Microbiology - Mycology & Parasites Flashcards
Systemic mycoses
- can cause pneumonia and can desseminate
- dimorphic fungi
- cold (20 C) = mold; heat (37C) = yeast
- Only exception is coccidioidmycosis, which is spherule (not yeast)
- can mimic TB (granuloma formation) except there is no person to person contact
Treatment for systemic mycoses
Fluconazole or Itraconazole for LOCAL infecton
Systemic mycoses (Name them) - Hint 4
Histoplasmosis
Blastomycosis
Coccidiomycosis
Paracoccidiomyocosis
Histoplasmosis
- found in MIssissippi and Ohio River Valleys
- Causes pneumonia
Macrophage filled with Histoplasma (smaller than RBC) - Found in bird or bat droppings
Blastomycosis
- found in states east of MS River or Central America
- Causes inflammatory lung disease and can disseminate to skin and bone
- Forms granulomatous nodules
- Broad-base budding (same size as RBC)
Coccidiomycosis
- found in Southwestern US, California
- Causes pneumonia and meningitis
- Can desseminate to bone and skin
- Case rate increases after earthquakes (spores in dust are thrown up in aire and becomes spherules in lungs)
- Spherules flled with endospores (much larger than RBC)
Paracoccidiomycosis
Latin America
Budding yeat with “captain’s wheel” formation (much larger than RBC)
Tinea versicolor
- caused by Malassezia furfur
- degradation of lipids that causes acids that damages melanocytes and cause hypopigmented and/or hyperpigmented patches
- Occurs in hot, humid weather
Treatment for tinea versicolor
Topical miconazole, selenium sulfide (Selsun
“Spaghetti and meatball” appearance on KOH prep
Tinea versicolor
Other tinae
Tinea pedis (foot) Tinea cruris (groin) Tinea corporis (ringworm on body) Tinea capitis (head, scalp) Tinea unguium (Onychomycosis, on fingernails)
Appearance of tinea
Pruritic lesions with central clearning resembling ring, caused by dermatophytes (Microsporum, Trichophyton, Epidermophyton)
- See mold hyphae on KOH
Candida albicans
- opportunistic fungal infections
- systemic or superficial infection
- oral or esophageal thrush in immunocompromised pts (AIDS, diabetes, steroids, neonates)
- vulvovaginitis (diabetic patents)
- endocarditis in IV drug users
Treatment of Candida albicans
- Topical azole for vulvovaginitis
- fluconazole or caspofungin for oral/esophageal thrush
- Fluconazole, amphotericine B or caspofungin for systemic disease
Aspergillus fumigatus
Invasive aspergillosis, especially in immunocompromised and those with chronic granulomatous disease
- Aspergillomas found in lung cavities, especially after TB infection
- Acute Angles in Aspergillus
Aspergillus fumiagtus infection with asthma or CF
Allergic bronchopulmonary aspergilosis (APBA)
Discuss Aspergillus and Hepatocellular carcinoma
- some Aspergillus species produce ANAFLATOXINS associated with HCC
Cryptococcus neoformans
Opportunistic fungal infection
Cryptococcal meningitis, Cryptococcosis
Heavily encapsulated yeast. Not dimorphic.
- Acquired through inhalation with hematogenous dissemination to meninges
- “Soap bubble” lesions in brain
Diagnosis for Cryptoccocus neoformans
- “Soap bubble” lesions in (HIV patienty?)
- Culture on Sabouraud’s agar
- Stains with India ink
- Latex agglutination test detects polysaccharide capsular antigen (is more specific)
Mucor and Rhizopus spp.
Mucormycosis
- Disease mostly in ketoacidotic diabetic and leukemic patients
- Fungi proliferate when there is excess ketone and glucose, penetrate cribiform plate, and enter brain
- Rhinocerebral, frontal lobe abcesse
Sx: Occurs in ketoacidotic diabetic and leukemic patients
Headache, facial pain, black necrotic eschar on face, may have cranial nerve involvement
Mucor and Rhizopus spp.
Pneumocystis jirovecci
Causes PCP, a diffuse interstitial pneumonia
- Inhaled. Most infections are assymptomatic
- Immunosuppression (e.g. AIDS) predisposes to disease.
