Uploaded byDr. Kanwal Deep Singh Lyall
Legionella
This document discusses Legionella, the bacteria that causes Legionnaire's disease. It was first identified following an outbreak of pneumonia among attendees of an American Legion convention in 1976. Legionella pneumophila is the primary causative agent. The bacteria lives in water and spreads through inhalation of contaminated water droplets. It is a gram-negative bacillus that stains poorly and grows slowly in culture. Diagnosis involves detecting the bacteria or antibodies in sputum, BAL fluid, or biopsy samples through microscopy, culture, antigen detection or serology. Erythromycin is the treatment of choice with rifampin or ciprofloxacin as alternatives. Prevention focuses on heating water systems above 60°C or chlorinating to
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Legionella
- 1. Legionella Dr. Kanwal DeepSingh Lyall M.D. Microbiology
- 2. • American Legion,Philadelphia, 1976, 221 cases of pneumonia – Legionnaire’s disease • Legionella pneumophila • Water aerosols – Acs • ≈ 40 species, L. micdadei, L. bozemanii, L. dumoffii etc.
- 3. Legionella pneumophila • GNB,GNCB, 2-5 x 0.3-0.9 µm, Longer in cultures • Motile, non-capsulated, non-sporing, Non-AFB • Microscopy-stain poorly, Ag impregnation, IFS • Catalase + ve , oxidase – ve, Hydrolysis – starch, hippurate, gelatin • >14 serogroups , human infections m/c srgp 1
- 4. Culture • Strict aerobes •Fastidious – iron & cysteine • BCYE – bufferd charcoal yeast extract & MHA containing iron & L-cysteine • 37 ° x 3-5 days – Cut glass appearance under microscope • Prolonged incubation – colonies larger & opaque
- 5. Pathogenesis • Legionnaire’s disease •Pontaic fever (mild, non-fatal influenza-like illness) • Together k/a legionellosis
- 7. Lab diagnosis • Sputum,BAL, pleural fluid, Bx etc. • Microscopy – IF using MABs, poorly stain on G/S • Culture – BYCE @ 37° C x upto 10 days • Ag detection in urine using ELISA (upto 1 m) • Serology – ELISA to detect Abs – a titre > 360 or 4 fold rise in titre is diagnostic • Rx = ERY is DOC, RIF or CIP • Prevention = heating water >60 ° C, chlorination • No vaccine
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Editor's Notes
- #3 LEGION – a large group of soldiers, Latin – Legion = gather