Fungal infection Flashcards
List characteristics of mushrooms, such as their place in the Kindom tree, their role in nature, and how they digest nutrients
Mushrooms are in the eukaryota tree, very close to animals (humans)- quite similar
They can be food, recyle and symbiose, and antimicrobial AND human pathogen
Most of fungi have not been discovered-only about 5%, but they exist everywhere (spored in air constantly)
Importantly, fungi secrete enzymes in the environement that dissolved what they live in, making a dead food gloob they then intake
What are the 3 main types of disease caused by fungi?Give a quick description of the first 1
Allergy, mycotoxicoses, Mycoses
Allergy are world wide problem-as fungal sporea are present everywhere, and are very diversified-and they have been showed to cause allergy-Rhinitis, asthma, dermititis, and allergic broncho pulmanory aspergillosis (ABPA)-caused by asperigillius fumigantus-2.5% of ashtmatics
What is mycotoxicosis? What are they caused by? What are some reaction? and the worse offenders
Mycotoxicosis-Toxic reaction due to inhalation of mycotoxins (they are secondary metabolites of mould that have toxic effects). Symptoms are breathing problems, dizziness, severe vommiting, diarhoe, dehydration-therapy is usually just gastric lavage or liver transplant
they can also be uptaken during eating-poison mushrooms, or Psychadelic mushroom (psilocybin)
But also Aflatoxin, produced by asperigillius flavorus, is a major carcinogenic compound (in grain in africa)
What are mycoses? Where are the 4 levels they can affect humans? Describe the first one
Mycoses are fungi that actually grow on/in humans-pathogens
Can be Superficial, cutaneous or subcutaneous and systemic
Superficial mycoses-nearly only cosmetic effects of skin or hair shafts-no living tissue is invaded, and there is no response from host
eg: Malassezia Globbosa cause dandruff by producing oleic acid
What are cutaneous mycoses? What do they live on/in? give exemples
Cutaneous mycoses, or dematophytes, keratynocytes and fungi producing enzymes (keratinase) capable of using Keratin to make food-and cause inflammation by host response to the by products
Eg: Ringworm, Tinea +location of body-causes a ring shaped redness on many parts of body => can get bad, like tinea capitis (scalp) can spread fast and is very common (25% of african children-and disfuguring, stigma, etc)
Tinea pedis-atheltes foot (loose skin between toe nails), tinea corporis-all over body
What are subcutaneous mycoses? Describe them and give exemples
Subcutaneous mycoses can survive in the body-cause chronic, localised infection in skin and any subcunatenous tissue following traumatic implantation if aetiologic (causing) agent -rare but increasingly common in war wound-large trauma, unwashed and stuff
Eg: sporotrichosis-can transmitted by scatches in brazil
Describe systemic mycoses, the 2 categories, and exemples.
Systemic mycoses go to the blood and take over the body-can be either primary (establish in healthy individual), or opportunistic (need comprimised host to go)
systemic fungi infection have very high rate of mortality- more people die of top 10 fungi than malaria or TB
Big exemple is candida-yeast. over 100 species that can colonise humans (opportunistic but can be prinary)-can infect oral, GI, URT, LGT, LUT, Skin, nails
usually primary in oral, GI LG/UT, skin, and opportunistic for superficial, mucosal, systemic
Superficial candida-mouth throat, lungs, and more-due to impaired epithelial barrier-all ages. easy treatment
mucosal-very symptomatic-normatlly when v young or old, Seen with HIV-but very opportunistic
Blood stream infection seen in hospital
Systemic-not seen in healthy, but can be due to chemi therapy, gut surgery, catheters-very bad and hard to distinguish from other systemic infections
Explain diagnosis methods for fungi infections
Fungi have few and rare symtoms that are specific to them-usually based on suspicioin (immuno supressed, travel, etc)
Diagnosis tools are usually microscopy-gold standard, but need to be able to sample and only if enough fungi
Culture-slow, prone to contamination, requires skilled collection
Others are AB and AG based ones-specific to fungi (glucan, mannan, enolase, proteinase), or PCR
What do antifungal drugs target? List method of action and exemples or drugs. Explain anto-fungi resistance
Target membrane function (pylogenes), nucleic acid synthesis (s flucytosine), cell wall synthesis (echinocandins) and membrane biosynthesis (azoles, terbinafine, etc) mainly-but because fungi similar to human its hard
But resistance is arising in fungi too-especially in those used to treat humans and animals/plant-Azoles are used as pesticides, and therefore resistance is acquired in the wild-then when comes to human resistant
