Detecting legionella pneumophila with sputum culture and urinary antigen test in patients with acute pulmonary infection

Community acquired pneumonia (CAP) is a common health problem and one of the main mortality factors worldwide. Legionella pneumophila is one of the most common responsible microorganisms for CAP and may lead to severe complications if left untreated. The present study was conducted to determine the frequency of this organism in patients with CAP.

We enrolled 118 patients with CAP, COPD and asthma in Masihdaneshvari Medical center during 2004–2005. For microbiological purposes sputum culture and legionella urinary antigen measurement were achieved.

The study population included 32 females and 86 males, their age range 58-77 years. The most frequently isolated respiratory microorganism were: streptococcus pneumonia (88%), candida spp. (76.2%), streptococcus beta-hemolytic (61.8%), staphylococcus (40.6%), klebsiella spp. (27.1%), fungi (16.1%), E.coli (8.4%), pseudomonas spp. (5.1%). Dyspnea, cough, sputum production, and fever were the most common findings. Smoking was the most commonly found risk factor.

Atypical pathogens are responsible for 40% of community-acquired pneumonia and several studies have ranked legionella pneumophila among the three most common microbial cause of CAP in patients admitted to the hospitals. So this is important to notice that urinary antigen test is particularly useful, simple and rapid test for legionella positive cases, because it is often easier to obtain urine in ill patients and the results can be available within hours and also reliable to commence treatment.