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56 Cards in this Set
- Front
- Back
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What are the three types of fungal infection? |
1. Superficial 2. cutaneous 3. systemic/deep |
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Describe protection from skin. |
1. physical barrier against fungal infections 2. protect underlying tissues |
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Why more bacteria growth found on wet skin than dry skin? |
bacteria need water for growth so prefer wet/moist areas |
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Where does superficial mycoses occur? |
stratum corneum of epidermis and hair shafts
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give one example of superficial mycoses and the fungi responsible. and what are the symptoms? |
Pityriases versicolour by malasseia furfur symptoms : - flaky skin - loss of pigmentation - hyperpigmentation |
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What does malasseia furfur look like under microscope? |
spaghetti and meatballs |
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Where does pityriases versicolour affect on the body |
mainly trunk and proximal part of limbs |
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What causes malasseia furfur to turn off commensalism to pathogenic? |
unknown stimuli |
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What does cutaneus mycoses affect? |
keratinized layers of skin, nails and hair |
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what is the abundance of keratinocytes in skin? |
90% |
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What species of fungi are usually responsible for cutaneous mycoses? |
dermatophya |
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what is the source of infection of cutaneous mycoses? |
infected animals, soil, humans |
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hoe does one get infected with cutaneous mycoses? |
come in contact with arthrospores |
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What are the common disease regarding cutaneous mycoses? |
Tinea/Ringworm |
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How does arthrospores infect the body? |
Arthrospoers attach and invade and colonize the keratinized layer of skin, nail and hair. Does not invade living tissues. |
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How does dermatophytes obtain nutrients? |
dermatophytes have keratinase enzyme that can use keratinocytes as nutrition source |
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what are the symptoms to dermatophytosis? and what causes these symptoms |
allergic and inflammatory (non contagious) response of skin due to production of metabolic end products
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What does the inflammatory response look like? |
red raised circular lesions flaky, itchy |
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What is the most common type of tinea? |
tinea corporis |
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What does tinea pedis effect are wcutaneous mycoses and what are the symptoms of tinea pedis? |
tinea pedis affect the food itching toe web maceration of skin redness of 1st and 2nd toes minima inflammation |
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how is tinea pedis spread? |
coming in contact with desquamated skin cells in carpets/shoes |
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What is the diagnosis of dermatophytosis? |
1. clinical assessment 2. collect skin swab (from ring where viable and growing cells are) 3. culture on sabourands agar (SAB) 4. using wood's light |
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What is SAB and what are its characteristics? |
SAB = sabourands agar - low pH - high sugar content |
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what are the uses of SAB? |
1. growth of fungi indicated by pigmentation 2. see formation of mycellium on plate |
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What is wood's light? How does it work? |
form of diagnosis for fungal infections e.g. dermatophytosis work by shining UV light causing fluorescence of infected area (scalp/skin) |
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where does microsporum canis effect on the body? |
mainly scalp, and glabrous skin
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what is the source of infection of microsporum canis? |
infected cats and dogs |
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What is the fungi that causes vaginal thrush and balantis? |
candida albicans (yeast)
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what are the symptoms of vaginal thrush?
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thick milky curd-like discharge |
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what are the symptoms of balantis? |
inflammation of foreskin/head of penis red lesions |
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What are the causes of vaginal thrush? |
1. use of broad spectrum antibiotics - kill normal vaginal flora e.g. decrease in lactobacillus, increase in pH overgrowth of candida albicans. 2. oral contraceptives/pregnancy - increase in glycogen content in blood |
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what is the normal pH of the vagina? |
3.5 - 4.5 |
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What is the diagnosis of vaginal thrush? |
lower vagina swab examine on SAB |
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What are the treatments for candida albicans for male and female? |
male - treatment only if symptomatic (balanitis) female - antifungal topicals |
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Why does males need to test for diabetes if they have balanitis? |
diabetes = increase blood sugar content favourable towards growth of candida albicans |
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How does a baby contract oral-candidasis? |
1. natural birth, contracted via birth canal 2. breastfeeding 3. use of broad spectrum antibiotics |
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How does an adult contract oral-candidasis? |
with immuno-suppressed systems e.g. HIV/AIDS, transplant, diabetes |
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What is the symptom of baby oral-candidasis? |
white creamy-looking pseudomembrane in inner mouth |
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what fungi causes most systematic fungal infections? |
cryptococcos neoformans |
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What do cryptococcus neofoman look like? |
encapsulated yeast |
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what is the function of the capsule on cryptococcus neoformans? |
prevent attack of immune system getting to cell |
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What is cryptococcus neoformans transmitted? |
by inhalation of airborne cells e.g. bird faeces |
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what happens when an immunosuppressed person contracts cryptococcus neoformans? |
more likely to have fungal meningitis |
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What are the immediate and late stage symptoms of fungal meningitis? |
early - headache, nausea late - coma, loss of vision |
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What is the diagnosis for cryptococcus neoformans? |
1. India Ink Stain 2. fluorescent stain 3. antibody-antigen latex agglutination test |
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How does the antigen-antibody latex agglutination test work? |
blood from patient contains antigen of cryptococcus neoformans. mix blood with antibodies to allow agglutination latex allow the visualization of agglutination |
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What is the advantage of the antigen-antibody agglutination test? |
can test for cryptococcus neoformans 22 days before onset of symptoms. |
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What are the 3 types of antifungal agents used to treat cryptococcus neoformans? give drug example of each class |
1. polyenes - amphotericin B 2. azoles 3. flucytosine |
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what is the mechanism of polyenes? |
1. polyenes bind to ergosterol in the cell membane 2. insert itself into the membrane 3. cause leakage of cations |
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What are the side effects of polyenes? |
renal toxicity if polyene bid to host cholesterol --> TOXIC |
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What fungal infection is polyene used to treat? |
systematic infections |
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what is the mechanism of azoles? |
1. block synthesis of ergosterols 2. accumulate toxic intermeiates within cell 3. cause cell stress |
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What fungal infection does azole treat? |
superficial and cutaneous |
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what is the mechanism of flucytosine? |
inhibit DNA and RNA synthesis |
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What fungal species does flucystine act upon? |
candida albicans cryptococcus neoformans |
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What is done to oversome flucysteine resistance? |
use flucytosine in combination with amphotericin B (polyenes) |
