الفهرس 
AcknowledgmentOnly 14 pages are availabe for public view
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Abstract
Pneumonia is an infection of pulmonary parenchyma . Various bacterial species , Mycoplasmas , Chlamydiae, Rickettsiae, viruses , fungi and parasites can cause pneumonia . Thus pneumonia is not a single disease but a group of specific infections each with a different epidemiology , pathogenesis, clinical presentation and clinic course . In the summer of 1976 public attention focused on an outbreak of severe pneumonia that had a high mortality rate for members of the American Legion convention in Philadelphia . After months of intensive investigations the etiological agent, a previously unknown Gram-negative bacillus, was isolated . In subseqent studies this organism, named Legionella pneumophila, has been associated with at least four epidemics before 1976 and multiple epidemic and sporadic infections after 1976. The organism is ubiquitous in water and is present in the water supply or cooling towers particularly if there is active construction . Contaminated potable water is probably the most important hospital reservoir of Legionella. It is acquired by inhalation and particularly those patients who are immunosupressed or on corticosteroids . The present study aimed at the determination of the extent to which Legionella spp. share in the lower respiratory tract infection in the Main University Hospital of Alexandria . This study was carried out over a 5 months from June to November 1997, It included 144 patients with lower respiratory tract infection ( 106 males and 38 females ) admitted to the Chest Department of Main University Hospital-Alexandria. Their age ranged from 18 to 90 years . Forty six patients were clinically diagnosed as pneumonia, 69 as COPD, 21 as bronchiectasis and 8 as bronchiectasis and COPD. Pneumonia was diagnosed by radiographic demonstration of pulmonary infiltrates and symptoms compatible with pneumonia ( fever > 380C and /or symptoms of acute respiratory tract infection ). The detailed history was recorded including name, age, sex, past history of chest problems, date of onset of illness, exposure to air conditioning and antibiotic administration . Sputum specimen were collected from all 122 outpatient and inpatient groups. All 22 patients in the ICUs were sampled through tracheobronchial secretion or endotracheal aspirate . At the laboratory each specimen was divided into 2 portion : • The first was directly inoculated onto each of blood, chocolate and MacConkey’s agar plates and were incubated aerobically at 370C for 24h. • The other portion used for the isolation of legionella was pretreated with acid buffer to reduce contaminating microbes and then plated onto BCYE agar and incubated aerobically for 3-5 days at 370C. • The isolated colonies were examined for their morphological and biochemical characters . The results of the study can be summarized as follows : (1) No legionella spp. were isolated from any the collected samples .