1. LEGIONELLA @ Recognized in 1976 in USA among attendees of a legion (army) convention Classification: @ It has 9 genera and 36 species L. Pneumophila is the commonest Properties: @ Gram negative rod, aerobic, flagellated

3. Structure of L. pneumophila: @ Capsule @ Outer membrane @ Inner membrane @ Blebs Antigens: @ Capsule (polysaccharide antigens) @ 8 serogroups are identified. @ Each serogroup has got specific antigen

5. Pathogenicity of legionellosis: @ It possesses: # Endotoxin # Haemolysin # Cytotoxin @ Normal flora of amoebae in water @ Survives in chlorinated water @ Transmission: # By inhaling air conditioning water. @ After inhalation, it infects the lungs.

7. Legionnaires‘ Disease Symptoms: @ Fever, dry cough, dyspnoea, diarrhoea @ Pneumonia in lung disease patients @ Encephalopathy, peripheral neuropathy. # No person to person spread.

9. Laboratory diagnosis: @ Specimens: sputum, urine, bronchoscopy @ Inoculation of guinea pigs, chick embryos, and cell cultures @ Inoculation of selective Mueller Hinton agar with hemoglobin, vitamins, cysteine @ Incubate in 5% CO 2 atmosphere. @ Identification: morphology, serology.

11. Serological diagnosis: @ Rapid microagglutination test @ Immunofluorescence antibody test. @ Antigens detected in urine by ELISA @ PCR to detect specific ribosomal RNA.

13. L. Pneumophila Sensitivity: @ Erythromycin @ Rifampicin @ Pefloxacin @ Ciprofloxacin Prophylaxis: @ Cleaning of air-conditioners & coolers @ Water chlorination every six months. @ Water pipes are made of material not supporting growth of Legionella @ Amoebicides to destroy amoebae