Microbiology: Mycoses, Parasites Flashcards Preview

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Flashcards in Microbiology: Mycoses, Parasites Deck (47):
1

Systemic Mycoses

  • Cause pneumonia
    • Histoplamosis
    • Blastomycosis
    • Coccioidomycosis
    • Paracoccidioidomycosis
  • dimorphic fungi
    • cold (20C)= mold
    • heat (37)= yeast (except cocci= sperule)
  • Tx:
    • fluconazole or itraconazole for local infection
    • amphotericin B for systemic infection

2

Histoplasmosis

  • Dimorphic fungi ( cold= fungi, heat= yeast)
  • Mississippi and Ohio river valley
  • pneunomia
  • bird or bat droppings

*Histo hides*

3

Blastomycosis

  • dimorphic fungi (cold= mold, heat= yeast)
  • States east of Mississippi River and Central America
  • Causes inflammatory lung disease
  • can disseminate to skin and bones
  • Forms granulomatous nodules
  • Broad base budding

*Blasto buds Broadly*

4

Coccidioidomycosis

  • dimorphic fungi ( cold = mold, heat=spherule)
  • Southwestern US, Calfornia
  • Causes pneumonia and meningitis
  • can disseminated to bone and skin
  • increase rate after earthquakes
  • spherules are filled with endospores
  • San Joaquin Valley Fever
  • Desert bumps= erythema nodosum
  • Desert rheumatism= arthralgias

*Coccidio Crowds*

5

Paracoccidioidomycosis

  • dimorphic fungi (cold= mold, heat= yeast)
  • Latin American
  • Budding yeast with 'captain's wheel' formation

*Paracoccidio parasails with the captain's wheel all the way to Latin America"

6

Malassezia furfur

  • Cutaneous mycoses
  • Tinear Versicolor
  • degradation of lipids produce acids that damage malanocytes and cause hypopigmentation and/or hyperpigmented patches
  • "spaghetti and meatball" appearance
  • occurs in hot, humid weather
  • Tx: topical miconazole, selenium sulfide

7

Dermatophytes:

Microsporum

Trichophyton

Epidermophyton

  • Pruritic lesions with central clearing resembling a ring
  • see mold hyphae in KOH prep
  • Includes
    • tinea pedis (foot)
    • tinea cruris (groin)
    • tinea corporis (ringworm on body)
    • tinea capitis (head, scalp)
    • tinea unguinum (onychomycosis on fingernails)

8

Candidia albicans

  • opportunistic fungal infection
  • systemic or superficial fungal infection

Causes

  • oral and esophageal thrush in immunocompromised (neonates, steroids, AIDS, diabetes),
  • vulvovaginitis (diabetes, abx),
  • diaper rash
  • endocarditis in IVDU
  • disseminanted candidiasis
  • chronic mucocutaneous candidiasis

Treatment

  • topical azole for vaginal
  • fluconazole or caspofungin for oral/esophageal
  • fluconazole, amphotericin B or caspofungin for systemic

9

Aspergillus fumigatus

  • opportunistic fungal infection
  • invasive aspergillosis ( immunocompormised and chronic granulomatous disease)
  • Allergic bronchopulmonary aspergillosis (ABPA): associated with asthma and cystic fibrosis
    • may cuase bronchietasis and eosinphilia
  • Aspergillomas in lung cavities, esp after TB infection
  • some species of Aspergillus produce aflotoxins ( associated with HCC)

*Acute Angles in Aspergillus. Not dimorphic*

(Hyphae at 45* angle)

10

Cryptococcus neoformans

  • Opportunistic fungal infection
  • Cryptococcal meningitis, cryptococcosis
  • Heavily encapsulated yeast
  • Not dimorphic
  • found in soil, pigeon droppings
  • acquired through inhalation with hematogenous dissemination to meninges
  • Culture on Sabouraud agar
  • Stains with India Ink and mucicarmine
  • Latex agglutination test detects polysaccharide capsular antigen
  • "soap bubble" lesions in brain

11

Mucor and Rhizopus

  • Opportunistic fungal infection
  • Mucormycosis
  • Disease mostly in ketoacidotic diabeteic and leukemia patients
  • Fungi proliferate in blood veessle walls when there is excess ketones and glucose, penetrate cribiform plate and enter brain
  • Rhinocerebral, frontal lobe abscesses
  • Headache, facial pain, black necrotic eschar on face
  • Tx: amphotericin B

12

Pneumocystitis pneumonia (PCP)

  • opportunistic fungal infection
  • diffuse interstial pnumonia
  • Yeast
  • Inhaled
  • Diffue, b/l CXR appearance
  • Diagnosed by lung biopsy or lavage
  • Disc-shaped yeast forms on methenamine silver stain of lung tissue
  • Tx: TMP/SMX, pentamidine
  • Prophylaxis: dapsone, atorvaquone
    • start when CD4 drops <200 in HIV pts