Diagnosis of Pneuocystis jirovecci
- Diagnosed by lung biopsy or lavage
- Disc shaped yeat forms on methenamine silver stain of lung tissue
- Diffuse, bilateral CXR
Tx of pneumocystis jirovecci
TMP-SMX, pentamidine, dapsone
- Start prophylaxis when CD4 drops < 200 cells/mm
Sporothrix schenckii
Sporotrichosis
Dimorphic, cigar shaped budding yeast that lies on vegetation
- “Rose Gardner’s disease” - when spores are traumatically introduced by skin (e.g. thorn)
- Causes local pustule or ulcer with nodules along draining lymphatics (ascending lymphaginitis)
- Little systemic illness
Treatment of sprothrix schenckii
Itracanazole or Potasium iodid
Opportunistic Fungal Infections
- Candida albicans
- Aspergillus fumagitus
- Cryptococcus neoformans
- Pneumocystis jirovecci
- Sporothrix schenckii
- Mucor and Rhizopus spp
GI infection protozoas
Giardia lamblia
Entamoeba histolytica
Cryptosporidium
Giardia lamblia
Giardiasis: bloating, flatulence, foul-smelling, fatty diarrhea (often seen in campers/hikers) -
Giardia lamblia transmission
Cysts in water
Diagnosis of Giardia lamblia
Trophozoites or cysts in stool
Treatment of Giardia Lamblia
Metronidazole
Entamoeba histolytica
Amebiasis: bloody diarrhea (dysentery), liver abscess (“anchovy paste” exudate
- RUQ pain
- Histology: flash-shaped ulcer is submucosal ulcer in colon ruptures
Transmission of Entamoeba histolytica
Cysts in water
Treatment of Entamoeba histolytica
Metronidazole
Iodoquinol for assymptomatic cyst passers
Diagnosis of Entamoeba histolytica
Serology and/or
Trophozoites (with RBCs in the cytoplasm)
Cysts (with multiple nuclei) in stool
Cryptosporidium
Severe diarrhea in AIDS Mild disease (watery diarrhea in healthy individuals)
Transmission of cryptosporidium
Cysts in water
Diagnosis of Cryptosporidium
Cysts in acid-fast stain
Treatment of Cryptosporidium
Prevention ( by filtering city water supplies)
Nitazoxamide in immunocompotent host
Protoza-CNS infections
Toxoplasma gondaii Naegleria fowleri Trypanosomas brucei T. gambiense T. rhodesiense
Toxoplasma gondii
Brain abscess in HIV (seen in ring-ENHANCING lesions on CT/MRI)
Triad of Congenital Toxoplasmosis
Chorioretinitis
Hydrocephalys
Intracranial calcifications
Transmission of toxoplasma gondii
Cysts in meat or cat feces; Crosses placenta (pregnant women should avoid cats)
Diagnosis of Toxoplasma Gondii
Serology
Biopsy
“Crescent shaped trophozoite within macrophages)
Treatment of Toxoplasma Gondii
Sulfadiazine + Pyremethamine
Naegleria fowleri
Rapidly fatal meningoencephalitis
- transmitted by swimming FRESHWATER lakes, enters via cribiform plate
- diagnosed by amoebas in spinal cord
Tx: amphotericin (for the few survivors)
Trypanosoma brucei
African sleeping sickness
- enlarged lymph nodes, recurring fever (due to antigenic variation)
- Somnolence, Coma
- transmitted by Tsetse fly, a painful bite
- diagnosed by blood smear
Treatment of Trypanosoma brucei (African sleeping sickness)
Suramin for blood borne disease
Melarsoprol for CNS penetration
Melatonin helps with sleep
Protozoa for Hematologic infections
Plasmodium
Babesia
Plasmodium
P. vivax/ovale
P. falciparum
P. malariae
Malaria: fever, headache, anemia, splenomegaly - seen in Africa, India
- transmitted by Mosquito (Anopheles)
P. vivax/ovale
malaria
- 48 hour cycle (tertian; includes fever on 1st day thus fevers are 48 hours apart)
- Dormant form (hypnozite) in liver - infects NEW RBCs
P. faciparum
sever; irregular fever patters
parasitized RBCS - infects ALL RBCs
- occlude capillaries in brain (cerebral malaria), kidneys, lungs
P. malariae
72 hours cycle
Malaria Diagnosed
Blood smear
Trophozoite ring form
RBC schizpont with merozoites
Treatment of malaria
Chlorquine - blocks Plasmodium heme polymerase
- Mefloquine
- Life threatening: quinidine (but test for G6PD deficiency
- Vivax/ovale - add primaquine if hypnozoite (test for G6PD deficiency)
Trypanosoma cruzi
Chagas disease:
- dilated cardiomyopathy
- mega colon, megaesophagus
- predominantly in South America
- transmitted by Reduviid bug (“kissing bug”)
- diagnosed by blood smear
- treated with Nirfurtimox
