weird bacteria Flashcards
rickettsia rickettsii: clinical presentation, how is it spread, diagnosis, classification, treatment
this causes rocky mountain spotted fever.
presents as a rash that begins on the wrist and ankles, then progresses to the palms and soles, and trunk. this rash is actually due to a vasculitis.
It also presents as fever and headache.
vector: tick
all rickettsia are obligate intracellular ogranizims that need CoA and NAD+ because they can’t synthesize ATP. they typically replicate within the cytoplasm. treatment for all rickettsia is doxycycline
treatment: doxycycline
may see a positive Weil-Felix test
Erlichiosis: clinical presentation, vector
tick vector
presents as monocytes with morulae in the cytoplasm
rash is rare
tx: doxycycline
anaplasmosis
rickettsial disease in which rash is rare.
vector is tick. granulocytes with morulae in the cytoplasm
tx: doxycycline
typhus: types, spread, rash
endemic: spread by fleas and caused by R. typhi
epidemic: spread by human body louse and caused by R. prowazekii.
rash starts centrally and spreads out. spares palms and soles.
Lyme disease: manifestations, transmission, tx
manifestations:
1. erythema chronicum migrans
2. CNS involvement (Bell’s palsy- distinguish from stroke by asking pts to raise eyebrows, aseptic meningitis, peripheral neuropathy); CV (carditis or AV block), secondary lesions, migratory myalgias and transient arthritis
3. chronic arthritis, encephalopathy.
carried by mice and spread by the Ixodes tick.
tx: doxycycline for stage 1.
ceftriaxone for later stages, esp. those with cardiac or neuro involvement.
mycoplasma pneumoniae: presentation, dx,
causes atypical pneumonia with insidious onset, non-productive cough, and a diffuse patchy infiltrate. CXR often looks worse than the patient does. May cause transient anemia. most common in pts under 30 and in military recruits and prisons.
Dx: cold hemaglutination with IgM. The cold agglutinins can agglutinate or lyse RBCs. grown on Eaton agar with cholesterol. Bacteria have no cell wall.
tx: macrolide, doxycycline, or fluroquinolone
chlamydia trachomati serotypes; tx, special features of the bug
A-C: chronic conjunctivitis. seen especiallly in africa and causes blindness (ABC = africa, blindness, chronic)
D-K: urehtritis, PID, neonatal pneumonia, neonatal conjunctivitis, reactive arthritis
L1-L3: lymphogranuloma venereum: small, painless genital ulcers that progress to swollen, painful inguinal lymph nodes that
ulcerate
special features: obligate intracellular, cell wall lacks muramic acid. elementary bodies are infectious and enter via endocytosis; reticular bodies do replication. replicates within inclusion bodies.
tx: one time azithromycin; doxycycline for lymphogranuloma venereum.
chlamydia pneumoniae: disease, treatment
causes atypical pneumonia. community acquired. has the elementary body and the reticular body just like C. trachomatis. tx: doxycyline
treponema pallidum: presentation
primary: painless chancer
secondary: condyloma lata (warty stuff on genitals), meningitis, arthritis, maculopapular rash on palms and soles.
tertiary: gummas, aortitis, tabes dorsalis, argylle robertson pupil.
congenital: CN VIII deafness, mulberry molars, saber shins, saddle nose, and hutchinson’s incisors. usually transmitted after the 1st trimester.
treponemia diagnosis and false positives; treatment
dark field microscopy, VDRL that detects abs against cardiolipin or RPR, FTA-ABS (specific antibodies against treponema)
VDRL false positives: mono, hepatitis, drugs, rhematic fever, lupus, leprosy
tx: penicillin G
Jarish-Herxheimer rxn
lysis of teponeme due to treatment causes release of endotoxin-like factors and fever, chills, and myalgias.
coxiellar burnetti: disease, spread, dx, tx
causes Q fever: an atypical pneumonia. No rash.
this is a type of rickettsia.
often seen in ppl with contact with cattle, sheep, or goats, esp. cattle placenta. survives as a spore and is inhaled. No arthropod vector (unlike other rickettsia).
Weil-Felix test is negative (unlike other rickettsia).
tx: doxycycline.
leptospira interrogans
causes:
1. leptospirosis: flu, jaundice, and photophobia
2. weil’s syndrome: a vasculitis that causes jaundice and azotemia from liver and kidney dysfunction, fever, hemorrhage, and anemia.
spread by water contaminated with animal urine. often seen in tropics and surfers.
this is a spirochete disorder
treat with penicillin G.
TB virulence factor and TB lung diseases; dx.
cord factor inhibits macrophage maturation and induces release of TNF-alpha.
sulfatides inhibit phaoglysosomal fusion.
may detect Gohn complex (calcified pulmonary tubules + hilar lymph nodes). may stread to other sites by lymphatics and blood.
can also look at IFN-gamma released by lymphocytes exposed to MTB antigens (quantiferon Gold assay)
common extra-pulmonary sites of TB
CNS, vertebral bodies, kidneys, GI, pericarditis, lymph ndues
