FUNGAL Flashcards
1
Q
- causes most of the fatal poisoning cases
- First, there are breathing problems and dizziness
x then comes severe vomiting, diarrhoea and dehydration - After 3 days, begins to feel better, but actually the liver is being destroyed
- Death usually at least 6 days after consumption
A
The Death Cap, Amanita phalloides
2
Q
- with other dermatologic conditions and with
fungemia in patients with indwelling catheters. - commensal lipophilic yeasts with a predilection for the sebum-rich areas of the skin.
- They are considered a part of the normal skin
flora, with presence established by 3-6 mo of
age.
A
Malassezia
3
Q
LAB Findings
- Macroscopic: dry chalky appearance
- Microscopic: clusters of thick-walled blastospores together with the hyphae produce the characteristic
- “spaghetti-and-meatballs appearance’
A
Malassezia
4
Q
— Implicated in neonatal acne
— associated with seborrheic dermatitis and dandruff.
A
- M. sympodialis and M. globosa
- M. globosa and M. restricta
5
Q
The traditional primary therapy for tinea versicolor :
A
topical selenium sulfide 2.5% applied daily for at least 10 min for a week, followed by weekly to monthly applications for several months to prevent relapse.
6
Q
- “rose gardener’s disease
- can occur as an occupational disease among farmers, gardeners, veterinarians, and laboratory Workers
- rare fungal infection that occurs worldwide both sporadically and in outbreaks.
- Etiologic agent: Sporothrix schenckii,
- exhibits temperature dimorphism, existing as a mold at environmental temperatures (25-30°C [77-86°F]) and as a yeast in vivo (37°C [98.6°F]}
A
Sporotrichosis
7
Q
- most common form of Sporotrichosis disease in all age groups.
- may either be lymphocutaneous or fixed cutaneous, the former being much more common.
- Special histologic staining such as periodic acid—Schiff and methenamine silver is required to identify yeast forms in tissues.
- Itraconazole is the recommended treatment of choice for infections outside the central nervous system.
- Younger children with cutaneous disease: a saturated solution of Potassium iodide given Orally once daily beginning at 5-10 drops 3 times per day.
- The dose is gradually advanced to 25-40 drops 3 times per day for children or 40-50 drops 3 times per day for adolescents and adults
A
Cutaneous Sporotrichosis
8
Q
- accounts for more than 75% of reported cases in children
- occurs after traumatic subcutaneous inoculation. After a variable and often prolonged incubation period (1-12 wk), an isolated, painless erythematous papule develops at the inoculation site.
- Initial lesion :extremity (adults) face (children).
- The original papule enlarges and ulcerates.
- satellite lesions follow lymphangitic spread-> multiple tender subcutaneous nodules tracking along the lymphatic channels that drain the lesion secondary nodules are subcutaneous granulomas that adhere to the overlying skin -> ulcerate-> doesn’t heal spontaneously, and these ulcerativelesions can persist for years if they are untreated.