13

Sporothrix schenckii

  • Opportunistic fungal infection
  • Sporotrichosis
  • Dimorphic, cigar shaped budding yeast that lives on vegetation
  • when spores are traumatically introduced into skin, (thorn, "rose gardener's disease") causes a local pustule or ulcer with nodules along draining lymphatics (ascending lymphangitis)
  • little systemic illness
  • Tx: itraconazole or potassium iodide

* Plant a rose in a pot*

14

Giardia lamblia

  • Protozoa: GI infection
  • Giardiasis
    • bloating, ftalulence, foul smelling, fatty diarrhea
  • often seen in campers and hikers
  • Transmission: cysts in water
  • Dx: Trophozoites or cysts in stool
  • Tx: metronidazole

* Fat rich Ghiaradelli chocolates for fatty stools of Giardia*

15

Entamoeba histolytica

  • Protozoa: GI
  • Amebiasis:
    • bloody diarrhea (dysentary)
    • liver abscess (anchovy paste exudate)
    • RUQ pain
  • Histology: flask shaped ulcer if submucosal abscess of colon ruptures
  • Transmission: cysts in water
  • Dx:
    • serology
    • trophozoites (RBC in cytoplasm) 
    • cysts in stool
  • Tx:
    • metronidazole
    • Iodoquinol for asymptomatic cyst passes

16

Cryptosporidium

  • Protozoa: GI
  • Severe diarrhea in AIDS
  • mild disease (watery diarrhea) in immunocompromised
  • Transmission: Oocytes in water
  • Dx: Oocytes on acid-fast stain
  • Tx: 
    • prevention: water filtration
    • Nitazoxanide: immunocompetent hosts

17

Toxoplasma gondii

  • Protozoa: CNS
  • Brain abscess in HIV (ring enhancing lesions on CT)
  • congenital toxoplasmosis
    • chorioretinitis
    • hydrocephalus
    • intracranial calcification
  • Transmission:
    • Cysts in meat
    • oocytes in cat feces
  • Crosses placenta! ( pregnant women avoid cats)
  • Dx: Serology, biopsy (tachyzoite)
  • Tx: Sulfadiazine & pyrimethamine

18

Naegleria fowleri

  • Protozoa: CNS
  • Rapidly fata meningoencephalitis
  • Transmission: swimming in freshwater lakes
    • enters cribiform plate
  • dx: amoebas in spinal fluid
  • Tx: Amphotericin B

*Nalgene bottle filled with fresh water containing Naegleria)*

19

Trypanosoma brucei

  • Protozoa: CNS
  • African sleeping sickness
    • enlarged lymph nodes
    • recurring fever ( antigenic variation)
    • somnolence, coma
  • Species
    • rhodesiense
    • gambiense
  • Transmission: Tsetse fly, painful bite
  • Dx: blood smear
  • Tx: 
    • suramine: blood bourne disease
    • melarsoprol: CNS penetration

* It sure is nice to go to sleep. Melatonin helps with sleep*

20

Plasmodium

  • P. vivax/ ovale
  • P. falciparum
  • P. malariae

  • Protozoa: Hematologic
  • Malaria: fever, headache, anemia, splenomegaly
  • Transmission: Mosquito (anopheles)
  • Dx: blood smear, trophozoite ring from in RBC, schizont containing merozoites
  • P. vivax/ovale
    • 48 hr cycle
    • includes fever on first day and third day
    • dormant form in liver (hypnozoite)
  • P. falciparum
    • severe, irregular fever pattern
    • parasitized RBCs occlude capillaries in brain, kidneys, lung
  • P. malariae
    • 72 hr cycle (quartan)
  • Tx
    • Chloroquine: blocks plasmodium heme polymerase (mefloquine, atovaquone/proguanil)
    • life treatening: IV quinidine ( test for G6PD deficiency)
    • vivax/ovale: add primaquine for hypnozoite (test for G6PD deficiency)

21

Babesia

  • Protozoa: Hematologic
  • Babesiosis: fever, hemolytic anemia
  • predominantly in northeast US
  • asplenia increases risk for disease
  • Transmission: Ixodes tick ( same as Borrelia- Lyme dz)
  • Dx:
    • blood smear: ring form, maltese cross
    • PCR
  • Tx: atovaquone & azithromycin

22

Trypanosoma Cruzi

  • Protozoa
  • Chagas disease
    • dilated cardiomyopathy
    • megacolon
    • megaesophagus
    • predominantly in South America
  • Transmission: Reduviid bug (kissing bug) feces, deposited in a painless bite
  • Dx: blood smeal
  • Tx: Benznidazole or nifurtimox

