92 Microbiology II p186-p193
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- Neisseria
- p. 186
- Gram-negative cocci
- both
- Polysacharide capsule
- Meningococci
- Neonatal conjunctivitis
- Gonococci
- Vaccine available
- Meningococci
- Gonorrhea
- Gonococci
- Meningitis w/ septicemia
- Meningococci
- Waterhouse - Friederichsen syndrome
- Meningococci
- Septic arthritis
- Gonococci
- PID
- Gonococci
- Maltose fermentation
- Meningococci
- Primary and Secondary TB (figure)
- p. 187
- What is primary TB?
- Reponse to TB infection by a non-immune host, consists of hilar node involvement and Ghon focus
- What are possible outcomes of primary TB?
- Healing by fibrosis (characterized by hypersensitivity w/ PPD+), progressive lung disease (ass. W/ HIV, malnutrition), severe bacteremia (leading to miliary TB and death), preallergic lymphatic or hematogenous dissemination (leads to dormant tubercle bacilli in several organs and reactivation in adult life)
- What is secondary TB?
- Response to reinfection by a partially immune hypersensitized host (usu adult) OR reactivation of dormant tubercle bacilli from primary infection -- consists of fibrocaseous cavitary lesion
- What organs are commonly effected by extrapulmonary TB?
- CNS (parenchymal tuberculoma or meningitis), vertebral body (Pott's disease), lymphadenitis, renal, GI
- Mycobacteria
- p. 187
- What are common symptoms of TB?
- Fever, night sweats, weight loss, hemoptysis
- T/F: All mycobacteria are acid-fast
- TRUE
- T/F: M. Tuberculosis and M. avium-intracellulare can be resistant to multiple drugs
- TRUE
- T/F: M. kansasii is asymptomatic
- False: causes pulmonary TB-like symptoms
- T/F: M. scrofulaceum commonly causes cervical lymphadenitis in the elderly
- False: usually causes cervical lymphadenitis in kids
- Leprosy (Hansen's disease)
- p. 187
- What organism causes leprosy?
- Mycobacterium leprae
- T/F: M. leprae is an acid-fast bacterium that grows well in vitro
- False - M. leprae does not grow in vitro
- M. leprae likes ___ temperatures and infects ___ and ___ (tissues)
- cool, skin, superficial nerves
- What are the two forms of Hansen's disease? Which form is worse?
- Lepromatous and tuberculoid, tuberculoid is self-limited, lepromatous is worse (failed cell-mediated immunity) "LEpromatous = LEthal"
- What is wrong with armadillos?
- Resevoir of leprosy in U.S.
- What is treatmet for leprosy and associated toxicities?
- Long-term oral dapsone, toxicity = hemolysis and methemoglobinemia. Alternate treatments include rifampin and combination of clofazimine and dapsone.
- Ricketsia
- p188
- What is the classic triad of Rickettsial infection?
- headache, fever, rash
- True/False: Ricketsia are facultative intracellular parasites
- False, they are obligate parasites and need CoA and NAD
- Most Ricketsia are transmitted by what?
- arthropod vector
- Why is Coxiella an atypical ricketsia?
- It is transmitted by aerosol and causes pneumonia and no rash. Has negative Weil-Felix test.
- What is the treatment of choice for rickettsial infection?
- Tetracycline
- Rickettsial diseases and vectors
- p188
- What bug causes Rocky Mountain spotted fever? What is the vector?
- Rickettsia rickettsii, tick vector
- What bug causes Endemic typhus? What is the vector?
- Rickettsia typhi, flea vector
- What bug causes Epidemic typhus? What is the vector?
- Rickettsia prowazeckii, human body louse
- What bug causes Q fever? What is the vector?
- Coxiella burnetii, only rickettsial disease without a vector
- Rocky Mountain spotted fever
- p188
- What three diseases have characteristic palm and sole rash?
- Rocky Mountain spotted fever, syphilis, and coxsackievirus A16 (hand, foot, and mouth disease)
- How does the rash of Rocky Mountain spotted fever progress?
- centripetally, starting on palms and soles, migrating to wrists/ankles, then trunk
- What are the symptoms of Rocky Mountain spotted fever? What is the causative agent?
- Classic triad of rickettsial disease-headache, fever, rash. Rickettsia rickettsii
- Where is Rocky Mountain spotted fever common?
- Endemic to EAST coast
- Weil-Felix reaction
- p188
- What does the Weil-Felix reaction assay for?
- antirickettsial antibodies using cross reactivity with Proteus antigen.
