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***usmle 2408-2608 micro 2

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Zoonotic Bacteria: Name 5 common zoonotic bacteria
Bugs from your pet: Borrelia burgdorferi, Brucella, Francisella tularensis, Yersinia pestis, Pasteirella multocida
Name the disease, mode of transmission, and source associated with the following:: Borrelia burgdorferi
Lyme disease; tick bite; Ixodes ticks that live on deer and mice
Name the disease, mode of transmission, and source associated with the following:: Brucella
Brucellosis/undulant fever; dairy products, contact with animals -- "Undulate and Unpasteurized products give you Undulant fever"
Name the disease, mode of transmission, and source associated with the following:: Francisella tularensis
Tularemia; tick bite; rabbits, deer
Name the disease, mode of transmission, and source associated with the following:: Yersenia pestis
Plague, flea bite; rodents, esp. prarie dogs
Name the disease, mode of transmission, and source associated with the following:: Pasteurella multocida
Cellulitis; animal bite; cats, dogs
Gardnerella vaginalis: What symptoms are associated with G. vaginalis infection?
Vaginosis - greenish vaginal discharge, fishy smell, not painful
Gardnerella vaginalis: What is Mobiluncus?
An anaerobe commonly involved in G. vaginalis infections
Gardnerella vaginalis: G. vaginallis should be treated with ___
Metronidazole
Gardnerella vaginalis: What are the laboratory characteristics of G. vaginalis?
Pleiomorphic, gram-variable rod; clue cells - vaginal epithelial cells covered with bacteria are visible under a microscope
Identify as associated with Meningococci, Gonococci, or both:: Gram-negative cocci
both
Identify as associated with Meningococci, Gonococci, or both:: Polysacharide capsule
Meningococci
Identify as associated with Meningococci, Gonococci, or both:: Neonatal conjunctivitis
Gonococci
Identify as associated with Meningococci, Gonococci, or both:: Vaccine available
Meningococci
Identify as associated with Meningococci, Gonococci, or both:: Gonorrhea
Gonococci
Identify as associated with Meningococci, Gonococci, or both:: Meningitis w/ septicemia
Meningococci
Identify as associated with Meningococci, Gonococci, or both:: Waterhouse - Friederichsen syndrome
Meningococci
Identify as associated with Meningococci, Gonococci, or both:: Septic arthritis
Gonococci
Identify as associated with Meningococci, Gonococci, or both:: PID
Gonococci
Identify as associated with Meningococci, Gonococci, or both:: Maltose fermentation
Meningococci
Primary and Secondary TB (figure): What is primary TB?
Reponse to TB infection by a non-immune host, consists of hilar node involvement and Ghon focus
Primary and Secondary TB (figure): What are possible outcomes of primary TB?
Healing by fibrosis (characterized by hypersensitivity w/ pD+), 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)
Primary and Secondary TB (figure): 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
Primary and Secondary TB (figure): What organs are commonly effected by extrapulmonary TB?
CNS (parenchymal tuberculoma or meningitis), vertebral body (Pott's disease), lymphadenitis, renal, GI
Mycobacteria: What are common symptoms of TB?
Fever, night sweats, weight loss, hemoptysis
Mycobacteria: T/F: All mycobacteria are acid-fast
TRUE
Mycobacteria: T/F: M. Tuberculosis and M. avium-intracellulare can be resistant to multiple drugs
TRUE
Mycobacteria: T/F: M. kansasii is asymptomatic
False: causes pulmonary TB-like symptoms
Mycobacteria: T/F: M. scrofulaceum commonly causes cervical lymphadenitis in the elderly
False: usually causes cervical lymphadenitis in kids
Leprosy (Hansen's disease): What organism causes leprosy?
Mycobacterium leprae
Leprosy (Hansen's disease): T/F: M. leprae is an acid-fast bacterium that grows well in vitro
False - M. leprae does not grow in vitro
Leprosy (Hansen's disease): M. leprae likes ___ temperatures and infects ___ and ___ (tissues)
cool, skin, superficial nerves
Leprosy (Hansen's disease): 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"
Leprosy (Hansen's disease): What is wrong with armadillos?
Resevoir of leprosy in U.S.
Leprosy (Hansen's disease): 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.
Leprosy (Hansen's disease): AUTHOR
Adam Weitzman, et al.
