Legionella pneumophila: initial detection through evaluation of Giemsa-stained smears of a bronchial aspirate

The presence of Legionella species in a bronchial aspirate was strongly suspected by the visualization on Giemsa-stained smears of slender violaceous intra- and extracellular bacilli despite the absence of fluorescence on smears stained with L. pneumophila serogroup 1 conjugate. Subsequently, cultures of the aspirate grew L. pneumophila reactive with serogroup 6 fluorescein-conjugated antibody.