Page Contents
WHAT IS IT?
Legionella pneumophillia is a gram negative bacillus (rod) bacterium. It can be visualized using a silver stain.
![Gram stain of Legionella pnumophillia (source)](http://www.stepwards.com/wp-content/uploads/2016/05/070_09.jpeg)
This pathogen is primarily intracellular, so gram stain can be limited. For this reason, a silver stain can be used to visualize the bacteria under the microscope.
![Visual appearance of intracellular Legionella pneumophillia bacterium using a silver stain (source)](http://www.stepwards.com/wp-content/uploads/2016/05/Legionella_Silver_Stain.jpg)
CULTURE CHARACTERISTICS
This bacteria is grown on charcoal yeast extract agar buffered with cysteine and iron.
MOLECULAR CHARACTERISTICS
Urine antigen can be used as a means of detecting infection.
TRANSMISSION
Aerosol transmission from environmental water sources/habitats such as air conditioners or hot water tanks. NO person to person transmission.
CONDITIONS CAUSED
General: Pontiac fever (mild flu like symptoms).
Respiratory: Legionnaires’ disease (severe pneumonia), lobar pneumonia, atypical pneumonia.
Renal: Type IV RTA that is hyporeninemic hypoaldosteronism (bacteria destroys juxtaglomerular cells in nephrons of the kidney)
TREATMENT
Macrolides or fluoroquinolones
*Treatments like penicillin are ineffective because this bacteria is intracellular!
OTHER HY FACTS
This pathogen is a facultative intracellular bacteria.
Often a community acquired pneumonia in patients who have COPD and/or are immunocompromised.
This bacteria replicates inside lung macrophages.
ARCHIVE OF STANDARDIZED EXAM QUESTIONS
This archive compiles standardized exam questions that relate to this topic.
Page Updated: 05.04.2016