Sequence-based and monoclonal antibody typing of Legionella pneumophila isolated from patients in Portugal during 1987-2008.

The monoclonal antibodies and the sequence-based typing (SBT) are two methodologies widely used to characterise Legionella pneumophila strains serogroup 1 (sg1). In this study, we analysed the clinical strains received in two Portuguese laboratories since 1987, including the strains isolated in Portugal during the four years of the surveillance scheme for Legionnaires' disease implemented in 2004. In total, 63 clinical isolates of L. pneumophila sg1 were differentiated by SBT into 19 different sequence types. Ten of them were new in the SBT database of the European Working Group for Legionella Infections (EWGLI). As a result of the combination of the two methodologies, these strains were discriminated into 25 different profiles. This study enabled, for the first time in Portugal, not only to characterise the L. pneumophila sg1 clinical isolates, but also to create a database of Portuguese profiles for use in epidemiological surveillance efforts.