- Which rickettsia test positive with Weil-Felix? Which test negative?
- typhus (R. typhi and R. prowazekii) and Rockey Mountain spotted fever (R. rickettsii) are usually positive. Q fever (C. burnetii, the weird one) is usually negative.
- Mycoplasma pneumonia
- p188
- Mycoplasma pneumonia causes what type of infection? Describe the symptoms. Which age group is it most common in?
- Classic cause of atypical "walking" pneumonia. Insidious onset, headache, nonproductive cough, diffuse interstitial infiltrate. More common in patients under 30.
- How does an X-ray appear in a Mycoplasma infection?
- Streaky, much worse than the patient appears.
- What is special about the mycoplasma cell wall?
- Only bacterial membrane containing cholesteral
- What can you test for in the blood of patient with Mycoplasma?
- They have high titers of cold agglutinins (IgM)
- Why can't you treat Mycoplasma infection with penecillin? What can you use?
- Mycoplasma has no cell wall. Use tetracycline or erythromycin
- What agar is Mycoplasma grown on?
- Eaton's
- Chlamydiae
- p189
- True/False: Chlamydia is an obligate intracellular parasite.
- TRUE
- Chlamydiae infects which type of surface?
- Mucosal
- How many forms does Chlamydia have? Describe them.
- Two: Elementary body, small/dense (Enters cell) and Initial/Reticulate body (Replicates by fusion)
- What is unusual about Chlamydia's cell wall?
- The peptidoglycan wall lacks muramic acid.
- What 4 things does Chlamydia cause?
- arthritis, conjunctivitis, pneumonia, and nongonococcal urethritis
- How do you diagnose a chlamydial infection? How do you treat it?
- cytoplasmic inclusions seen on Giemsa or fluorescent antibody-stained smear. Use erythromycin or tetracyclin
- Why is Chlamydia psittaci notable?
- Has an avian reservoir
- What species of animals do Chlamydia trachomatis and Chlamydia pneumonia infect? What do they cause?
- They only infect humans. C. trachomatis causes arthritis. C. pneumonia causes atypical pneumonia; transmitted by aerosol.
- Chlamydia trachomatis serotypes
- p. 189
- What are the serotypes of chlamydia?
- A - K, L1 - 3
- What do types A, B, C cause?
- chronic infection; blindness in Africa (Africa/Blindness/Chronic infection
- What do L1 - L3 cause?
- L = Lymphogranuloma venereum (acute lymphadenitis - positive Frei test)
- What do type D - K cause?
- everything else!! --> urethritis/PID, ectopic pregnancy, neonatal pneumonia, or neonatal conjunctivitis
- How is neonatal chlamydia aquired?
- passage through infected birth canal
- How is neonatal chlamydia treated?
- erythromycin eye drops
- Spirochetes
- p. 189
- Describe the shape of a spirochete.
- Spiral shaped bacteria with axial filaments
- Name the three major spirochetes.
- Borrelia (big size), Leptospira, Treponema (BLT. B is Big)
- Which can be identified by light microscopy using aniline dyes (Wright or Giemsa)?
- Borrelia (big size)
- How is Treponema visualized?
- dark-field microscopy
- Lyme disease
- p. 190
- What is the classic symptom of Lyme dz and how is it characterized?
- erythema chronicum migricans (an expanding "bull's eye" red rash with central clearing.
- What else does Lyme dz affect?
- joints, CNS, heart
- What are the Sx of Stage 1 Lyme dz?
- erythema chronicum migricans, flu-like sx
- What are the Sx of Stage 2 Lyme dz?
- neurologic and cardiac manifestations
- What are the Sx of Stage 3 Lyme dz?
- autoimmune migratory polyarthritis
- What causes Lyme disease and how is it transmitted?
- Borrelia burgdorferi, by the Ixodes tick.
- What are important reservoirs?
- Mice
- What animal is required for the life cycle?
- Deer
- How do you treat Lyme disease?
- Tetracycline
- Where in the US is Lyme disease common?
- northeast (named after Lyme, Connecticut)
- During what time of year is transmission most common?
- summer months
- Treponemal disease
- p. 190
- Treponemes are what type of organism?
- spirochetes
- What causes syphillis?
- Treponema pallidum
- What causes yaws?
- Treponema pertenue
- What is yaws?
- a tropical infection that is not an STD (although, VDRL test is positive)
- Syphilis
- p190
- What causes syphilis?
- Treponema pallidum, a spirochete
- What is characteristic of primary syphilis?
