Micro Final

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  1. Group A streptococcus (GAS)
    • -Spread through droplets
    • -M protein- antiphagocytic, antibodies causes rheumatic fever (type II hypersensitivity)
    • -Encapsulated
    • -Pyrogenic exotoxin (superantigen, scarlet fever)
    • -Degradative enzymes (ex. Hemolysins, DNAse)
    • -Rheumatic fever
    • -Scarlet fever
    • -Invasive disease (causes death)
    • -Treated with penicillin (to prevent rheumatic fever)
    • -Shotty lymphadenopathy
    • -Common in 5-15 year olds
    • -Late winter through early spring
  2. Streptococcus pneumoniae
    • -Spread through droplets
    • -Colonize upper respiratory tract
    • -Productive cough, inflammation, pneumonia
    • -Antiphagocytic Capsule
    • -Pneumolysin- inflames epithelial and endothelial cells, pneumonia -Penicillin (increasing resistance)
    • -Macrolides and TMP/SMX (increasing resistance)
    • -Treated with 13 valent conjugated vaccine
    • -Common in day care attendees
  3. Influenza
    • -RNA virus
    • -3 types: A,B,C
    • -Non-productive cough, headache, fever, body aches
    • -HA (hemaglutinin)- cleaved by host cell, important in viral attachment and entry into host cells - fusion activity.
    • -NA (neuraminidase), cleaves sialic acid residues from the host cell receptor to release virus particles
    • -Defect in ciliary function can cause secondary bacterial infection
    • -Antigenic drift- gradual point mutations in receptors, causes different strains in humans
    • -Antigenic shift- recombination of strains between species, major change in RNA segments. Influenza B does not shift
    • Treated with:
    • -Amantadine (inhibits viral uncoating, only active against A)
    • -Neuraminidase inhibitors (viral particles not released)
    • -Tamiflu- M2 inhibitor
    • -Oseltamivir or Zanamivir
    • -Flu vaccines (shots or live attenuated) .
  4. Mycobacterium tuberculosis
    • -Spread through aerosols, slow growing
    • -Strict aerobes
    • -Taken up by macrophage, multiplies over 3 weeks within the macrophage
    • -Causes granulomas (bacteria surrounded by inflammatory immune cells)
    • -Ghon complex legion (latent stage)
    • -Can relapse in immunocompromised individuals (granuloma becomes liquid, bacteria gets free)
    • -Fever, night sweats, cough and hemopytis (blood in sputum)
    • -Death in immunocompromised
    • -90% of infected individuals are asymptomatic
    • -Immigrants, poor, homeless, prisoners at higher risk
    • -Treated with isoniazid, rifampin, fluoroquinolone
  5. Rickettsia rickettsii
    • -Gram (-) obligate intracellular bacterium, uses host ATP
    • -Enters bloodstream via ticks
    • -Endocytosed by endothelial cells
    • -Escapes phagosome (like Listeria)
    • -Replicates in cytoplasm of endothelial cells,
    • -Uses host actin for motility
    • -Breaks apart endothelial cells which line blood vessels, causes spotted pattern on skin (blood leakage, hypovolemic shock, hyponatremia)
    • -Rocky mountain spotted fever (spotted rash on skin)
    • -headache and photophobia
    • -Most active between April and September
    • -Treated with Doxycycline
    • -Resistant to beta-lactams, aminoglycosides, macrolides, and TMP/SMX
  6. Malaria
    • -Plasmodium falciparum (or vivax, ovale, malariae, knowlesi)
    • -Vector borne (mosquito), obligate intracellular
    • -Infect liver cells and red blood cells
    • -Adhesion to capillary walls, inflammation
    • -Vector control important
    • -Prevented/treated with prophylactic antimicrobials
    • -Mefloquine, Malorone, Doxycycline, Chloroquine, Primaquine -High fever, chills, headache, nausea
    • -Severe malaria (coma, anemia, death)
    • -Low birth weight
    • -High immunity in sub-Saharan Africa
  7. Dengue Virus (Flavivirus)
    • -Vector borne (mosquito) enveloped RNA virus
    • -Primary infection- either asymptomatic or causes Dengue fever/hemorrhagic fever
    • -Secondary infection- may cause Dengue shock syndrome
    • -hypovolemic shock, thrombocytopenia
    • -No vaccine or antivirals, vector control important
  8. EHEC (Enterohemorrhagic E. Coli)
    • -Food and water borne (fecal-oral route)
    • -Undercooked hamburger, beverages, plants
    • -Person to person spread in daycare
    • -Watery diarrhea that becomes bloody
