free-living pathogenic amebae Flashcards
epidemiology
infections occured as epidemic in subtropical countries
B. hominis
[TROPH]
- SIZE: 12-45 um
- MOTILITY: sluggish, spinelike pseudopods
- NUCLEI: one
- KARYOSOME: large
- PERIPHERAL CHROMATIN: absent
- CYTOPLASM: granular and vacuolated
Acanthamoeba
diagnosis
microscopic examination:
- CSF is the specimen of choice
- brain tissue
- corneal scrapings
Acanthamoeba
treatment
- intravenous/spine
- Amphotericin B - DOC
- Amphotericin B with rifamfin / miconazole
N. fowleri
Blastocystis hominis
- most predominant
- large central vacuole (reproductive organelle) and very thick capsule
vacuolated forms
treatment for B. coli
- metronidazole
- tetracycline
- iodoquinol
[TROPH]
- SIZE: 28-152 um (length) & 22-123 um (width)
- MOTILITY: rotary, boring
- NUCLEI: two, kidney shaped (macronucleus) and small spherical (micronucleus)
- 1 or 2 vacuoles
- CYTOPLASM: may contain food vacuoles or bacteria
- small cytostome present
- layer of cilia around the organism
Balantidium coli
Blastocystis hominis
- active extensions and pseudopodia
- nuclear chromatin: peripheral clumping
- intermediate stage between vacuolar and pre-cystic
ameba-like forms
[CYST]
- SIZE: 5-22 um
- SHAPE: ovoid, ellipsoid, triangular
- NUCLEI: one
- KARYOSOME: large, eccentric achromatic granules may be present
- PERIPHERAL CHROMATIN: absent
- CYTOPLASM: coarsely granular and vacuolated
- INCLUSIONS: well-defined glycogen mass may be present
N. fowleri
epidemiology
- found in warm bodies of water, lakes, streams, ponds, and swimming pools
- can survive in 0.5ug/mL of hyperchlorinated water
- high cases in summer
- can survive in elevated temperatures (46 degrees C)
- can be acquired in contaminated dust
N. fowleri
diagnosis
molecular techniques for N. fowleri
ELISA
PCR
diagnosis
culture for Acanthamoeba
- proteose-peptone
- yeast extract
- PYGC
epidemiology
- causes CNS and eye infection
- CNS infection in immunocompromised patients
- isolated from air, aquaria, bottled mineral water, soil swimming pools, deep well water, contact lens solutions
Acanthamoeba
Blastocystis form
- very prominent and thick osmophilic electron dense wall
- thick walled cyst: responsible for external transmission
- thin walled cyst: reinfection within a hosts intestinal tract
cystic form
[TROPH]
- SIZE: 8-22 um
- MOTILITY: sluglike, blunt pseudopods
- NUCLEI: one
- KARYOSOME: large (center)
- PERIPHERAL CHROMATIN: absent
- CYTOPLASM: granular, vacuolated
N. fowleri