Micro - Mycology (Opportunistic fungal infections & Others) Flashcards
Pg. 145-146 Sections include: Opportunistic fungal infections Pneumocystis jirovecii Sporothrix schenckii (34 cards)
What category(-ies) of infection does Candida albicans cause?
Systemic or superficial fungal infection
In what 6 ways can Candida albicans present, and where applicable, in what patient populations?
(1) Oral and esophageal thrush in immunocompromised (neonates, steroids, diabetes, AIDS) (2) Vulvovaginitis (diabetes, use of antibiotics) (3) Diaper rash (4) Endocarditis in IV drug users (5) Disseminated candidiasis (to any organ) (6) Chronic mucocutaneous candidiasis
How might Candida albicans infection present in immunocompromised patients? Give examples of immunocompromised patients.
Oral and esophageal thrush; Neonates, steroids, diabetes, AIDS
How might Candida albicans infection present in diabetic patients?
(1) Oral and esophageal thrush (since immunocompromised) (2) Vulvovagnitis
In what patient populations is Candida albicans likely to cause vulvovaginitis?
Diabetic, Users of antibiotics
What condition is Candida albicans likely to cause in drug users?
Endocarditis
How is Candida albicans infection treated in the following instances: (1) Vaginal (2) Oral/esophageal (3) Systemic?
(1) Topical azole (2) Fluconazole or Caspofungin (3) Fluconazole, Amphotericin B, or Caspofungin
What are the morphological characteristics of Candida albicans that may appear under microscope?
White (hence “alba”), Dimorphic yeast (may see pseudohyphae and budding yeasts [at 20 C] or germ tubes [at 37 C])
What are 3 ways that Aspergillus fumigatus may present, and in what patient populations and/or contexts?
(1) Invasive aspergillosis, especially in immunocompromised & those with chronic granulomatous disease (2) Allergic bronchopulmonary aspergillosis (ABPA): with asthma or CF (3) Aspergillomas in lung cavities, especially after TB infection
What kind of toxins do some species of Aspergillus fumigatus produce? With what kind of cancer are such toxins associated?
Aflatoxins; Hepatocellular carcinoma (HCC)
What are morphological characteristics of Aspergillus fumigatus that may be seen under microscope?
Not dimporphic, Septae hypae that branch at 45 degrees angle; Conidophore (specialized hyphal branch) with radiating chains of spores; Think: “ ‘A’ for Acute Angles in Aspergillus
What disease(s)/condition(s) does Crytococcus neoformans cause?
(1) Crytococcal meningitis (2) Crytococcosis
Where is Cryptococcus neoformans found in nature?
Found in soil, pigeon droppings
How is Cryptococcus neoformans acquired?
Acquired through inhalation with hematogenous dissemination to meninges
How is Crytococcus neoformans cultured? How is it stained?
Culture on Sabouraud’s agar; Stains with India ink and mucicarmine
What is the test used for Crytococcus neoformans? What does it detect? How does it compare to culture or stain?
Latex agglutination test detects polysaccharide capsular antigen; More specific
With what specific CNS finding is Crytococcus neoformans associated?
“Soap bubble” lesions in brain
What are morphological characteristics of Crytocococcal meningitis that may be seen under microscope?
Heavily encapsulated yeast. Not dimorphic. With capsular halos and unequal budding in India ink stain
What condition/disease do Mucor and Rhizopus fungi cause, and mostly in what patient populations?
Mucormycosis; Disease mostly in ketoacidotic diabetic and leukemic patients
What is the mechanism by which Mucor and Rhizopus proliferate and dissemiante after infection?
Fungi proliferate in blood vessels when there is excess ketone and glucose, penetrate cribiform plate, and enter brain
What CNS/ENT findings are associated with Mucor and Rhizopus infections?
Rhinocerebral, frontal lobe abscesses.
How do Mucor and Rhizopus infections present in history or on physical exam?
Headache, facial pain, black necrotic eschar on face, may have cranial nerve involvement
What are morphological characteristics of Mucor and Rhizopus that may be seen under microscope?
Irregular, broad, nonseptate hyphae branching at wide angles
What condition/disease can Pneumocystis jirovecii cause? What predisposes patients to this condition/disease?
Causes Pneumocystis pneumonia (PCP), a diffuse interstitial pneumonia; Immunosuppression (e.g., AIDS)