    • -Shiga AB toxin (O157:H7)- inhibits protein synthesis, cytokine reaction causes bloody diarrhea
    • -Pili associated with intimin- tight binding to epithelial cell
    • -ORT, isotonic solutions
    • -Antibiotics likely to cause damage
    • -Tends to affect young and old
  9. Campylobacter
    • -Gram (-) microaeropile
    • -Acquired from contaminated food or water
    • -Animal contact/ undercooked poultry
    • -Infectious dose~10,000 organisms (acid sensitive)
    • -Multiply in small intestine lumen, invade epithelium
    • -Endotoxic LPS and exotoxins
    • -Host factors play a role in virulence
    • -Treated with ORT
    • -Do not mix raw meat and vegetables
    • -In very sick patients: azithromycin or ciprofloxacin
    • -Bloody diarrhea
    • -Abdominal pain
    • -WBCs in stool
    • -Guillan-Barre syndrome
  10. Norovirus
    • -Fecally contaminated food or water, or direct contact (aerosols)
    • -Highly contagious RNA virus
    • -Stable in environment
    • -Enterotoxins- induce fluid secretion in the gut
    • -Replication kills cells on villi, malabsorptive, watery diarrhea
    • -Treated with ORT
    • -Causes muscle aches, chills/fever, headache, nausea
    • -Large scale outbreaks (schools, cruise ships, etc)
    • -Up to 30% asymptomatic
  11. Giardia trophozoite
    • -Parasite
    • -Infective, resistant cysts in food and fomites
    • -Adhere to small intestine via sucking disks
    • -Disrupts intestinal brush border, disacchridase deficiencies
    • -Treated with ORT
    • -Filter cysts out of water
    • -Cause chronic or acute diarrhea
    • -Chronic: malabsorptive fatty, foul smelling stools
    • -Acute: watery, self-limited
    • -Nausea, abdominal pain
  12. Meningitis
    • -Septic- caused by bacteria
    • -Aseptic- not caused by bacteria
    • -Nisseria meningitides spread by droplet
    • -Encapsulated bacteria
    • -Bind to endothelial cell receptors
    • -Must cross the blood-brain barrier
    • -Conjugated vaccines for Haemophilus influenza B,
    • Neisseria meningitides, and Streptococcus pneumonia have caused a decline, chemoprophylaxis also used
    • -Causes disseminated intravascular coagulation (DIC)
    • -Hemorrhages, hemoptysis, headache, photophobia
    • -Neurocystercerosis obtained from food/water contaminated with human feces
    • Aseptic if patient does not have:
    • -Gram stain positive for bacteria
    • -High neutrophil count
    • -Low glucose
    • -High protein
    • -History of seizure
  13. Group B Streptococcus
    • -Infection in infants without prenatal care
    • -Early onset- targets the lung in first 3 days of life, high mortality
    • -Late onset- between a week and 2 months, bacteremia and meningitis, lower mortality
    • -Prophylaxis given to Group B Strep positive women prenatally
    • -Vaginorectal screenings
    • -Treated with Ampicillin and Clindamycin
  14. Treponema pallidum
    • -Spirochete STI
    • -Also transmitted vertically
    • -Secondary syphilis spread by skin-skin contact
    • -RPR- primary screen, sensitive, measures antibodies to cardiolipin (released from damaged cells)
    • -TPPA- secondary test, measures T pallidum specific antibodies
    • -Primary syphilis- causes a chancre
    • -Secondary- 1-2 months after, rash prominent on palms and feet
    • -Tertiary- 20-40 yrs after infection, granulomatous
    • -Severe syphilis- cardiovascular and neurologic manifestations
    • -Very responsive to various antimicrobials
  15. Neisseria gonorrhoeae
    • -Gram (-) STI
    • -Vertical transmission possible
    • -Pilin- attaches to urethral epithelium
    • -LPS responsible for tissue damage
    • -IgA protease - degrades secretory IgA
    • -Endocytosed into epithelial cels, endotoxins cause inflammation -Urethral discharge
    • -Treated with IM ceftriaxone
    • -Patients should also be treated for chlamydia
  16. Chlamydia
    • -obligate intracellular pathogen
    • -frequently asymptomatic
    • -causes pelvic inflammatory disease (PID),
    • -treated with azithromycin or doxycycline
  17. HPV (Human Papilloma Virus)
    • -very common, associated with genital warts,
    • -can lead to cervical cancer
    • -vaccine available
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Micro Final
2013-06-26 02:29:54
Micro Final

Micro Final
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