Ricketsia: What is the classic triad of Rickettsial infection?
headache, fever, rash
Ricketsia: True/False: Ricketsia are facultative intracellular parasites
False, they are obligate parasites and need CoA and NAD
Ricketsia: Most Ricketsia are transmitted by what?
arthropod vector
Ricketsia: Why is Coxiella an atypical ricketsia?
It is transmitted by aerosol and causes pneumonia and no rash. Has negative Weil-Felix test.
Ricketsia: What is the treatment of choice for rickettsial infection?
Tetracycline
Rickettsial diseases and vectors: What bug causes Rocky Mountain spotted fever? What is the vector?
Rickettsia rickettsii, tick vector
Rickettsial diseases and vectors: What bug causes Endemic typhus? What is the vector?
Rickettsia typhi, flea vector
Rickettsial diseases and vectors: What bug causes Epidemic typhus? What is the vector?
Rickettsia prowazeckii, human body louse
Rickettsial diseases and vectors: What bug causes Q fever? What is the vector?
Coxiella burnetii, only rickettsial disease without a vector
Rocky Mountain spotted fever: What three diseases have characteristic palm and sole rash?
Rocky Mountain spotted fever, syphilis, and coxsackievirus A16 (hand, foot, and mouth disease)
Rocky Mountain spotted fever: How does the rash of Rocky Mountain spotted fever progress?
centripetally, starting on palms and soles, migrating to wrists/ankles, then trunk
Rocky Mountain spotted fever: What are the symptoms of Rocky Mountain spotted fever? What is the causative agent?
Classic triad of rickettsial disease-headache, fever, rash. Rickettsia rickettsii
Rocky Mountain spotted fever: Where is Rocky Mountain spotted fever common?
Endemic to EAST coast
Weil-Felix reaction: What does the Weil-Felix reaction assay for?
antirickettsial antibodies using cross reactivity with Proteus antigen.
Weil-Felix reaction: 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: 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.
Mycoplasma pneumonia: How does an X-ray appear in a Mycoplasma infection?
Streaky, much worse than the patient apears.
Mycoplasma pneumonia: What is special about the mycoplasma cell wall?
Only bacterial membrane containing cholesteral
Mycoplasma pneumonia: What can you test for in the blood of patient with Mycoplasma?
They have high titers of cold agglutinins (IgM)
Mycoplasma pneumonia: Why can't you treat Mycoplasma infection with penecillin? What can you use?
Mycoplasma has no cell wall. Use tetracycline or erythromycin
Mycoplasma pneumonia: What agar is Mycoplasma grown on?
Eaton's
Chlamydiae: True/False: Chlamydia is an obligate intracellular parasite.
TRUE
Chlamydiae: Chlamydiae infects which type of surface?
Mucosal
Chlamydiae: How many forms does Chlamydia have? Describe them.
Two: Elementary body, small/dense (Enters cell) and Initial/Reticulate body (Replicates by fusion)
Chlamydiae: What is unusual about Chlamydia's cell wall?
The peptidoglycan wall lacks muramic acid.
Chlamydiae: What 4 things does Chlamydia cause?
arthritis, conjunctivitis, pneumonia, and nongonococcal urethritis
Chlamydiae: 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
Chlamydiae: Why is Chlamydia psittaci notable?
Has an avian reservoir
Chlamydiae: 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: What are the serotypes of chlamydia?
A - K, L1 - 3
Chlamydia trachomatis serotypes: What do types A, B, C cause?
chronic infection; blindness in Africa (Africa/Blindness/Chronic infection
Chlamydia trachomatis serotypes: What do L1 - L3 cause?
L = Lymphogranuloma venereum (acute lymphadenitis - positive Frei test)
Chlamydia trachomatis serotypes: What do type D - K cause?
everything else!! --> urethritis/PID, ectopic pregnancy, neonatal pneumonia, or neonatal conjunctivitis
Chlamydia trachomatis serotypes: How is neonatal chlamydia aquired?
passage through infected birth canal
Chlamydia trachomatis serotypes: How is neonatal chlamydia treated?
erythromycin eye drops
Spirochetes: Describe the shape of a spirochete.
Spiral shaped bacteria with axial filaments
Spirochetes: Name the three major spirochetes.
Borrelia (big size), Leptospira, Treponema (BLT. B is Big)
Spirochetes: Which can be identified by light microscopy using aniline dyes (Wright or Giemsa)?