23

Leishmania donovani

  • Protozoa
  • Visceral leishmaniasis
    • spiking fevers
    • hepatosplenomegaly
    • pancytopenia
  • Transmission: Sandfly
  • Dx: macrophages containing amastigotes
  • Tx: amphotericin B, sodium stibogluconate

24

Trichomonas vaginalis

  • Protozoa
  • Vaginitis
    • foul smelling, greenish discharge
    • itching and burning
  • Sexual transmission
  • Dx:
    • Trophozoites (motile) on wet mount
    • strawberry cervix
  • Tx: metronidazole for pt and partner (prophylaxis)

NOT Gardnerella vaginalis (bacterial vaginosis)

25

Enterobius vermicularis

  • Nematode (pinworm)
  • Tranmission: fecal oral
  • Intestinal infection causing anal pruritus
  • Dx: scotch tape test
  • Tx: Bendazole or pyrantel pamoate

* worms are bendy*

26

Ascaris lumbricoides

  • Nematode (giant roundworm)
  • Transmission: fecal-oral (eggs visible in feces under microscope)
  • Intestinal infetion
  • Tx: bendazole or pyrantel pamoate

27

Strongyloides stercoralis

  • Nematode
  • Transmission: larvae in soil penetrate the skin
  • Disease: intestinal infection causing vomiting, diarrhea, epigastric pain (may be peptic ulcer like)
  • Tx: Ivermectin or albendazole

28

Ancylostoma duodenale

Necator americanus

  • Nematode (hookworms)
  • Transmission: larvae penetrate skin
  • Intestinal infection causing anemia by sucking blood from intestinal wall
  • Tx: Bendazole or pyrantel pamoate

29

Onchocerca Volvulus

  • Nematode
  • Transmission: female blackfly bite
  • Hyperpigmented skin and river blindness
  • allergic reaction to microfilaria possible
  • Tx: Ivermectin

* Black flies, black skin nodules, black sight*

*Ivermectin for river blindness*

30

Loa Loa

  • Nematode
  • Transmission: deer fly, horse fly, mango fly
  • Swelling skin, worm in conjunctiva
  • Tx: Diethylcarbamazine

31

Wuchereria bancrofti

  • Nematode (roundworm)
  • Transmission: Female mosquito
  • Blocks lymphatic vessels, elephantitiasis
  • takes 9 mo to 1 year after bite to become symptomatic
  • Tx: Albendazole or mebendazole

32

Toxocara canis

  • Nematode
  • Transmission: fecal oral
  • visceral larval migrans
  • Tx: albendazole or mebendazole

33

34

Nematodes Routes of infection:

Ingested

Cutaneous

Bites

  • Ingested: Enterobius, Ascaris, Toxocara
    •  you'll get sick if you EAT these!

 

  • Cutaneous: Strongyloides, Ancylostoma, Necator
    • These get in your feet in the SANd

 

  • Bites: Loa loa, Onchocerca, Wuchereria bancrofti
    • lay LOW to avoid getting bitten

35

Taenia solium

  • Cestode
  • Transmission: ingestion of larvae encysted in undercooked pork or Ingestion of eggs
  • Intestinal infection
  • Cysticercosis, neurocysticercosis
  • Tx: Praziqunatel (albendazole for neurocysticercosis)

36

Diphyllobothrium latum

  • Cestode
  • Transmission: Ingestion of larvae from raw freshwater fish
  • Vitamin B12 deficiency leads to anemia
  • Tx: Praziquantel

37

Echinococcus granulosus

  • Cestode
  • Transmission: Ingestion of eggs from dog feces
  • Hydatid cysts in liver, causing anaphylaxis if antigens released
  • Tx: Albendazole

38

Schistosoma

  • Trematode
  • Transmission: Snails are host
    • cercariae penetrate skin of humans
  • Liver and spleen granulomas, fibrosis and inflammation
  • Chronic infection with S. haematobium can lead to squamous cell carcinoma of the bladder ( painless hematuria)
  • Tx: Praziquantel

39

Clonorchis sinensis

  • Trematode
  • Transmission: undercooked fish
  • biliary tract inflammation leading to pigmented gallstones
  • associated with cholangiocarcinoma
  • Tx: Praziquantel

40

Parasite association:

Biliary tract disease

cholangiocarcinoma

Clonorchis sinensis

 

41

Parasite association:

Brain cysts

seizures

Taenia solium

 

42

Parasite association:

Liver (hydatid) cysts 

Echinococcus granulosus

43

Parasite association:

Microcytic anemia

Ancylostoma, Necator

 

44

Parasite association:

perianal pruritis

Enterobius

 

45

Parasite association:

Portal HTN

Schistosoma mansonii

Schistosoma japonicum

46

Parasite association:

Vitamin B12 deficiency

Diphyllobothrium latum

47