MIDTERM LEC 2: PNEUMOCYSTIS SPP. Flashcards
New/current name of Pneumocystis carnii
Pneumocystis jirovecii
Primary host of P. wakefieldiae/P. carinii
rats (rodents)
Primary host of P. jirovecii
humans
P. carinii was originally classified with what protozoa?
trypanosome
How was P. carinii reclassified from protozoa to fungi?
Through nucleic acid
sequencing (showed it is a fungus)
Pneumocystis spp. most often recovered from humans
P. jirovecii
T/F: P. jirovecii is an opportunistic, atypical fungus that
infects immunocompromised hosts
true
P. jirovecii mostly manifests as what disease?
Pneumocystic Pneumonia (PCP) / Pneumocystis jirovecii pneumonia (PJP)
At what age do most children gain antibodies against pneumocystic pneumonia?
2-4 years old
Pneumocystis infection is (asymptomatic/symptomatic?) in immunocompetent patients
asymptomatic
Hallmark of PJP/PCP
interstitial pneumonitis
The hallmark of PJP, interstitial pneumonitis, is accompanied with
a mononuclear infiltrate composed predominantly of plasma cells
Pneumocystis spp. is initially identified as the
causative agent of?
interstitial plasma cell pneumonia
In which patients is interstitial plasma cell pneumonia commonly seen?
malnourished or premature infants
Which specialized cells does interstitial plasma cell pneumonia target?
type I pneumocytes (for gas exchange)
Pneumocystis remained one of the
primary opportunistic infections found in
patients with what type of disease?
AIDS
Since what year has Pneumocystis been the primary opportunistic infection of patients with AIDS?
since the early 1980s
What are the symptoms of PJP/PCP?
- nonproductive cough (cough with no mucus)
- difficulty breathing
- low-grade fever
Range of temperature of low-grade fever
37.5°C - 38.3°C
What findings might a chest radiograph of a patient with PJP show?
normal or a diffuse interstitial infiltrate
What causes normal or diffuse interstitial infiltrate findings on a chest radiograph?
Due to the organism’s immunological response after
it binds to and destroys alveolar cells.
Environmental sources or reservoirs of Pneumocystis jirovecii
- soil
- water
- airborne particles
- animal reserviors
Mode of transmission of P. jirovecii
Inhalation of airborne particles
Invasive stage of P. jirovecii
trophic form
Infective stage of P. jirovecii
mature cyst
State the developmental stages of Pneumocystis jirovecii from the invasive stage to the infective stage.
trophozoite (trophic form) - precyst - cyst
How do trophic forms ASEXUALLY multiply on the surface of the epithelial cells (pneumocytes) lining the lungs?
through binary fission
By producing what, do trophic forms SEXUALLY multiply?
producing precyst and then cyst containing spores/intracystic bodies
What procedure is used to find cysts and trophozoites in tissue for the laboratory diagnosis of PJP?
open lung biopsy
T/F: Pneumocystis spp. can be cultured outside the lungs
false
(it cannot be cultured outside the lungs, thus open lung biopsy is needed for diagnosis)
Clinical standard specimen for the laboratory diagnosis of PJP
bronchoalveolar lavage (BAL) fluid
Least productive specimen
sputum
Lavage and sputum specimens are often prepared using what machine
cytocentrifuge
Why is cytocentrifuge needed for preparing lavage and sputum specimens?
to decrease bacterial contamination
Othe specimens for the laboratory diagnosis of PJP
- transbronchial biopsy
- tracheal aspirate
- pleural fluid
- induced sputum
What stain is utilized if cyst wall of Pneumocystis spp. is BARELY VISIBLE
giemsa stain
In giemsa stain, what is the color of nuclei?
pink
Identify the stain used:
Intracystic bodies are seen around the
interior of the organism
giemsa stain
Identify the stain:
Cyst wall stains black
gomori methenamine silver stain
What stain detects chitin in the cell wall?
calcoflour white
What stain demonstrates punched-out pingpong ball appearance of cyst?
gomori methenamine silver stain
Commercially available and widely used stain for Pneumocystis spp.
immunofluorescent monoclonal antibody stain
What stain fluoresce with a blue-white color?
calcofluor white
Treatment of choice for PJP/PCP
Trimethoprim-sulfamethoxazole
(TMP-SMX)
Trimethoprim-sulfamethoxazole
is also known as?
co-trimoxazole
How is TMP-SMX administered to patients?
through a vein or by mouth for 3
weeks
Possible side effects after taking TMP-SMX
rash and fever
For first line treatment, dapsone is combined with?
pyrimethamine
First line of treatment
- Pentamidine isethionate
- Dapsone (combined with pyrimethamine)
- Aerosolized pentamidine
For what purpose do patients with AIDS use aerosolized pentamidine?
for prophylactic treatment
