Estudo molecular da resistência à rifampicina do complexo Mycobacterium tuberculosis numa população da Guiné-Bissau

Tese de mestrado. Biologia (Microbiologia aplicada). Universidade de Lisboa, Faculdade de Ciências, 2010A tuberculose é uma das doenças infecciosas mais antigas que afecta a ser humano. Segundo a Organização Mundial de Saúde, um terço da população mundial encontra-se infectada com o bacilo da tuberculose. Os dados limitados sobre a resistência aos antibacilares em países em desenvolvimento ocorre, em parte, devido à carência de condições para efectuar cultura e testes de susceptibilidade aos antibióticos (TSA). Os métodos moleculares para a detecção de mutações, que conferem resistência aos antibióticos, têm sido considerados úteis nestes contextos, podendo ser realizados em colaboração com laboratórios com capacidade de efectua-los. O estudo molecular foi realizado em amostras biológicas (expectorações) de doentes com diagnóstico presuntivo de tuberculose do Hospital de Cumura, na Guiné-Bissau. Este estudo mostrou que o Método da Lixívia, utilizado no processamento das amostras, melhora a sensibilidade da microscopia e é compatível com posterior análise molecular, e que a técnica de Cromatografia Líquida de Alta Resolução por Desnaturação (DHPLC), usada no rastreio rápido de mutações pontuais na região de 81pb determinante da resistência à rifampicina do gene rpoB (codifica para a subunidade β da RNA polimerase) de complexo Mycobacterium tuberculosis, é útil na selecção de genótipos mutantes potencialmente resistentes. As mutações foram confirmadas por sequenciação, tendo os resultados revelado uma nova mutação S469L (27/94; 28,7%) e a mutação S531L (3/94; 3,2%), esta última implicada na resistência à rifampicina. Pelo teste GenoType ® MTBDRplus, foi detectada uma estirpe multirresistente. Da análise de sequências correspondentes a estirpes de referência do GenBank, verificou-se que a mutação S469L está apenas presente na estirpe Mycobacterium tuberculosis K85. Não se sabe ainda, se esta mutação está associada a um fenótipo de resistência ou se será um possível marcador desta estirpe. Futuramente seria interessante realizar TSA e estudos genotípicos em estirpes com a mutação S469L.Tuberculosis is one of the most ancient infectious diseases affecting human beings. According to the World Health Organization, one third of the world population is infected with the tuberculosis bacillus. There is limited data on antituberculosis drug resistance in developing countries. This is partly due to the lack of conditions to perform culture and drug susceptibility testing (DST). Molecular methods for the detection of drug resistance have been considered useful in these settings as these can be carried out in collaboration with laboratories having the capacity to perform these methods. Molecular analysis was carried out on specimens from patients with presumptive diagnostic of tuberculosis of the Cumura Hospital in Guinea-Bissau. This study shows that the Bleach Method, for processing specimens, improves the sensitivity of microscopy and can be used prior to molecular analysis and that Denaturing High-Performance Liquid Chromatography (DHPLC), used for the rapid screening of point mutations in the 81 pb rifampicin resistance-determining region of the rpoB gene (enconding the beta subunit of the RNA polymerase) of Mycobacterium tuberculosis complex, could be useful in selecting potentially resistant mutants. In this study, confirmation of the mutation was performed by sequencing and the results indicated a new mutation S469L (27/96; 28,7%) and mutation S531L (3/96; 3,2%), the latter known to confer rifampicin resistance. One multidrug-resistant strain was detected by Genotype ® MTBDRplus. The mutation S469L was only detected in the Mycobacterium tuberculosis K85 strain, by analysis of sequences corresponding to reference strains from GenBank. Thus, it is not known if it is associated or not to a resistant phenotype or if it is a possible marker of these strains. It would be interesting to perform further DST and genotyping studies on strains with the S469L mutation

Validity and reliability of the Intelligibility in Context Scale: European Portuguese version

The purpose of the study was to evaluate the validity, reliability, sensitivity and specificity of the European-Portuguese version of the Intelligibility in Context Scale (ICS-EP). Seventy-six children (age: M = 60.6, SD = 8.1 months), 25 having a parent or teacher concern about how they talked and 51 with no concern, were assessed with the phonetic-phonological test (TFF-ALPE) to calculate the following severity measures: percentage of phonemes correct (PPC), percentage of consonants correct (PCC), and percentage of vowels correct (PVC). Parents also filled out a questionnaire about their child's development (e.g. concern about how the child talks). The ICS was then completed by parents to estimate their children's intelligibility with different communicative partners. The results showed that item-level scores were different according to communicative partners. The mean ICS score for the whole sample was 4.5 (SD = 0.6), showing that children were "usually" to "always" intelligible. The ICS had excellent internal consistency (α = 0.96). Children with parental concern about their speech presented significantly lower mean scores (M = 3.91, SD = 0.59) than children without parental concerns (M = 4.78, SD = 0.36). There was a positive correlation between the ICS scores and PPC (r = .655), PCC (r = .654), and PVC (r = .588). A simple linear model was also obtained between the ICS mean score and the severity measures analyzed. High values were obtained for sensitivity (0.80) and specificity (0.84), using a cut-off point of 4.36. We conclude that the ICS-EP has good psychometric properties, suggesting it to be a valid tool for estimating children's intelligibility when talking with different communicative partners. Therefore, this version of the ICS can be used as a screening measure for children's speech intelligibility.publishe

A case of imported neurocysticercosis in Portugal

PMID: 25596581 WOS:000352107800017Neurocysticercosis (NCC) is the most common cause of acquired epilepsy in resource-poor countries. We report the case of a 24-year-old woman born and residing in Guinea-Bissau, who was transferred to Portugal two months after the onset of a possible meningitis (fever, headache, seizures, and coma) that did not respond to antibiotic treatment. The diagnosis of NCC was confirmed by MR imaging, which showed multiple lesions compatible with cysticercus, and by polymerase chain reaction (PCR) of the cerebrospinal fluid. After 28 days on albendazole and dexamethasone without improvement, she was started on praziquantel, which she completed in six weeks with progressive recovery.publishersversionpublishe