Mycobacteria Flashcards
What factor seen in M. tuberculosis can lead to macrophage activation and TNF-alpha release?
Cord factor
Type of leprosy associated with Th2 predominance
Lepromatous = low cell mediated
Type of leprosy associated with high cell-mediated immunity
TH1 response = tuberculoid
Aside from mycolic acids, the high lipid content in M. tuberculosis cell wall is due to
Wax D
___ assay to check for M. tuberculosis drug resistance
Luciferase assay
What prevents phagosome-lysosomal fusion of M. tuberculosis?
exported repetitive protein (sulfatides)
What triggers cell-mediated immunity, delayed hypersensitivity reaction in M. tuberculosis
Tuberculin surface protein
In a M. tuberculosis granuloma, the central area is called
Langhan Giant Cells
surrounded by a zone of epitheloid cell
A positive PPD means that ___
- Current or active disease
- Past exposure but not necessarily active disease
- BCG vaccination
M. tb drugs that inhibit mycolic acid synthesis
Isoniazid
M. tb drug that inhibits arabinosyl transferase
Ethambutol
What interleukin mediates presentation of Mtb antigen by macrophage
IL-12
What CD4 level does Mycobacterium avium-intracellulare complex appear?
CD4 <50
M. leprae can be cultured in vitro in ____
- Mouse footpad
2. Armadillo
What are the reservoirs of M. lepae
- Humans
2. Armadillos
[Tuberculoid/Lepromatous]
few lesions little tissue destruction Few AFB in skin Present CMI Lepromin positive
Tuberculoid
[Tuberculoid/Lepromatous]
many lesions Marked tissue destruction Many AFB Can highly transmit CMI reduced Lepromin negative
Lepromatous
What are the nerves commonly affected in Hansen disease?
- Ulnar and median nerve damage - clawed hand
- Common peroneal: foot drop
- Posterior tibial - plantar insensitivity and clawed toes
______ seen in lepromatous form, tender nodules or humps on both shins
Erythema Nodusum Leprosum
Tx: Thalidomide
What is the DOC for tuberculoid leprosy
- Dapsone
2. Rifampin`
What is the DOC for lepromatous leprosy?
- Dapsone
- Rifampin
- Clofazimine
[Etiology]
broken jaw or dental extraction
PE: hard, non-tender with swelling sinus tracts draining sulfur granules
Actinomyces Israelii
Tx: Pen G and drainage
What stain is used to identify Nocardia asteroides?
Fite-faraco
[Etiology]
Aerobic, filamentous gram-positive rod with aerial hyphae
manifest as mycetomas and lung and brain abscess (orange colony)
Nocardiosis
Nocardia asteroides
Tx: TMP-SMX + drainage
What is the smallest free living organism?
Mycoplasma pneunoniae
can cause walking pneumonia
Tx: erythromycin or azithromycin
What is the culture media for M. pneumoniae
Eaton agent
Needs cholesterol and nucleic acid
What is the microscopic finding of M. pnuemoniae
- Fried egg appearance OR
2. Mulberry appearance
What causes the attachment and inhibits ciliary motion of M. pneumoniae?
TLR2 protein (P1 adhesin)
__ is the only bacteria with sterol in membrane
M. pneumoniae
T. pallidum cant be cultured in vitro since ___
lacks krebs cycle
Childhood Syphilis can present with
- Interstitial keratitis
- Hutchinson Teeth
- Eight nerve deafness
What stage of syphilis can you classify Neurosyphilis that is asymptomatic
Secondary
What are the components of neurosyphilis?
- Tabes dorsalis
- Argyll-Robertson pupil or prostitues pupil
- Dementia paralytica
Argyll-Robertson Pupul presents as
- Able to accommodate when looking at near objects
2. Does not constrict with light
[Stage in Syphilis]
Endarteritis obliterans
Tertiary
___ sign
unilateral enlargement of the sternoclavicular portion of the clavicle, leads to detachment
Higoumenakis sign
Synovitis in Congenital syphilis is termed
Clutton Jint
[Stage in Syphilis]
Condyloma lata
Secondary
[Stage in Syphilis]
aortitis
tertiary
Best screening test for syphilis
Non-treponemal (VDRL/RPR)
Test for confirmation of syphilis
Treponemal antibody test
TPEIA
What are the causes of false positive VDRL results
- Viruses - EBV, Hep
- Drugs - marijuana
- Rheumatic fever, RA
- Lupus, Leprosy
____ influenza-like symptoms few hours after receiving penicillin
Jarisch-Herxheimer reaction
What is the largest medically-important bacteria
Borrelia burgdorferi
What stain is used to for B. burgdorfori
Aniline dyes (Giemsa or Wright stain)
What are the animal reservoirs of B. burgdorfori
- White-footed mouse
2. White-tailed deer
What tick transmits B. burgdorfori?
Deer ticks
Ixodes scapularis
Ixodes pacificus
[Stage og Lyme Disease]
Erythema chronicum migrans
Stage 1
[Stage og Lyme Disease]
AV block
Stage 2
[Stage og Lyme Disease]
Onion skin, acrodermatitis chronica atrophicans
Late Stage
What are the SSx of Lyme disease
- Bells palsy
- Arthritis
- Kardiak block
- Erythema chronicum migran
What is the DOC for Lyme disease
- Doxycycline
“Sheperd’s crook’
L. interrogans
Leptospires enter the human body by penetrating thorugh ___
intac mucous membrane
The meningitis and glomerulonephritis in Leptospirosis is due to
Immune complex deposition
Best source to detect organism in early stages of letospirosis
Bood, CSF
What is the gold standard to detect leptospirosis?
LeptoMAT
What is the CXR finding in leptospirosis with pulmonary involvement?
Snow-flake lesions
Asceptic meningitis due to leptospirosis coincides with ____
appearance of Ab titers
What is the triad of Weild Syndrome?
Jaundice
Bleeding
Uremia
Chlamydia trachomatis grow in ____
Cycloheximide culture
What are your obligate intracellular bacteria
- Ricketssia
2. Chlamydia
___ form of Chlamydia that is inactive, extracelular and enters via endocytosis
Elementary body Extracellular Enactive Enters via Endocytosis
____ form of Chlamydia that is metabolically active, and intracellular
Reticulate Body
What is the most common cause of STD overall?
Chlamydia
___ inclusions associated with Trachoma/Chlamydia Trachomatis
Halberstadter-Prowazek Inclusion
Round to oval near the nuclei of cinjunctival epithelial cells in trachoma
Trachoma can lead to ____
chronic infection and keratoconjunctivitis then to blindness
Most common cause of non-gonoccocal urethritis in males
C. trachomatis
Neonatal pneumonia due to C. trachomatis can present as
- Stricking tachypnea
- Paroxysmal cough (staccato cough)
- Abscence of fever
- Eosinophilia
__ test to check for C. tranchomatis (LGV) by intradermal injection of antigen
Frei test
__ cause atypical pneumonia and associated with atherosclerosis
C. pneumoniae