Systemic and Opportunistic Mycoses

Question 1

Fungal Opportunistic Pathogens

Answer 1

Opportunistic pathogens:

• Unable to cause overt disease in healthy host
• Need an opportunity to become pathogenic
• Defects in immune function
• Defects in barrier function

Pathogenic Opportunistic Fungi
Candida
Cryptococcus
Aspergillus
Mucor and Rhizopus
Pneumocystis

Question 2

Candida

Answer 2

*Infection/disease
Mucocutaneous candidiasis
Disseminated candidiasis
*Morphology
Yeast thar reproduce by budding
form threadlike hyphae and sausage-like pseudohyphae
Colonies are discrete, circular, smooth, and white
*Epidemiology
C. albicans (all humans get it within a month)
Antibiotics, HIV

Question 3

Candida Clinical syndromes

Answer 3

*Mucocutaneus: thrush (mouth), esophagus, diaper rash, vulvovaginal, low mortality but high morbidity
Antibiotics, barrier disruption, diabetes, T cell dysfunction (babies, HIV, IL17 path deficit, meds-steroids, chemo)

Disseminated: organs (liver, meninges, renal) mortality can be 40%
Antibiotics, IV, GI surgery, hemodialysis, extremes of age, severe neutropenia

Lab tests: KOH prep, silverstain, gram stain, culture, serum

Treatment: Oral-nystatic, clotrimazole troche, gentian violet
skin-nystatin, miconazole, ketoconazole
disseminated- systemic anti fungal therapy, echinocandins, azoles, amphotercin

Question 4

Cryptococcus infections

Answer 4

Infection: cryptococcosis
Morphology: uninucleate budding yeast, round to oval, india ink
Epidemiology: soil, bird poop, inhaling cells
Species: C. neoformans: HIV and steroid use, C. gatti: immunocompetent hosts

Clinical Syndromes: Initial pulmonary infections (asymptomatic/mild), dissemination to organs via blood/lymphatics (cerebromeningitis) fever, headache, brain stuff

Lab diagnostics: Blood/CSF for india ink stain with a capsule
Treatment: amphotericin B and flucystosine and oral azole

Question 5

Aspergillus

Answer 5

Infection: aspergillosis
Morphology: mold
Epidemiology: saprophyte, found in soil, spores widespread and inhaled
Clinical syndromes: invasive disease (immunocompromised, respiratory tract, angiovasive disease)
Lab: KOH, IGE
Treatment: Voriconazole, amphotericin, resection

Question 6

Mucormycosis

Answer 6

Morphology: mold
Epidemiology: Rare, soil, inhalation, immunocompromised, burns, diabetes
Clinical symptoms: Rhino cerebral, pulmonary, cutaneos,
Lab diagnostics: tissue histology
Treatment: debriment (amphotericine B, posaconazole NOT VORICONAZOLE

Question 7

Pneumocystis

Answer 7

immunocompromised
Cysts and trophozoites
Clinical: pneumonia, frothy mouth