FASTIDIOUS GRAM NEGATIVE RODS. PART 5 Flashcards
Legionella pneumophila
What is the most frequent cause of human legionellosis?
Legionella pneumophila
What type of pneumonia does L. pneumophila commonly cause?
community-acquired and nosocomial pneumonia
What are the two distinct clinical syndromes associated with legionellosis
Legionnaires’ disease: This is a severe form of pneumonia caused by L. pneumophila.
Pontiac Fever: A milder, flu-like illness caused by the same bacterium.
Where is L. pneumophila associated with environmental water sources?
L. pneumophila is chiefly associated with environmental water sources such as air conditioners and water-cooling towers.
What has been attributed to outbreaks of pneumonia in hospitals?
Outbreaks of pneumonia in hospitals have been attributed to the presence of L. pneumophila in water taps, sinks, and showers.
What is the exact incidence of legionellosis worldwide?
The exact incidence of legionellosis worldwide is unknown.
Which bacterium causes approximately 90% of pneumonia attributed to legionellae?
L. pneumophila causes approximately 90% of pneumonia attributed to legionellae.
What is the predominant mode of transmission for L. pneumophila?
The predominant mode of transmission for L. pneumophila is aspiration.
What are the other modes of transmission for L. pneumophila?
- Oropharyngeal colonization: This can lead to infection, especially if the person drinks contaminated water.
- Aerosol exposure: Contaminated air conditioners, nebulizers, and humidifiers can release aerosols containing the bacterium.
- Direct instillation into the lung: This can occur during respiratory tract manipulations.
Who is considered the typical candidate for Legionnaires’ disease?
The typical candidate for Legionnaires’ disease is an older man who smokes and consumes substantial amounts of alcohol.
Which patient groups are predisposed to Legionella pneumonia?
Patients with acquired immunodeficiency syndrome (AIDS), cancer, or transplants (especially renal transplants), as well as patients being treated with corticosteroids, are predisposed to Legionella pneumonia.
5 clinical manifestations of legionella pneumophila
- fever
- chills
- headache
- diarrhea
- vomiting
- fluid in the lungs
- pain in the chest and abdomen
How are Legionella organisms taken up after inhalation?
After inhalation, Legionella organisms are taken up into amoeboid phagocytes by a spirally progressing form of phagocytosis.
Where do Legionella organisms thrive inside the host cell?
They thrive inside the acidic conditions of the phagolysosome, where they multiply and eventually rupture the cell.
What type of cells do Legionella organisms adapt well to living inside
Legionella organisms adapt well to living inside amoeboid white blood cells.