A
LymphoCutaneous Sporotrichosis
9
Q
treatment of choice for pulmonary infections,
disseminated infections, central nervous system
disease, and infections in immunocompromised
persons in Cutaneous Sporotrichosis
A
Amphothericin B
10
Q
- A subacute or chronic infection most frequently involving the tissues of the CNS, but occasionally producing lesions
in the skin, bones, lungs or other internal organs - encapsulated, yeast-like
- reproduce by budding
A
Cryptocococis
11
Q
- exist worldwide
- Found frequently in accumulated , old pigeon droppings; has been isolated in Fort Santiago
- PIGEONS are not Clinically atfected
- Has been isolated from droppings of other birds such as parakeets and Canaries
- cryptococcosis is consiaered an AIDS-defining illness
A
C. neoformans var neoformans
12
Q
- The most common Aspergillosis causing invasive disease are
- The most common causing allergic disease are
A
- Aspergillus fumigatus and Aspergillus flavus
- Aspergillus fumigatus and Aspergillus clavatus
13
Q
- Accounts for over 90% of all yeast infections
- Grows in a wide range of temperature- can thrive up to 50°C
- Inhibited by cycloheximide
- Modes of Transmissions:
1. Respiratory
2. Direct Inoculation
3. Ingestion - Spores disseminated from humidifiers and Air conditioner filters and ducts that have accumulated moisture and from the environment
- Macroscopic appearance of fungus ball occupying a large pulmonary cavity
A
Aspergillosis
14
Q
Treatment for Aspergillosis
- Allergic aspergillosis:
- Invasive aspergillosis
- Aspergilloma
A
- Allergic aspergillosis:
> corticosteroids and itraconazole - Invasive aspergillosis :
> amphotericin B
> itraconazole - Aspergilloma
> lobectomy may benefit some
> Amphotericin B
15
Q
- Caused by Zygomycetes (Saphrophytic molds found
in the environment) - Angiotropic infection
- Occurs worldwide
- Affects immunologically or physiologically compromised hosts
- microscopic : KOH of tissues ( and with other stains):
Findings : broad, irregularly shaped, non-septatea hyphae
with right angle branching
A
Zygomycosis
16
Q
Culture Characteristics of Zygomycosis
- primary isolation media
- incubation
- how to identify
A
- primary isolation media: sabouraud s dextrose agar without cyclohexamide
- 3-5 days incubation at room temperature shows white to grey or Drownish, Gowny colonies
- identity :LPCB mount of growth
17
Q
- is a common cause of oral mucous membrane infections (thrush) and perineal skin infections (Candida diaper dermatitis) in young infants.
- caused by an ascending infection into the uterus during gestation, and invasive fungal dermatitis, a postnatal skin infection-> positive blood cultures.
A
Candidiasis
18
Q
- is a superficial mucous membrane infection that affects
approximately 2-5% of normal neonates. - C. albicans is the most commonly isolated species.
- can develop as early as 7-10 days of age.
- The use of antibiotics, especially in the 1st yr of life, can lead to recurrent or persistent thrush.
- characterized by pearly white, curdish material visible on the tongue, palate, and buccal mucosa.
- It is uncommon after 1 yr of age but can occur in older children treated with antibiotics.
A
Oral thrush/Oral candidiasis
19
Q
- Obligate extracellular organism
- Has not been cultured in vivo
- Has different mammalian hosts
- Genetically diverse (different strains) , i.e. isolate from one host will not grow in another host
- The organism is found in 3 distinct morphologic stages:
- trophozoite (trophic form), in which it often exists in clusters
- sporozoite (precystic form)
- cyst, which contains several intracystic bodies (spores)
A
Pneumocystis jiroveci (Pneumocystis Carini)
20
Q
Imaging in Pneumocystis jiroveci (Pneumocystis Carinii) shows
A
diffuse interstitial intiitrates
21
Q
Gold Standard” in the diagnosis neumocystis jiroveci
(Pneumocystis Carinii)
A
- bronchoalveolar-lavage ( BAL)
- transbronchial-biopsy
22
Q
periodic acid—Schiff (PAS) stain, dichotomous branching of hyphae is
A
Aspergillus sp.
23
Q
Culture Incubation
Time
—Dermatophytes
— Opportunists
— Systemic
A
— Dermatophytes = at least 2 weeks
— Opportunists = less than a week
— Systemic = 4 to 6 weeks
24
Q
method to observe the undisturbed growth of the fungi
A
Riddell method
25
Direct methods for yeast
- ELISA- galactomannan -
- Latex agglutination —
- RIA-
- ELISA- galactomannan - Aspergillus
- Latex agglutination — Cryptococcus
- RIA- H. capsulatum Ag
26
useful in diagnosis of mycoses in a shorter period as well as detect those fungi that are difficult or dangerous to cultivate in vitro.
