Legionnaires Disease acquired from a malfunctioning automobile air conditioner

Aquatic environments such as cooling towers, evaporaiive condensers, and potable water distribution systems, have been implicated as sources of Legionella in patients with Legionnaires Disease (LD). Here we report a patient with LD in whom the Legionella source was a malfunctioning car air conditioner. WS, a 56 yr w/m, was admitted to the hospital complaining ofcough with yellow sputum, shortness of air, and fever. Vital signs were T 104 CRR36, BP 136/80, and HR126. Physical examination was significant for rhales at LLL. At admission the WBC was 10,200 with 30% bands and the chest x-ray showed a LLL & LUL infiltrates. The diagnosis of LD was based on a (+) urinary antigen, (+) PCR test on a throat swab specimen, and a (+) PCR test in a serum sample. Sputum cultures were negative. After the diagnosis of LD was established the patient was questioned regarding contact with any aquatic environment. The patient referred that 3 days before becoming ill he had traveled from Louisville to Nashville. During the 6 hours trip the air conditioner of his car was malfunctioning and condensation of water occurred, to the point that the floor of his car was wet. A sample of the water that was leaking from the car air conditioner was fluorescent antibody (+) andPCR(+) for Legionella. Culture of the water was negative. Heteroduplex PCR analysis of the Legionella 5S rRNA amplified from the patient's serum and the car air conditioner water confirmed that both products belong to the species pneumophila. This case illustrates the importance of an appropriate history in patients with LD. Its also suggest that heteroduplex analysis may help in epidemiologic investigations of cases when cultures are negative and the only available material are PCR products.