- A painless chancre (localized disease)
- What is characteristic of secondary syphilis?
- Constitutional symptoms, maculopapular rash, and condylomata lata.
- What is characteristic of end state syphilis?
- Gummas, aortitis, neurosyphilis (tabes dorsalis), Argyll Robertson pupil.
- What do you treat syphilis with?
- Penicillin G
- VDRL vs. FTA-ABS
- p190
- What do VDRL and FTA-ABS test for? Which is better and why?
- treponemes (syphilis), FTA-ABS is more specific, turns positive earlier and stays positive longer.
- VDRL false posititves
- p190
- What does VDRL detect? What disease is it used for?
- Nonspecific antibody that reacts with beef cardiolipin. Used for diagnosis of syphilis.
- What false positives are detected with VDRL?
- viral infection (mononucleosis, hepatitis), some drugs, rheumatic fever, rheumatoid arthritis, SLE, and leprosy.
- Spores: fungal
- p. 191
- Most fungal spores are sexual or asexual?
- asexual
- How are coccidioidomycosis and histoplasmosis transmitted?
- inhalation of asexual spores
- What are asexual spores called?
- conidia (e.g. blastoconidia, arthroconidia)
- Candida albicans
- p. 191
- Is c. albicans infection local, systemic, or both?
- both
- What is the morphology of c. albicans in culture at 20 deg C?
- budding yeast with pseudohyphae
- What is the morphology of c. albicans in culture at 37 deg C?
- germ tubes
- What does "alba" mean?
- "White"
- What disease does c. albicans cause in immunocompromised patients?
- thrush in throat (neonates, steroids, diabetes, AIDS)
- What disease does c. albicans cause in IV drug users?
- endocarditis
- What disease does c. albicans cause s/p antibiotic tx?
- vaginitis
- What disease does c. albicans cause in people who wear diapers (i.e. babies)?
- diaper rash
- What is the treatment for superficial c. albicans infection?
- nystatin
- What is the treatment for serious systemic c. albicans infection?
- amphotericin B
- Systemic Mycoses
- p. 191
- Name 4 types of systemic mycoses.
- Coccidioidomycosis, Histoplasmosis, Paracoccidioidomycosis, Blastomycosis
- Name the Endemic location of Coccidioidomycosis.
- Southwestern United States, California.
- Why is the disease caused by Coccidioidomycosis called “valley fever?”
- Common in the San Joaquin Valley or desert (desert bumps) "valley fever"
- Name the Endemic location of Histoplasmosis.
- Mississippi and Ohio river valleys.
- What is a common form of transmission of Histoplasmosis.?
- Bird or bat droppings
- Is Histoplasmosis found intracellularly or extracellularly?
- Intracellular (frequently seen inside macrophages)
- Name the Endemic location of Paracoccidioidomycosis.
- Rural Latin America.
- What is special about ParacoccidioidomycosisÂ’ appearance?
- "Captain's wheel" appearance.
- Name the Endemic location of Blastomycosis.
- States east of Mississippi River and Central America.
- How does Blastomycosis reproduce?
- Big, Broad-Based Budding.
- What is a dimorphic fungus?
- Mold in soil (at lower temperature) and yeast in tissue (at higher/body temperature: 37°C) Cold=Mold; Heat=Yeast
- Which of the following are dimorphic: Coccidioidomycosis, Histoplasmosis, Paracoccidioidomycosis, Blastomycosis ?
- All except coccidioidomycosis, which is a spherule in tissue.
- What is the appropriate treatment for local infection with the systemic mycoses?
- Treat with fluconazole or ketoconazole for local infection
- What is the appropriate treatment for systemic infection with the systemic mycoses?
- Treat with amphotericin B for systemic infection.
- What acid fast bacterial disease can the systemic mycoses mimic?
- TB (granuloma formation)
- What is the appropriate agar to use for culturing of systemic mycoses?
- Culture on Sabouraud's agar.
- Cutaneous Mycoses
- p. 191
- What organism causes Tinea versicolor?
- Malassezia furfur. Causes hypopigmented skin lesions.
- What organism causes Tinea nigra?
- Cladosporium werneckii
- How do you treat Tinea versicolor?
- miconazole, selenium sulfide
- What part of the skin is infected by tinea nigra and how does it present?
- Infection of keratinized layers of skin. Appears as brownish spots
- How do you treat tinea nigra?
- sialicylic acid
- Concerning Tinea pedis, cruris, corporis, capitis, what does the lesion look like?
