Molecular Genetics

The long-range interest of the laboratory is in the genetics, biochemical and evolutionary mechanisms and epidemiology of drug resistant gram-positive pathogens, specifically, Staphylococcus spp. and Streptococcus pneumoniae. The emergence and spread of drug resistant clones of these two important pathogens pose a serious public health threat worldwide. At the same time the phenomenon also presents fascinating problems of basic science, such as the evolutionary origin of resistance genes; the mechanism of gene expression and the question of what combination of determinants provides the basis for the epidemic “success” of these pathogens. Our laboratory is actively involved both in the public health related and also in the laboratory aspects of this problem. Using techniques of molecular epidemiology, our laboratory is engaged in extensive studies on the colonization of children by S. pneumoniae in day care centers in the Lisbon area and other studies involve tracking the spread of drug resistant S. aureus clones in hospitals, in the community and in veterinary settings. Many of these studies are done in collaboration with scientists from Denmark, Germany, Iceland, Hungary, Sweden, Brazil, the United Kingdom and the USA and have been supported by the European Community, Fundação Para a Ciência e Tecnologia (FCT) and Fundação Calouste Gulbenkian (FCG). Laboratory studies involve molecular characterization of the new S. pneumoniae genotypes that emerge in response to the selective pressure of vaccines; tracking the evolutionary origin of the S. aureus ß-lactam resistance gene mecA, studies on the regulation of transcription of mecA and the nature of the numerous auxiliary genes that are essential for the expression of the resistant phenotype and elucidation of the mechanism of intermediate resistance to vancomycin in S. aureus.