PMI02-2010 Fungal infections Flashcards
What is the difference between yeasts and moulds?
Yeast is unicellular, moulds are multicellular
Yeasts reproduce by budding, but moulds reproduce using specialised spore structures
Yeasts may produce hyphae and pseduohyphae, but moulds only produce hyphae
How are pseudohyphae formed?
produced by bud elongation
How are true hyphae formed?
produced by apical extension
Which fungi are commensal to humans?
Yeast
Candida alicans are commensal to the oral cavity and the gut
Are there commensal moulds to humans?
no
What factors predispose to candidiasis?
Age (infancy and elderly) Endocrine disorders like diabetes Cancer Drug addiction Antibiotics, corticosteroids and immunosuppression Intravenous catheters
How does Candida albicans cause infection?
It can adapt to changes in environments It can adhere to different surfaces Produce destructive enzymes Change in cellular morphology Production of biofilm Blocks oxygen radical production and degranulation of neutrophils Toxin production
What is cryptococcus?
A yeast that grows in things like pig droppings
Can cause sub acute to acute pulmonary infections through inhalation of spores
What is a cryptococcus infection?
Exists only in the yeast form, no hyphae produced
Their major virulence factor is their ability to produce a capsule which is protective, as it prevents phagocytosis
Why are commensal moulds only exogenously acquired?
there are no commensal mould
What factors predispose to mould infections?
History of trauma at the site of infections
Other underlying diseases that may influence the persons susceptibility to disease
What are dermatophytes?
Dermatophytes are a family of fungi that use keratin as a substrate
What are dermatophytes referred to clinically?
tinea
What are risk factors of tinea capitis?
scalp infections are common before puberty
What inhibits fungal growth in tinea capitis?
sebum production