Borrelia (big size)
Spirochetes: How is Treponema visualized?
dark-field microscopy
Lyme disease: 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.
Lyme disease: What else does Lyme dz affect?
joints, CNS, heart
Lyme disease: What are the Sx of Stage 1 Lyme dz?
erythema chronicum migricans, flu-like sx
Lyme disease: What are the Sx of Stage 2 Lyme dz?
neurologic and cardiac manifestations
Lyme disease: What are the Sx of Stage 3 Lyme dz?
autoimmune migratory polyarthritis
Lyme disease: What causes Lyme disease and how is it transmitted?
Borrelia burgdorferi, by the Ixodes tick.
Lyme disease: What are important reservoirs?
Mice
Lyme disease: What animal is required for the life cycle?
Deer
Lyme disease: How do you treat Lyme disease?
Tetracycline
Lyme disease: Where in the US is Lyme disease common?
northeast (named after Lyme, Connecticut)
Lyme disease: During what time of year is transmission most common?
summer months
Treponemal disease: Treponemes are what type of organism?
spirochetes
Treponemal disease: What causes syphillis?
Treponema pallidum
Treponemal disease: What causes yaws?
Treponema pertenue
Treponemal disease: What is yaws?
a tropical infection that is not an STD (although, VDRL test is positive)
Syphilis: What causes syphilis?
Treponema pallidum, a spirochete
Syphilis: What is characteristic of primary syphilis?
A painless chancre (localized disease)
Syphilis: What is characteristic of secondary syphilis?
Constitutional symptoms, maculopapular rash, and condylomata lata.
Syphilis: What is characteristic of end state syphilis?
Gummas, aortitis, neurosyphilis (tabes dorsalis), Argyll Robertson pupil.
Syphilis: What do you treat syphilis with?
Penicillin G
VDRL vs. FTA-ABS: 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: What does VDRL detect? What disease is it used for?
Nonspecific antibody that reacts with beef cardiolipin. Used for diagnosis of syphilis.
VDRL false posititves: What false positives are detected with VDRL?
viral infection (mononucleosis, hepatitis), some drugs, rheumatic fever, rheumatoid arthritis, SLE, and leprosy.
Spores: fungal: Most fungal spores are sexual or asexual?
asexual
Spores: fungal: How are coccidioidomycosis and histoplasmosis transmitted?
inhalation of asexual spores
Spores: fungal: What are asexual spores called?
conidia (e.g. blastoconidia, arthroconidia)
Candida albicans: Is c. albicans infection local, systemic, or both?
both
Candida albicans: What is the morphology of c. albicans in culture at 20 deg C?
budding yeast with pseudohyphae
Candida albicans: What is the morphology of c. albicans in culture at 37 deg C?
germ tubes
Candida albicans: What does "alba" mean?
White
Candida albicans: What disease does c. albicans cause in immunocompromised patients?
thrush in throat (neonates, steroids, diabetes, AIDS)
Candida albicans: What disease does c. albicans cause in IV drug users?
endocarditis
Candida albicans: What disease does c. albicans cause s/p antibiotic tx?
vaginitis
Candida albicans: What disease does c. albicans cause in people who wear diapers (i.e. babies)?
diaper rash
Candida albicans: What is the treatment for superficial c. albicans infection?
nystatin
Candida albicans: What is the treatment for serious systemic c. albicans infection?
amphotericin B
Systemic Mycoses: Name 4 types of systemic mycoses.
Coccidioidomycosis, Histoplasmosis, Paracoccidioidomycosis, Blastomycosis
Systemic Mycoses: Name the Endemic location of Coccidioidomycosis.
Southwestern United States, California.
Systemic Mycoses: Why is the disease caused by Coccidioidomycosis called “valley fever?”
Common in the San Joaquin Valley or desert (desert bumps) "valley fever"
Systemic Mycoses: Name the Endemic location of Histoplasmosis.
Mississipi and Ohio river valleys.
Systemic Mycoses: What is a common form of transmission of Histoplasmosis.?
Bird or bat dropings
Systemic Mycoses: Is Histoplasmosis found intracellularly or extracellularly?
Intracellular (frequently seen inside macrophages)
Systemic Mycoses: Name the Endemic location of Paracoccidioidomycosis.
Rural Latin America.
Systemic Mycoses: What is special about Paracoccidioidomycosis’ appearance?
