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
Bartonella heneslae
CAT SCRATCH DISEASE/FEVER
small pleomorphic G- rod
does NOT grow on blood agar
CAT SCRATCH or BITE, cat FLEAS
CHILDREN
self-limiting in immunocompetent
Sx: fever, enlarged nodes on side of scratch, papule at site of bite, resolves on own, endocarditis, encephalitis
AIDS: BACILLARY ANGIOMATOSIS in skin and visceral organs
Dx: serology, tissue biopsy: WARTHIN-STARRY silver stain, pathologic examination of angioma to rule out Kaposi
Tx: none, AZITHROMYCIN in seere lymphadenitis, doxycycline, erythromycin
Bacillus anthracis
anthrax
nonmotile G+ rod: BOXCAR
CAPSULE of d-GLUTAMATE (plasmid encoded), toxins
cattle, sheep, ANIMAL PRODUCTS: wool (WOOLSORTER’S disease)
GI
cutaneous: incubation hours to days, painless lesion with EDEMA becomes blistered and NECROTIC center develops, dizzy, heart palpitations, lymphangitis, can disseminate to lungs
lungs (serious): MEDIASTINAL WIDENING
untreated: FATAL
Dx: bacteria in a sample (blood, skin lesion, spinal fluid, resp. secretions), Ab/toxin in blood
Tx: CIPROFLOXACIN for 60 days (SPORES survive in macrophages)
Tx in severe: IV ciprofloxacin with one of the following: PCN, ampicillin, meropenem, rifampin, vancomycin
Burkholderia pseudomallei
MELIOIDOSIS/ WHITMORE’S DISEASE
can remain DORMANT for years: Vietnamese time bomb, short incubation possible
motile G- rod, INTRACELLULAR (macrophages)
CAPSULE, LPS, type 3/6 secretion, flagella, pili, proteins for invasion, lysis of host cell, uses host ACTIN to move into adjacent cells without being in ECM
ASIA: Thailand, N. Australia
soil, rice paddies, muddy water, sheep, goats, horses, swine
cutaneous: contact through abrasions, can disseminate to lungs
GI
lungs: most common and serious
Sx: fever, headache, ANOREXIA, muscle soreness, CHEST PAIN, COUGH
CXR: small nodule, consolidation of upper lobe, cavities
Dx: isolation in blood, urine, sputum, skin lesion, Ab in serum
Tx: CEFTAZIDIME (8 weeks, 6 mo. for immunocompromised), resistance to many antibiotics helps in Dx
Francisella tularensis
TULAREMIA/RABBIT FEVER/TICK FEVER, etc.
TICK, mites, lice, BLOOD to blood contact wit animal, inhale, ingest
YARD WORK: mow over RABBIT carcass; HUNTER
lives in AMOEBA
small pleomorphic G- rod, intracellular and extracellular
AR, MO, MA (Martha’s Vineyard)
type A: US, more virulent
type B: Europe
LPS not recognized by TLR-4, capsule (innate immune response, reduced innate cytokine production)
skin: ULCERGLANDULAR, can disseminate to lung
less common: glandular, oculoglandular, GI, PNA: high mortality
CXR: spotted infiltrates, pleural exudation, lobular PNA
Sx: rapid onset of flu-like Sx, LAD
Dx: AGGLUTINATION test, FLUORESCENT Ab
vaccine: military
Tx: STREPTOMYCIN
Yersinia pestis
PLAGUE/BLACK DEATH
FLEA from rodent, inhalation (fatal)
southeast ASIA, WEST US
small G- rod
CAPSULE, LPS, YOPS, intracellular
low ID50 (very virulent)
BIPOLAR staining: SAFETY PIN
Sx: BUBOES (inguinal LAD), DIC, cutaneous hemorrhage, flu-like, fatigue/collapse, bloody sputum, PNA
cutaneous can spread to lungs
Dx: blood/ buboes smear/culture, safety pin on Geimsa/Wayson stain, fluorescent Ab, Ab to envelope antigen in serum
Tx: STREPTOMYCIN and/or TETRACYCLINE (treat ASAP, don’t wait for confirmation)
Yops
Yersinia pestis outer proteins
injected by type 3 secretion
inhibit phagocytosis and host cytokine production
LPS
endotoxin that interferes with normal cytokine production by various cell types that respond to infection
in Yersinia: DIC, cutaneous hemorrhages
TH1
intracellular pathogens
CTL mediated host cell killing
vascular endothelial cell damage
