Prevalence of Legionella among pneumonia patients and environmental water samples in an Egyptian University Hospital

Abstract Objectives: to diagnose Legionella infection in community- acquired pneumonia (CAP) cases admitted to chest department of Zagazig University Hospital and in hospital- acquired pneumonia (HAP) patients hospitalized in the emergency and surgery ICU, to determine incidence of these disease condition and to identify risk factors. Another objective was to determine the occurrence of Legionella genus in the water of these departments. Subjects and methods: one hundred pneumonic patients; 50 patients with CAP and 50 with HAP were the subject of this laboratory-based, comparative cross sectional study. Full clinical history and lower respiratory tract specimens were collected from each patient. Water samples were taken from 25 water outlets. DNA was extracted by QIAamp DNA Mini Kit, and real time PCR amplification of 16s r-RNA gene was used for diagnosis of Legionella genus. Risk factors were analyzed by logistic regression analysis. Results: Legionella genus was identified in eight out of 50 patients of CAP (16%), and ten out of 50 patients with HAP (20%). As regards CAP, Legionella was prevalent in old- age, smoker males, with diabetes mellitus (DM) and/or chronic obstructive pulmonary disease (COPD). Gastrointestinal tract (GIT) and neurological manifestations were the main presentations. Seventy-five percent needed ICU admission. Concerning HAP, hospitalization for more than ten days and having a stroke or head trauma were significant risk factors. Ten out of the 25 water samples tested were positive for Legionella genus; seven samples were from the chest department and three were from emergency ICU. No water-contamination with Legionella was found in the surgery ICU. Discussion: diagnosis of Legionella should be considered for both CAP and HAP in our locality. Periodic surveillance for detection of that genu s with subsequent disinfection of water sources when indicated should be carried out.