Captain's wheel apearance.
Systemic Mycoses: Name the Endemic location of Blastomycosis.
States east of Mississipi River and Central America.
Systemic Mycoses: How does Blastomycosis reproduce?
Big, Broad-Based Budding.
Systemic Mycoses: 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
Systemic Mycoses: Which of the following are dimorphic: Coccidioidomycosis, Histoplasmosis, Paracoccidioidomycosis, Blastomycosis ?
All except coccidioidomycosis, which is a spherule in tissue.
Systemic Mycoses: What is the appropriate treatment for local infection with the systemic mycoses?
Treat with fluconazole or ketoconazole for local infection
Systemic Mycoses: What is the appropriate treatment for systemic infection with the systemic mycoses?
Treat with amphotericin B for systemic infection.
Systemic Mycoses: What acid fast bacterial disease can the systemic mycoses mimic?
TB (granuloma formation)
Systemic Mycoses: What is the appropriate agar to use for culturing of systemic mycoses?
Culture on Sabouraud's agar.
Cutaneous Mycoses: What organism causes Tinea versicolor?
Malassezia furfur. Causes hypopigmented skin lesions.
Cutaneous Mycoses: What organism causes Tinea nigra?
Cladosporium werneckii
Cutaneous Mycoses: How do you treat Tinea versicolor?
miconazole, selenium sulfide
Cutaneous Mycoses: What part of the skin is infected by tinea nigra and how does it present?
Infection of keratinized layers of skin. Apears as brownish spots
Cutaneous Mycoses: How do you treat tinea nigra?
sialicylic acid
Cutaneous Mycoses: Concerning Tinea pedis, cruris, corporis, capitis, what does the lesion look like?
Pruritic lesion wit central clearing resembling a ring.
Cutaneous Mycoses: What organisms cause Tinea pedis, cruris, corporis, & capitis?
Dermatophytes: Microsporum, Trichophyton, Epidermophyton
Cutaneous Mycoses: Concerning Tinea pedis, cruris, corporis, capitis, what do you see in a KOH prep?
Mold hyphae, not dimorphic
Cutaneous Mycoses: Concerning Microsporium, what is the reservoir for this organism
Pets
Cutaneous Mycoses: How is Microsporum infetction treated?
topical azoles
Opportunistic fungal infections: What organism is the cause of thrush in immunocomprornised?
Candida albicans
Opportunistic fungal infections: Other than thrush and vulvovaginitis, what other diseases can Candida albicans cause?
Disseminated candidiasis (to any organ) & chronic mucocutaneous candidiasis
Opportunistic fungal infections: What is the morphology of Candida albicans?
Pseudohyphae + budding yeasts or Germ tubes at 37 degrees C
Opportunistic fungal infections: What pulmonary disease is caused by Aspergillus fumigatus?
lung cavity aspergilloina ("fungus ball"), invasive aspergillosis.
Opportunistic fungal infections: What is the morphology of Aspergillus fumigatus?
Mold with septate hyphae that branch at a V-shaped (45°) angle.
Opportunistic fungal infections: Is Aspergillus fumigatus dimorphic?
NO
Opportunistic fungal infections: What diseases does the yeast Cryptocuccus neoformans cause?
Cryptococcal meningitis, cryptococcosis.
Opportunistic fungal infections: What is the morphology of Cryptocuccus neoformans?
Heavily encapsulated yeast.
Opportunistic fungal infections: Is Cryptocuccus neoformans dimorphic?
No
Opportunistic fungal infections: What type of budding pattern is seen in Cryptocuccus neoformans?
Narrow-based unequal budding
Opportunistic fungal infections: What natural environment is Cryptocuccus neoformans usually found?
Found in soil, pigeon dropings.
Opportunistic fungal infections: What do you culture Cryptocuccus neoformans on?
Culture on Sabouraud's agar.
Opportunistic fungal infections: What special stain is used for Cryptocuccus neoformans ?
Stains with India ink.
Opportunistic fungal infections: What special test does the capsule of Cryptocuccus neoformans allow you to do?
Latex agglutination test detects polysaccharide capsular antigen
Opportunistic fungal infections: What is the morphology of Mucor?
Mold with irregular nonseptate hyphae branching at wide angles (> 90°).
Opportunistic fungal infections: What immune modifying diseases (2) state is commonly associated with infection with Mucor?
