Problematiche diagnostiche nelle infezioni sostenute da Legionella pneumophila

The introduction of the research of Legionella antigen in urine has significantly speeded up the diagnosis of Legionella pneumophila infections but has decreased the number of respiratory samples submitted for coltural examination. In 2001 respiratory samples were submitted to our laboratory only from 7% of patients for which antigen detection in urine was requested. Such a percentage decreased to 4% in 2002 and to 2.5% in 2003. For 2 of 14 patients tested in 2002, legionellosis diagnosis could not be confirmed since urine antigen detection provided weak positive values and either respiratory samples for direct isolation of L. pneumophila or blood samples for specific serology tests were lacking.We believe that even if urine antigen detection test is a very useful quick test, it cannot be considered as the only diagnostic tool in Legionella spp. infections.