What are the risk factors for developing legionnaire's disease?
-chronic lung disease
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?
What are the symptoms of Legionnaire's disease?
-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"
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?
-does not have a cell wall
What is the only infectious bacteria that does not have a cell wall?
What antibiotics are used in the treatment of "atypical" pneumonia? What bugs cause atypical pneumo?
Why don't ß-lactams work against mycoplasma?
it doesn't have a cell wall
What diseases are caused by Mycoplasma?
Who is most susceptible to mycoplasma infection?
-young adults in close quarters
What diseases are caused by Chlamydia trachomatis?
- 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?
What population in the U.S. is most frequently infected with trachoma?
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?
**carried by birds
What does Chlamydophila pneumoniae cause?
How are chlamydia STI infections treated?
-1 dose IM 3G cephalosporin
-followed by 7-day course of doxycycline
(covers both chlamydia and gonorrhea)