Micro: Miller Flashcards
Rickettsia and related microbes
includes: Rickettsia, Ehrlichia, coxiella very short rods, INTRACELLULAR gram stains work poorly similar to G- lesion VASCULITIS causing skin RASH ENDOTOXIN no exotoxins or cytolytic enzymes begin with FLU LIKE symptoms
Rickettsia rickettsii
ROCKY MOUNTAIN SPOTTED FEVER
TICKS on mammals (DOGS), children in spring/summer
GA, NC, VA
Sx: muscle soreness in CALVES, RASH with macule progressing to petechiae (vascular endothelial cells) starts at ANKLES, WRISTS and spreads to trunk/PALMS/SOLES, DELIRIUM, COMA
CTL mediated host cell killing
severe: DIC, edema, circulatory collapse
FATAL if not treated
Dx: clinical, serology, Weil-Felix, indirect immunofluorescent assay
Tx: doxycycline (ASAP)
Weil-Felix test
non-specific
detects anti-rickerrsial Ab in serum (react with Proteus antigens)
Rickettsia prowazekii
EPIDEMIC TYPHUS
flying squirrels, LICE FECES
not in US
rash spreads from TRUNK to extremities, NOT found palms/soles
high mortality: bacterial pneumonia, vascular collapse
Sx: MYOCARDITIS, CNS
Dx: IFA, ELISA (4 fold increase between acute phase and convalescence is diagnostic)
Tx: doxycycline, tetracycline; chloramphenicol
Rickettsia typhi
ENDEMIC (MURINE) TYPHUS RAT FLEA: small mammals: RATS, OPOSSUM LOW MORTALITY even if untreated Sx: rash, mild Dx: clinical and ELISA Tx: doxycycline
Ehrlichia chaffeensis
HUMAN MONOCYIC EHRLICHIOSIS LONE STAR DEER TICK MORULAE in MONOCYTES Sx: CONJUNCTIVAL INJECTION, rash Dx: BLOOD SMEAR, serology confirmation: PCR Tx: doxycycline
Anaplasma (Ehrlichia) phagocytophilia
HUMAN GRANULOCYTIC ANAPLASMOSIS: rocky mountain spotless fever
IXODES TICKS
MORULAE in GRANULOCYTES (TH1)
Sx: confusion
severe: difficulty breathing, hemorrhage, renal failure, neurological problems
Dx: BLOOD SMEAR
Tx: doxycycline
if rash is present: co-infection with B. burgdorferi
Coxiella burnetii
Q FEVER G- bacillus, INTRACELLULAR CATTLE, SHEEP, GOATS (west US, agricultural areas): contaminated viscera, raw milk TICK in MACROPHAGES very infectious inhaled SPORE: most serious disease Sx: none, can resolve on own, PNA chronic infection: ENDOCARDITIS, GRANULOMATOUS HEPATITIS, untreated: FATAL Dx: serology (Q Ab) Tx: none or doxycycline
Borrelia burgdorferi
LYME DISEASE
SPIROCHETE
IXODES SCAPULARIS
small mammals: WHITE FOOTED MOUSE
EAST COAST, MIDWEST: NY, CT, PA, NJ in summer
west coast: Ixodes pacificus; outside US: I. ricinus/persulcatus
negative cultures in humans, positive culture in tick
bite causes bacteremia in HEART, JOINTS, CNS
OSPs
Dx: ELISA (sensitive), must confirm with WESTERN BLOT, PCR
Early Tx: doxycycline, tetracycline, amoxicillin
Chronic Tx: IV CEPHALOSPORIN or PCN G
how do you look at spirochetes?
darkfield microscopy, Giemsa or silver stain
OSPs (outer surface proteins)
Borrelia
antigenic variation allow to survive in different hosts: mouse, human, tick, etc.
Stages of Lyme disease
1: acute lyme disease: erythema chronicum migrants (BULLS EYE), flu-like, ARTHRALGIA, skin lesions
2: weeks/months later: cardio/neuro involvement: MYOCARDITIS (heart block), BILATERAL BELL’S PALSY, acute MENINGITIS
3: chronic: ARTHRITIS of large joints (autoimmune), chronic progressive CNS disease
Borrelia hermsii
RELAPSING FEVER SPIROCHETE IXODES TICK antigenic variation of OSPs allows fever to come back Dx: BLOOD SMEAR Tx: tetracycline, doxycycline
Borrelia recurrentis
RELAPSING FEVER SPIROCHETE LICE antigenic variation of OSPs allows fever to come back Dx: BLOOD SMEAR Tx: tetracycline, doxycycline
Leptospira interrogans
SPIROCHETE
LEPTOSPIROSIS: cutaneous or mucosal
various animals: DOG URINE contaminates water/soil
SWIMMING, DRINKING: triathlon, sewer, farmer, miner
URBAN POOR
liver, kidneys, lungs, CNS
BIPHASIC: break between
early Sx: flu-like, CONJUNCTIVITIS
late Sx: MENINGITIS, LIVER damage (JAUNDICE), KIDNEY (UREMIA, Weil’s disease), LUNG HEMORRHAGE
Dx: Hx of exposure, clinical , IgM, isolation unreliable
Tx: PCN G
vaccine: pets and livestock
