What are the risk factors for developing legionnaire's disease?
-smoking
-chronic lung disease
-age
-transplant status
-immunosuppression
What is the disadvantage for using urinary legionella antigen test for legionella?
-specific for L. pneumophila serogroup 1
-highly specific, variable sensitivity
How is the reproductive cycle of Chlamydia unique?
-Elementary bodies = extracellular, infects cells, phagocytosed by alveolar macrophages
-Reticulate body = intracellular, replicates inside "inclusion body," revert to EB's before burst
What is Lymphogranuloma venereum (LGV)? What causes it?
-STI manifesting as inguinal lymphadenopathy
-Primary = genital ulcer at site of innoculation
-Secondary = painful inguinal lymphadenopathy & groove sign
-Caused by Chlamydia trachomatis
How are Legionella, Mycoplasma, and Chlamydia related?
-they lead to "atypical pneumonia"
How is atypical pneumonia characterized?
-indolent (slow growing) onset
-often extrapulmonary symptoms
-many times, normal WBC, but other lab abnormalities
-Difficult to diagnose, Gm staining not helpful
What is the treatment for atypical pneumonia?
-New macrolides
-respiratory fluroquinolones
What are the symptoms of Legionnaire's disease?
"atypical pneumonia"
-GI symptoms
-High fever
-Thrombocytopenia
-Hyponatremia
-Altered mental status often seen
What is Cold agglutinin disease? What causes it?
-body produces IgM that attack RBCs
-used as diagnostic test, put tube of blood on ice and blood will clump which means...
-caused by Mycoplasma infection
"pneumonia w/ hyponatremia & diarrhea"
Legionaires
What two diseases are caused by Legionella pneumophila?
1. Legionnaire's disease
2. Pontiac Fever
What is the gram stain of legionella?
-gram (-) but needs silver stain to be visualized
Describe pontiac fever. What causes it?
-headache, myalgia, fatigue, sudden onset fever and chills
-lasts for a week (self limiting)
Caused by Legionella pneumophila
What is the gram stain of mycoplasma?
-Neither
-does not have a cell wall
What is the only infectious bacteria that does not have a cell wall?
Mycoplasma
What antibiotics are used in the treatment of "atypical" pneumonia? What bugs cause atypical pneumo?
Abx:
- Macrolides
- tetracyclines
- quinolones
Bugs:
- Legionella
- Mycoplasma
- Chlamydia
Why don't ß-lactams work against mycoplasma?
it doesn't have a cell wall
What diseases are caused by Mycoplasma?
-"walking pneumonia"
Who is most susceptible to mycoplasma infection?
-young adults in close quarters
*military recruits
"guillan-barre"
-Mycoplasma
What diseases are caused by Chlamydia trachomatis?
- Trachoma
- conjunctivitis (usually newborn)
- infant pneumonia
- Lymphogranuloma venereum (LVG)
- Reiter's syndrome (reactive arthritis)
What is Reiter's syndrome? What bug causes it?
-can't see (uveitis)
-Cant pee (urethritis)
-Can't climb a tree (reactive arthritis)
Caused by Chlamydia trachomatis
What is trachoma? What bug causes it?
-leading cause of preventable blindness in the world
-conjunctival infection caused by Chlamydia trachomatis
-Scarring traction can pull eyelid inward so that eyelashes rub against conjunctiva
What is the leading preventable cause of blindness in the world?
-Trachoma
(Chlamydia trachomatis)
What population in the U.S. is most frequently infected with trachoma?
Native Americans
Why don't B-lactams work on Chlamydia species?
-they don't have peptydoglycan/muramic acid in their cell wall
What does Chlamydophyla psittaci cause?
-Atypical pneumonia
**carried by birds
What does Chlamydophila pneumoniae cause?
-atypical pneumonia
How are chlamydia STI infections treated?
-1 dose IM 3G cephalosporin
-followed by 7-day course of doxycycline
(covers both chlamydia and gonorrhea)
"groove sign"
-Lymphogranuloma venerum
-Chlamydia trachomatis
