Pneumocystis Flashcards
What characteristics of Pneumocystis resembles a protozoan?
- Cyst and troph stages
- Does not grow on artificial media in the lab
What characteristics of Pneumocystis resembles a fungus?
DNA sequencing
Is Pneumocystis jiroveci (formerly P. carinii) a fungus or a protozoan?
Fungus
What is the treatment for Pneumocystis infections?
Antibacterial agents (SXT) - NOT antifungal or antiparasitic agents
Which stain is more beneficial for recognizing cysts?
- GMS is more beneficial
- Giemsa, Kinyoun, or Gram stains are also used but more difficult to recognize
Which stain is more beneficial for recognizing trophs?
Giemsa stain
Describe the appearance of Pneumocystis trophs on Giemsa stains
Pale blue cytoplasm w/ small mass of reddish nuclear chromatin
Describe the appearance of Pneumocystis cysts on GMS and Giemsa, Kinyoun, or Gram stain
- May contain up to 8 intracystic bodies (“clock face”)
- Only cyst WALLS stain black w/ GMS (deflated beach balls; punched out pingpong ball)
- ONLY intracystic bodies of cysts stain w/ Giemsa, Kinyoun, or Gram stains
What is the best specimen to use for Pneumocystis jiroveci identification?
BAL specimen
Can Pneumocystis infections be found in healthy individuals?
Yes (asymptomatic)
- Abs are usually acquired early in life
Significance of a diagnosis w/ Pneumocystis w/ undiagnosed AIDS patients
Person who has Pneumocystis will be diagnosed w/ AIDS (often the first clue to new AIDS patients)
Patient populations that are at increased risk for infection w/ Pneumocystis
Healthy individuals (via respiratory transmission)
What is caused by Pneumocystis infections in immunosuppressed patients?
- Cause of pneumonia in immunosuppressed patients
- AIDS/HIV and post-transplant immunosuppression, leukemia patients on chemo
- Attaches/destroys alveoli
