L9 Fungus/ antifungals Flashcards
Basic Characteristic of Fungi - distinguish from bacteria
- eukaryotic
- obligate or faculative aerobes
- chemotropic - secrete enzymes then absorb nutrients
- mycotoxins are ingested - not usually live bacteria
- sexually repoduction
- no NOT Gram Stain
- Calcofluor or silver stain work for most (Periodic acid Schiff (PAS) also)
- 80S ribosom-
Components of Fungal cell walls and membrane
Cell Wall:
- B-glucans
- mannoproteins
- Chitin
Important immune factors in fungal disease
- neutrophils
- CD4+ cells
- usually the two most important, and if missing lead to bad fungal disease
Aflatoxin
- made by aspergillus
- worst mycotoxin
- causes liver cancer
- most potent carcinogen
Candidia
- yeast or mold?
- characteristics
- clinical manifestation
- treatment
Candidia
- Yeast
- most common mycoses in ppl
- Candidia albicans - lives in mouth, skin, vagina
- normal flora, integrity of epithelial, and macrophages keep them in place
- CD4+ and neutrophils are important to prevent systemic
Clinical Manifestations:
- Thrush
- Vulvovaginitis
- Cutaneous
- Systemic - problem with phagocytes - lesion on eyes, heart, meninges
- Treatment:
- topical Nystatin
- Oral/tropical azoles
systemic - azoles, echinocandins, and amphotericin B
Cryptococcus neaoformans yeast or mold? - characteristics, pathogenesis - clinical manifestation - diagnosis - treatment
- yeast
- worldwide
- usually occurs in immunocompromised (gattii tropical trees normal host)
- pathogenesis - polysacc capsule prevents phago
- produces melanin to protect from ROS
- Clinical manifestations
- inhaled thru the lungs
- spreads to CNS
- pneumonia and meningoencepahlitis
- Low CD4+ is the main problem
- Diagnosis
- India INk
- serology for capsul antigen
- culture
- treatment
- Amphotericin + 5-flucytosine followed by fluconazole
Dermatophyes
- yeast or mold? 3 types
- characteristics, pathogenesis
- clinical manifestation
- diagnosis
- treatment
Dermatophytes
- Mold
- lives and feeds on keratin
- zoophilic - animal - ring worm - microsporum canis
- geophilic - soil
- antrhopophilic - most common dermatophye
- trichophyton rubrum - athletes foot and jock itch
- oncychomycosis - nail fungus
- Infects superficial keratin layer of skin - eats keratin
Test- scape skin, microscope and culture
- treatment
- topical - imidazoles
- oral - terbinafine or azoles
Pneumocystis jiroveci
- characteristics, pathogenesis
- clinical manifestation
- treatment
Pneumoncystis jiroveci
- pneumonia in T-cell deficient
- Characteristics
- lacks ergosterol
- creates pneumonia
- T-cell suppressed patients
- Can be prevented by giving TMP/STX - Bactrim CD4 <200
Aspergillus
- yeast or mold?
- characteristics, pathogenesis
- clinical manifestation
- diagnosis
- treatment
Aspergillus
- Mold
- Characteristics - Aflatoxin
- inhale spores, they infect lungs, enter blood, dissemiate into the brain
- Clinical
- wide spectrum of lung issues - ABPA, tracheobronchitis, aspergilloma - fungus ball, disseminated
- diagnosis
- growth on samples, septate hyphae, galatomannan antigen in blood
- treatment
- Ampho
- Azoles - not fluconazole
- Echinocandins
Zycomyses
- yeast or mold?
- who does it affect
- main clinical
- treatment
Mucor, Absidia, Rhizopus, Rhizomucor
Zycomycoses
- non-septate mold
- Immunocompromised, metabolic disorder, high free iron
- Clinical
- sticks to blood vessels and causes clots and infarction
Most Common - rhinocerebral disease - nose, sinus, brain, fatal
- Treat with ampho B, posaconazole oral, surgery
Sporotrichosis
(Sporothrix schenkii)
- yeast or mold?
- clinical
- dimorphic - mold in environ, yeast at body temp
- inoculated into skin - rose bush - exposure to soil/plant
- non-healing inflammed nodules spread thru lymph
dematiaceaous molds
Fungal meningitis 2012
- melanized cell walls - black pigment
Histoplaams capsulatum
- dimorphic
- ohio/Mississippi rivier valey
- histoplasmosis - inhalled from bird droppings/roosts
- mediastinal granuloma/fibrosis
- Chronic or cavitary pulmonary histoplasmosis
- 90% asymptomatic
Ampho B or Itraconazole
Coccidioides immitis
Dimorphic
- valley fever -
- SW U.S.
- endospores
- self limiting flu like but can be fatal
- resembles TB clinically, immuno compromised more susceptible
- Ampho B
Amphotercin B
- polyene
- fungalcidal
- binds to ergosterols in membrane = increase permability- lyse cell
- nephrotoxicity
- Infusion related effects (rigors, fever);
Hypokalemia and hypomagnesemia
Severe candida, aspergillus, cryptococcus, coccidiodes immitis