- Pruritic lesion wit central clearing resembling a ring.
- What organisms cause Tinea pedis, cruris, corporis, & capitis?
- Dermatophytes: Microsporum, Trichophyton, Epidermophyton
- Concerning Tinea pedis, cruris, corporis, capitis, what do you see in a KOH prep?
- Mold hyphae, not dimorphic
- Concerning Microsporium, what is the reservoir for this organism
- Pets
- How is Microsporum infetction treated?
- topical azoles
- Opportunistic fungal infections
- p. 192
- What organism is the cause of thrush in immunocomprornised?
- Candida albicans
- Other than thrush and vulvovaginitis, what other diseases can Candida albicans cause?
- Disseminated candidiasis (to any organ) & chronic mucocutaneous candidiasis
- What is the morphology of Candida albicans?
- Pseudohyphae + budding yeasts or Germ tubes at 37 degrees C
- What pulmonary disease is caused by Aspergillus fumigatus?
- lung cavity aspergilloina ("fungus ball"), invasive aspergillosis.
- What is the morphology of Aspergillus fumigatus?
- Mold with septate hyphae that branch at a V-shaped (45°) angle.
- Is Aspergillus fumigatus dimorphic?
- NO
- What diseases does the yeast Cryptocuccus neoformans cause?
- Cryptococcal meningitis, cryptococcosis.
- What is the morphology of Cryptocuccus neoformans?
- Heavily encapsulated yeast.
- Is Cryptocuccus neoformans dimorphic?
- No
- What type of budding pattern is seen in Cryptocuccus neoformans?
- Narrow-based unequal budding
- What natural environment is Cryptocuccus neoformans usually found?
- Found in soil, pigeon droppings.
- What do you culture Cryptocuccus neoformans on?
- Culture on Sabouraud's agar.
- What special stain is used for Cryptocuccus neoformans ?
- Stains with India ink.
- What special test does the capsule of Cryptocuccus neoformans allow you to do?
- Latex agglutination test detects polysaccharide capsular antigen
- What is the morphology of Mucor?
- Mold with irregular nonseptate hyphae branching at wide angles (> 90°).
- What immune modifying diseases (2) state is commonly associated with infection with Mucor?
- Disease mostly in ketoacidotic diabetic and leukemic patients.
- How does infection with Mucor lead to sympotms (pathogensis)?
- Fungi proliferate in the walls of blood vessels and cause infarction of distal tissue.
- Pneumocystis carinii
- p. 192
- What disease does Pneumocystis carinii cause?
- Causes pneumonia (PCP).
- What class of organism is Pneumocystis carinii?
- Yeast (originally classified as protozoan)
- How is Pneumocystis carinii transmitted to caused disease?
- Inhaled
- What predisposes to disease with Pneumocystis carinii?
- Most infections asymptomatic. Immunosuppression (e.g., AIDS) predisposes to disease.
- How do you stain for Pneumocystis carinii?
- Silver stain of lung tissue.
- How do you treat infection with Pneumocystis carinii?
- Treat with TMP-SMX, pentamidine.
- With regards to P. carinii, what should you do for an AIDS patient with CD4 below 200 cells/mL to prevent PCP?
- Start prophylaxis when CD4 drops below 200 cells/mL in HIV patients.
- Sporothrix schenckii
- p.192
- Where is Sporothrix schenckii normally found and how is it transmitted?
- Found on vegetation and transmitted by trauma to the skin, typically by a thorn ("rose gardener's" disease)
- What are the symptoms of Sporcitrichosis?
- Local pustule or ulcer with nodules along draining lymphatics. Little systemic illness.
- How do you treat Sporcitrichosis?
- Treat with itraconazole or potassium iodide.
- Medically important protozoa (from a table)
- p. 193
- Entamoeba histolytica
- p. 193
- What disease(s) does it cause?
- Rapidly fatal meningoencephalitis
- How is it transmitted?
- Swimming in fresh water lakes
- How is it diagnosed?
- Amebas in spinal fluid
- How it is treated?
- Giardia lamblia
- p. 193
- Cryptosporidium
- p. 193
- Toxoplasma
- p. 193
- Plasmodium
- p. 193
- What are the different species?
- P. vivax, P. ovale, P. malariae, P. falciparum
- Trichomonas vaginalis
- p. 193
- Trypanosoma cruzi
- p. 193
- Trypanosoma gambiense & rhodesiense
- p. 193
- Leishmania donovani
- p. 193
- Babesia
- p. 193
- Naegleria
- p. 193