Legionellosis and its diagnosis

The diagnosis of legionellosis. especially of its severe, life-threatening form, Legionnaires disease, is complicated, primarily because of non-typical symptoms of the infection. not always dominating atypical pneumonia. and often a very dramatic septic course of the disease with multiorgan failures. The diagnosis of the acute phase of the disease can cc established by the detection of Legionella ant:gen 'n todne and by PAR/real-time PCR detection of Legionella DNA in serum and lower r'espiratoni tract arid urine samples. Cultivation on specific media remains the gold standard, but this very demanding methoo is rarely usea. Serological testing redu'res paired samples and thus is relevant to the diagnosis at a later stage of infection, although it is to be noted that about 20% of patients do not produce the antibodies. Great progress has been made. in typing methods (RFLP, PFGE, or PAR based and sequence based methods) and rapid identification methods (MALDI-TOF).