Other Bacteria Flashcards
What is the life cycle of Chlamydia?
1) Elementary Body - metabolically inert, infectious particle; EB inhibits phagosome-lysosome fusion
2) Reticulate body - synthesizes its own DNA, but requires ATP from host
What are the clinical features of Chlamydia infection?
1) Conjunctivitis
2) Cervicitis
3) Atypical Pneumonia (Caused by C. psittaci and C. pneumoniae)
What does Chlamydia trachomatis infect?
1) Eyes ( can cause blindness) - A-C
2) Genitals - D-K
How does Chlamydia trachomatis cause blindness?
1) Passed from hand to hand
2) Conjunctiva scars and pulls inward
3) Eyelashes rub cornea and cause scaring
Chlamydia trachomatis may also be passed to babies delivered through infected birth canal. These babies develop ________.
1) Inclusion conjunctivits
2) Treated with erythromycin drops
Carried by birds, spread by feces through air, microorganism enters UR and invades blood via alveoli
Chlamydia psittaci
What are the two responses to mycobacterium leprae?
1) tuberculoid leprosy (strong immune response) - Granuloma formation limits spread, localized damage to superficial nerves
2) lepromatous leprosy ( weak immune response) - host defense is unable to prevent spread, inflammatory damage at cooler skin, causes sensory loss
Acid fast, thin rods, non-motile, obligate aerobe, grows at low temperatures
Mycobacterium leprae
What causes cells to be acid fast?
1) Presence of mycolic acid in the cell wall
2) renders cell resistance to phagocytosis
Bacteria that cause the formation of caseous granulomas within the lungs
Myobacterium tuberculosis
Findings of a Primary TB infection
1) Ghon complex (granuloma + hilar lymph nodes)
2) Fibrotic calcified scars
Findings of a Secondary TB infection
1) Cavitations in lungs due to large granulomas
2) May disseminate (miliary TB)
How do you treat a M. tuberculosis infection?
RIPES
1) Rifampin
2) Isoniazid (INH)
3) Pyrazinamide
4) Ethambutol
5) Streptomycin
Microorganism carried in cattle that survives as a spore; causes Q fever, atypical pneumonia; does not cause rash
Coxiella burnetii
Obligate intracellular parasite that replicates freely in the cytoplasm; transmitted by louse; organism infects endothelial cells; + Weil-Felix test; causes rash on trunk and spreads outward; common in trench warfare
Rickettsia prowazekii
Cause of Brill-Zinsser Disease. What are the symptoms?
1) Rickettsia prowazekii
2) Typhus
3) Reinfection of latent organism
Maculopapular rash on palms and soles that spreds to the trunk; wide spread vasculitis causing fever and headache
1) Rocky mountain spotted fever
2) Caused by Ricketssia rickettsii
Test that uses Proteus vulgaris antigens to diagnose Rickettsia
Weil-Felix Test
What is the cause of Lyme’s disease
Borrelia burgdorferi
What are complications of infection from Borrelia burgdorferi?
think: FAKE a key lyme pie
1) Erythema (annular red rash with clear center)
2) CNS: Bell’s palsy, aseptic meningitis, peripheral neuropathy
3) CV: carditis, AV nodal block
4) Joints: migratory myalgias
Cause of relapsing fever
Borrelia recurrentis
Why does Borrelia recurrentis cause relapsing fever?
1) It is due to its antigenic variation in its outer membrane
What are the clinical stages of Treponema pallidum (syphilis)
1) Primary syphilis = painless chancre
2) Secondary syphilis = condyloma lata, maculopapular rash on palms and soles; meningitis
3) Tertiary syphilis = gummas (granulomas of the soft tissue and bone)
4) Can also cause Ascending aortic aneurysm (tree bark appearance)
What is used to diagnose Treponema pallidum
1) VDRL (veneral disease researhc lab test) (nonspecific)
2) FTA-ABS (Fluoresence Trepenoma antibody) (specific)
3) RPR (Rapid plasma reagin test) (nonspecific)
Motile spirochete with 2 periplasmic flagella with hooked ends that appear as ice tongs
Leptospira interrogans
Bacteria with no cell wall that causes walking pneumonia; fried- egg appearance on serology; beta lactam resistant
Mycoplasma pneumoniae
How does Mycoplasma pneumoniae cause atypical pneumonia?
It inhibits the motion of cilia causing inflammation
What is a finding used for diagnosis related to Mycoplasma pneumoniae?
Cold aggluttin test- B cells produce antibodies that may autoreact with erythrocytes
Treatment for Chlamydia?
Azithromycin
Treatment for Rickettsia rickettsii
1) Doxycycline (do not give to younger than 18)
2) Chloramphenicol (alternative for doxycycline)
Homeless man enters with wasting and fever. Chronic cough, bloody sputum and night sweats. Positive acid fast staining
Myobacterium tuberculosis
Treatment for Trepenoma pallidum (syphilis)?
Penicilin G
Treatment for Mycoplasma pneumoniae
1) Erythromycin (macrolide)
2) Tetracycline
What is an RPR test? What is it testing for?
1) Addition of cardiolipin, lecithin, and cholesterol to serum; positive if floculation (aggregation) occurs
2) Tests for trepenoma
What is the MOA of Rifampicin?
Inhibits bacterial DNA dependent RNA polymerase
What is the MOA of Ethambutol
Inhibits arabinosyl transferase resulting in the inhibition of carbohydrate polymerization
What is the MOA of Isoniazid
Inhibits mycolic acid synthesis
What is the MOA of streptomycin
Inhibition of 30s ribosome (aminoglyside)
Adverse effects of ethambutol
Optic neuritis
Adverse effects of isoniazid
1) Liver toxicity
2) Peripheral neuropathy
Prophylaxis against myobacterium avium complex?
Azithromycin
When is Myobacterium avium complex most commonly cause infx?
In HIV with CD4 counts less than 50
What must Myobacterium have in order to cause disease?
1) Cord factor
MOA of Pyrazinamide
1) Works best at an acidic pH
2) Works well against engulfed TB
Acid fast bacilli that grows at 41 C and when CD4 count <50
Myobacterium avium complex
What do the presence of Myobacterium growing in serpentine cords indicate?
1) Presence of Mycoside (cord factor)
2) Indicates virulence
What is the only bacteria that requires cholesterol to grow on media?
Mycoplasma
Pt. complains of chronic dry nagging cough, low grade fever, and malaise; X-ray looks much worse than the pt. appears clinically
Mycoplasma pneumoniae
