Chapter 18 : Serotyping of Legionella pneumophila in Epidemiological Investigations: Limitations in the Era of Genotyping

Abstract:

The end of the 1980s was the “golden age” of Legionella pneumophila serotyping. In recent years molecular genotyping methods have been increasingly applied to the classification of legionellae. This chapter describes a short typing system for L. pneumophila that might be useful in epidemiological investigations. Serotyping of L. pneumophila is mostly done by using indirect immunofluorescence tests. However, in a European multicenter study for typing of L. pneumophila, it was demonstrated that this technique produces variable results, especially for the recognition of serogroup-cross-reactive epitopes by reagents LpH and LpK. These problems can be avoided by using an enzyme-linked immunosorbent assay (ELISA) that is a more reproducible technique because of reading of positive results with respect to the blank value, whereas microscopically judging is sometimes equivocal and influenced by the laboratory staff. ELISA allows the screening of many colonies in less than six hours. In addition, the selection of only 11 reagents combined with a blank without monoclonal antibodies (MAbs) as the 12th value was done to adapt the typing scheme to the microplate array.