fungi

• general characteristics of fungi

  eukaryotic, aerobic, thermotolerant, rigid cell wall containig chitin, cytoplasmic membrane has a high ergosterol content
• what culture medium is used for fungi?

  sabouraud dextrose agar
• dimorphic fungi


  histoplasma spp and sporothirx
• yeast-like fungi

  candida spp, pneumocystis jirovecii
• filamentous fungi/moulds?


  dermatophytes, aspergillus spp
• yeast example

  cryptococcus
• yeast-like fungi example?

  candida albicans
• yeast-like cells grow partly as yeast and partly as elongated cells called what?

  pseudohyphae
• how do yeast-like cells reproduce?

  budding
• moulds or filamentous fungi are multicellular
• how do mould / filamentous fungi reproduce?

  longitudinal extension
• example of a mould or filamentous fungi?

  aspergillus fumigatus
• saprophytic

  grow on dead or decaying matter
• hyphae


  tubules made up of fungal cells attached end to end
• dimorphic fungi

  can grow either as a yeast or a mould depending on environmental conditions
• moulds in environment at 25-30
• yeasts in human tissues at 35-37
• why are most fungi not pathogenic to humans

  high levels of innate immunity and presence of normal flora on skin
• pathogenic fungi can be divided into two groups, what are they?

  primary pathogens (can infect healthy individuals ex: cryptococcus spp.) and opportunistic pathogens (infect compromised individuals ex: candida spp.)
• superficial fungal infection example

  dermatophytes, thrush
• subscutaneous fungal infection example?

  sporotrichosis
• systemic fungal infection example?

  cryptococcal meningitis
• hypersensitivity fungal pathogenicity

  aspergillus-induced asthma
• toxins fungal pathogenicity

  wild mushrooms can cause various symptoms from minor to severe
• what do dermatophytes cause

  ringworm / tinea
• 3 genera of dermatophytes

  trichophyton spp. / epidermophyton spp / microsporum spp
• trichophyton causes athlete's foot (tinea pedis)
• epidermophyton causes tinea of skin and nails
• microsporum causes tinea of the scalp
• treatment of tinea?


  oral terbinafine, topical antifungals, keratolytic agents
• keratolytic agents

  salicylic acid or boric acid - designed to dissolve skin flakes and scales
• dimorphic fungi example

  histoplasma capsulatum
• what antifungal would you use to treat local osteoarticular subcutaneous mycoses?

  itraconazole
• what antifungal would you use to terat disemminated or pulmonary mycoses?

  amphotericin B
• how does candida appear after gram staining

  positive, but much larger than bacteria
• candida skin infections

  plaque-like lesions, found in warm moist areas
• risk factors for candida skin infection?

  antibiotics, steroids, pregnancy, immunosuppression
• treatment for candida skin infection?

  topical antifungal agents - clotrimazole

  oral: fluconazole
• mucosal candida infection


  thrush
• how does thrush present?

  discrete white patches on mucosal surfaces