Disease mostly in ketoacidotic diabetic and leukemic patients.
Opportunistic fungal infections: 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: What disease does Pneumocystis carinii cause?
Causes pneumonia (PCP).
Pneumocystis carinii: What class of organism is Pneumocystis carinii?
Yeast (originally classified as protozoan)
Pneumocystis carinii: How is Pneumocystis carinii transmitted to caused disease?
Inhaled
Pneumocystis carinii: What predisposes to disease with Pneumocystis carinii?
Most infections asymptomatic. Immunosupression (e.g., AIDS) predisposes to disease.
Pneumocystis carinii: How do you stain for Pneumocystis carinii?
Silver stain of lung tissue.
Pneumocystis carinii: How do you treat infection with Pneumocystis carinii?
Treat with TMP-SMX, pentamidine.
Pneumocystis carinii: 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: 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)
Sporothrix schenckii: What are the symptoms of Sporcitrichosis?
Local pustule or ulcer with nodules along draining lymphatics. Little systemic illness.
Sporothrix schenckii: How do you treat Sporcitrichosis?
Treat with itraconazole or potassium iodide.
Entamoeba histolytica: What disease(s) does it cause?
Amebiasis: bloody diarrhea, (dysentery), liver abscess, RUQ pain
Entamoeba histolytica: How is it transmitted?
Cysts in water
Entamoeba histolytica: How is it diagnosed?
Serology and/or trophozoites or cysts in stool
Entamoeba histolytica: How it is treated?
Metronidazole and iodoquinol
Giardia lamblia: What disease(s) does it cause?
Giardiasis: bloating, flatulence, foul-smelling diarrhea
Giardia lamblia: How is it transmitted?
Cysts in water
Giardia lamblia: How is it diagnosed?
Trophozoites or cysts in stool
Giardia lamblia: How it is treated?
Metronidazole
Cryptosporidium: What disease(s) does it cause?
Severe diarrhea in AIDS. Mild disease (watery diarrhea) in non-HIV
Cryptosporidium: How is it transmitted?
Cysts in water
Cryptosporidium: How is it diagnosed?
Cysts in water
Cryptosporidium: How it is treated?
Toxoplasma: What disease(s) does it cause?
Brain abscess in HIV, birth defects
Toxoplasma: How is it transmitted?
Cysts in meat or cat feces
Toxoplasma: How is it diagnosed?
Serology, biopsy
Toxoplasma: How it is treated?
Sulfadiazine + pyrimethamine
What are the different species?: What disease(s) does it cause?
Malaria: cyclic fever, headache, anemia, splenomegaly; Malaria - severe (cerebral)
What are the different species?: How is it transmitted?
Mosquito (Anopheles)
What are the different species?: How is it diagnosed?
Blood smear
What are the different species?: How it is treated?
Chloroquine (primaquine for P. vivax, P. ovale), sulfadoxine + pyrimethamine, mefloquine, quinine
Trichomonas vaginalis: What disease(s) does it cause?
Vaginitis: foul-smelling, greenish discharge; itching and burning
Trichomonas vaginalis: How is it transmitted?
Sexual
Trichomonas vaginalis: How is it diagnosed?
Trophozoites on wet mount
Trichomonas vaginalis: How it is treated?
Metronidazole
Trypanosoma cruzi: What disease(s) does it cause?
Chagas' disease (heart disease)
Trypanosoma cruzi: How is it transmitted?
Reduviid bug
Trypanosoma cruzi: How is it diagnosed?
Blood smear
Trypanosoma cruzi: How it is treated?
Nifurtimox
Trypanosoma gambiense & rhodesiense: What disease(s) does it cause?
African sleeping sickness
Trypanosoma gambiense & rhodesiense: How is it transmitted?
Tsetse fly
Trypanosoma gambiense & rhodesiense: How is it diagnosed?
Blood smear
Trypanosoma gambiense & rhodesiense: How it is treated?
Suramin for blood-borne disease or melarsoprol for CNS penetration
Leishmania donovani: What disease(s) does it cause?
Visceral leishmaniasis (kala-azar)
Leishmania donovani: How is it transmitted?
Sandfly
Leishmania donovani: How is it diagnosed?
Macrophages containing amastigotes
Leishmania donovani: How it is treated?
Sodium stibogluconate
Babesia: What disease(s) does it cause?
Babesiosis

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