the HIV-1 subtypes documented, probably reflecting a high degree of viral genetic diversification in their country of origin. Phylogenetic analysis showed a predominance of IbNG-like viruses among subtype A sequences and two new major subclusters within subtype G (G(P) and G(P)'). The majority of the Portuguese G sequences described formed a well-defined subcluster (G(P)), supported by bootstrap values >90%, phylogenetically distant from clade G sequences in databases. gag (p24/p7) sequence analysis of these variants confirmed the maintenance of the subtype G subclusters. The multiple subclustering observed for the major clades A, B, D, and G, as well as the variety of subtypes found, indicate a high diversity of HIV-1 variants circulating in Portugal and suggest a need for continuous epidemiologic surveillance.
- 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.
- Prevalence of hepatitis E virus antibody in an non endemic population: prospective studyPublication . Alberto, S; Pires, S; Félix, J; Figueiredo, A; Silva, L; Franco, M; Sousa, JG; Deus, JR
- Spoligtyping e polimorfismo do gene pncA: um cenário em duas etapas para o diagnóstico de mycobacterium bovis em PortugalPublication . David, S; Portugal, C; Antunes, A; Calado, A; Cardoso, A; Barros, V; Sancho, L; Sousa, JGThe differential diagnosis of Mycobacterium bovis is important in the control of transmission to the human population and also for treatment since M. bovis is naturally resistant to pyrazinamide. Eleven clinical isolates from the Fernando Fonseca Hospital with Spoligotypes indicative of M. bovis, through the absence of spacers 39-43 but that also counted with the absence of spacer 38, were analyzed. For the identification of these strains, the phenotypic analysis of pyrazinamide resistance and study of the polymorphisms of the pncA and gyrB genes were carried out. The study of the pncA polymorphism revealed that the strains analyzed did not contain the M. bovis specific mutation. In relation the gyrB polymorphisms, using the GenoTypeO MTBC kit, the strains were identified as belonging to the group M. tuberculosis, M. africanum subtipo II e M. canetti. The present investigation enabled us to define new genotypes on which future bacteriological studies should be based. Amongst these the study of the pncA polymorphism was considered important due to the immediate practical implications for the clinician. Evaluating transmission and defining groups of risk is an objective for which support from the veterinary services is considered relevant.
- Spreading of HIV-1 subtype G and envB/gagG recombinant strains among injecting drug users in Lisbon, Portugal.Publication . Esteves, A; Parreira, R; Piedade, J; Venenno, T; Franco, M; Sousa, JG; Patrício, L; Brum, P; Costa, A; Canas-Ferreira, WWe have evaluated the genetic diversity of HIV-1 strains infecting injecting drug users (IDUs) in Lisbon, Portugal. Heteroduplex mobility assay and/or phylogenetic analysis revealed that env (C2V3C3 or gp41) subtype B is present in 63.7% of the 135 viral samples studied, followed by subtypes G (23.7%), A (6.7%), F (5.2%), and D (0.7%). Similar analysis of gag (p24/p7) performed on 91 of the specimens demonstrated that 49.5% of the infections were caused by subtype G viruses; other gag subtypes identified were B (39.5%), F (3.3%), A and D (1.1.% each), and the recombinant circulating form CRF02_AG (5.5%). Discordant env/gag sub-types were detected in 34.1% of the strains and may reflect the presence of dual infections and/or recombinant viruses. The presumptive B/G recombinant form was highly predominant (21 of 31). The genetic pattern of HIV-1 subtype B and G strains is suggestive of multiple introductions and recombination episodes and of a longstanding presence of both subtypes in the country. C2V3C3 amino acid sequences from IDU-derived subtype G viruses presented highly significant signatures, which distinguish the variants from this transmission group. The unusually high prevalence of subtype G sequences (34.1%), independent of the geographic origin of the infected individuals, makes this IDU HIV-1 epidemic unique.
- Staphylococcus aureus reservoirs and transmission routes in a Portuguese Neonatal Intensive Care Unit: a 30-month surveillance study.Publication . Conceição, T; Sousa, M; Miragaia, M; Paulino, E; Barroso, R; Brito, MJ; Sardinha, T; Sancho, L; Carreiro, H; Sousa, JG; Machado, MC; Lencastre, HAlthough Staphylococcus aureus is a major cause of outbreaks in neonatal intensive care units (NICUs), there are no studies on the epidemiology of S. aureus isolates responsible for infection in Portuguese NICUs. Between July 2005 and December 2007, a total of 54 methicillin susceptible S. aureus (MSSA) isolates were recovered from 16 infected infants, parents, health care workers (HCWs), and the environment in a level III NICU. Isolates were characterized by pulsed-field gel electrophoresis (PFGE), spa typing, and multilocus sequence typing. Virulence determinants were detected by multiplex polymerase chain reaction. Three major MSSA clones were endemic in the NICU, representing 70% (n=38) of the isolates: PFGE type A-ST5 (n=17); type B-ST30 (n=12); and type C-ST1 (n=9). Leukotoxins and hemolysins were present in all isolates, although none of them carried PVL. HCWs, plastic folders protecting clinical files, and mothers' nipples were identified as potential reservoirs and/or vehicles of dissemination of S. aureus. Consequently, additional infection control measures were implemented in this NICU.