Blastocystis spp (B. hominis)

  • Blastocystis hominis is comprised of a number of different subtypes with varying degrees of pathogenicity.

  • Treatment recommended if symptomatic and other causes (infectious/non-infectious) of diarrhea have been excluded.

  • Little data available on optimal therapy.

Symptoms

  • diarrhea
  • abdominal pain and cramping
  • nausea

Asymptomatic

Drug Dose Duration
None    

Symptomatic

Drug Dose Duration
Metronidazole Adult: 750mg PO tid 10 days
  Paediatric: 35-50mg/kg/d PO div tid 10 days
or    
TMP/SMX Adult: 1 DS tab PO bid 7 days
  Paediatric: 6mg/kg/d TMP PO div bid 7 days
or    
Nitazoxanide Adult: 500mg PO bid 3 days
  Paediatric: 1-3 yo - 100mg PO bid 3 days
  Paediatric: 4-11 yo - 200mg PO bid 3 days

yo = years old