Leischemasia donovani
Visceral leischmaniasis
(kala-azar)- hyperpigmented skin pattches
Sx: Spiking fevers, Hepatosplenomegaly
Pancytopenia
- transmitted by sandfly
- diagnosed with macrophages containing amastigotes)
- treated with Sodium stibogluconate
Trichomonas vaginalis
Vaginitis: foul-smelling, GREENISH discharge; itching and burning
- transmitted by sex (can’t exist outside of human)
- diagnosed by trophozoites (MOTILE) on wet mount
- treatmetn: metronidazole for patient and partner
** Not be confused with Gardnerella vaginella (bacterium)
Enterobious vemicularis (pinworm)
- nematodes (roundworm)
- get by ingesting food contaminated with eggs
- intestinal infection causing anal pruritis (diagnosed via Scotch tape tes)
- treated with benzadoles or pyrantel pamoate
Ascaris lumbricoides (giant roundworm)
- nematodes (roundworm)
- transmitted fecal-orally; eggs visible in feces in microscope
- intestinal infection
- treated with benzadoles or pyrantel pamoate
Strongyloides stercolaris
- nematodes (roundworm)
- larvae in soil penetrate the skin
- intestinal infection causing VOMITING, DIARRHEA, ANEMIA
- treatment: ivermectin or albendazole
Acylostoma duodenale, Nectar americanicus
Hook worms
- nematodes (roundworms)
- larvae penetrate skin
- intestinal infection causing anemia by sucking blood from intestinal walls
- treatment: bendazoles or pyrantel pamoate
Dracunulus medinesis (Guinea worm)
- nematodes (roundworms)
- found in drinking water
- causes skin inflammation and ulceration
- treatment: slow extraction of worm
Onchocera volvuls
- nematodes (roundworm)
- transmitted by female blackfly bite
- causes hyperpigmented skin and river blindness
- possible allergic reaction to microfilaria
- treatment: ivermectin
Loa Loa
- nematodes
- roundworm
- transmitted by deerfly, horsefly, mangofly
- causes swelling in skin, worm in conjunctiva
- treatment: diethylcarmabazine
Wuchereria bancrofti
- nematodes
- block lymphatic vessels
- elephantiasis: takes 9 months - 1 year after bite to become symptomatic
- treatment: diethylcarbamazine
Toxocara canis
- nematodes
- transmitted by food containing eggs
- causes visceral larva migrans (moving larvae)
- treatment albendazole or mebendazole
Nematodes routes of infection
Ingested (“EAT”) - Enterobius, Ascaris, Toxocara
Cutaneous (“SANd”) - Strongyloides, Ancylostoma, Necator
Taenia solium
- tapeworm
- ingestion of larvae in undercooked pork
- ingestion of eggs
- can cause intestinal infection and cystercosis (infect skeletal muscle),
neurocysticosis - treatment: praziquantel (and - bendazole for neurocysticercosis)
Diphyllobothrium latum
- tapework
- tapeworm (cestodes)
- ingesting of larvae from raw fish
- can cause Vitamin B12 deficiency (tapeworm competes for Vitamin B12) –> anemia
- treatment: praziquantel
Echinococcus granulosus
- tapeworm
- cestodes (tapeworm)
- ingestion from eggs from dog feces
- cysts in liver, causing anaphylaxis if antigens release (surgeons inject ethanol to kill cysts)
- treatment: - bendazoles
Shistosoma
- trematodes (flukes)
- transmitted by snailes; cercarie penetrate human skin
- cause liver and spleen granulomas and inflammation
- chronic infection with S. haematobium can lead to SCC of bladder
- treatment: praziquantel
Clonorchis sinensis
- trematodes (flukes)
- found in undercooked fish
- can cause biliary tract inflammation –> pigmented gallstones
- associated with cholangiocarcinoma
- treatment: praziquantel
Paragonimus westermani
- trematodes
- found in undercooked crab meat
- can cause lung inflammation and secondary bacterial infection, with hemoptysis
- treatment: praziquantel
Parasite : Brain cysts, seizures
Taenia solium (cysticercosis)
Parasite: liver cysts
Echinococcus granulosus
Parasite: Vitamin B 12 deficiency
D. latum
Parasite: Biliary tract disease, cholangiosarcoma
Clonorchis sinesis
Parasite: Hemoptysis
Paragonimus westermani
Parasite: Portal hypertension
Schistosoma mansoni
Parasite: Hematuria, bladder cancer
Schistosoma haematobium
Parasite: microcytic anemia
Ancylostoma, Necator
Paraisite: perianal pruritis
Enterobius