DNA hybridization, PCR
27
- Bind irreversibly to ergosterol and increases membrane permeability (ionic transmembrane channels
- Prototype of the oldest antifungal class
- Side effects: “Shake & Bake”
(fever, chills, nausea, vomiting), local phlebitis, renal insufficiency, electrolyte imbalance, flushing, muscle and joint pains
Amphotericin
28
- Bind irreversibly to ergosterol and increases membrane permeability (ionic transmembrane channels)
- Only used for mucocutaneous Candida infections (anogenital & diaper dermatitis); not effective against dermatophytes; not well- absorbed from the GI tract
- Side effect: GI distres
Nystatin
29
- is resistant to all azoles
- has no activity against Aspergillus
- Fusarium solani
- Fluconazole
30
- Interfere with cell membrane synthesis via inhibition of cytochrome P450-dependent 14-a demethylase.
— This leads to accumulation of toxic 14-a-methyl sterols and prevents synthesis of ergosterol.
— Also may impair fungal triglyceride/phospholipid synthesis and inhibit fungal oxidative/peroxidase enzymes.
Imidazoles and Triazoles
31
- Interferes with cell membrane synthesis via inhibition of squalene epoxidase. This results in accumulation of intracellular squalene which is toxic to the fungus.
Allylamines and Benzylamines
32
- DOC for dermatophytes
- poor activity against many yeast
- Side effects: alteration of taste perception and occasional abnormal liver function (oral); burning, itching, erythema (topical)
Terbinafine
33
- Same as for Terbinafine but also effective against Aspergilli and dimorphic fungi, including S. schenkii
- Side effects: same as topical terbinafine
Butenafine
34
targets nucleic acid synthesis (e.g. early RNA chain termination and interruption of DNA synthesis)
Pyrimidine
35
- Extremely narrow antifungal spectrum limited to Candida species and Cryptococcus neoformans; should NEVER be given as monotherapy to prevent the emergence of resistant strains
- Side effects: nausea, vomiting, renal impairment
5-Flucytosine
36
- Inhibits fungal mitosis by interacting with microtubules
- Fungistatic against dermatophytes (primarily Tinea capitis especially in children)
- no activity against Candida or Malassezia spp.
- Side effects: GI discomfort, headache, dizziness
Griseofulvin
37
- Effective in invasive Aspergillosis in patients refractory to or intolerant of other antifungals; also effective against Candida spp.
- Side effects: headaches, fever, infusion site reactions, flushing, induration, facial swelling, pruritus, nausea and vomiting
Caspofungin
38
- prophylaxis for Candida infections in hematopoietic stem cell transplant patients, esophageal candidiasis
- prophylaxis for esophageal candidiasis
- Side effects: headache, nausea, leukopenia, anaphylaxis, liver or kidney dysfunction, phlebitis, hemolytic anemia
Micafungin
39
- Candida and Aspergillus spp.; Candidemia, esophageal candidiasis, intraabdominal Candida infections and peritonitis
- Side effects: liver toxicity, diarrhea, hypokalemia, infusion reactions
Anidulafungin
40
- a thiocarbamate that interferes with cell membrane synthesis via inhibition of squalene epoxidase (similar to allylamines)
- Dermatophytes and Tinea versicolor
- Dosing: BID application for 2-6 weeks
- Side effects: hypersensitivity reactions
Tolnaftate
41
- a hydroxypyridone that chelates polyvalent cations that have important functions in fungal cytochromes, catalases and peroxidases; inhibits espiration, blocks amino acid transport, and alters cell membrane permeability
- Brand name: Stieprox (liquid shampoo)
- Seborrheic dermatitis and control of tinea capitis
- Dosing: use as shampoo — Side effects: irritation
Ciclopirox olamine
42
- reduces cellular adhesion in the stratum corneum, facilitating shedding of fungi; antimitotic properties
- Scaling, flaking, and itching of the scalp due to dandruff and seborrheic dermatitis
- Side effects: irritation
Selenium sulfide
