aspergillus Flashcards
who are at risk for aspergillus infection?
rarely infect normal human host
usually immunocompromised patients
what is the saprophytic cycle of aspergillus?
conidia released from conidiospores
conidial swelling ad germination
hyphal extension forming mycelia
what is the pathogenic cycle of aspergillus?
airborne conidia constantly inhaled by humans
in immunocompromised patients they may evade the host defences and grow invasively
extensive hyphal growth in the lungs
colony growth
what toxins do aspergillus species produce?
aflatoxins
what are aflatoxins?
poisonous carcinogens and mutagens
toxic to a wide range of eukaryotes
what is invasive aspergillosis symptoms?
fever cough haemoptysis chest pain neutropenia
what are the symptoms of cutaneous aspergillosis?
single or multiple plaques or papules which may be tender
often with a central necrotic ulcer
what is chronic aspergillosis?
growth of aspergilli in lung cavities
formation of aspergilloma which can result in haemorrhage
what are the symptoms of chronic aspergillosis?
cough
blood stained mucus
what is allergic aspergillosis?
allergic reaction to aspergillus antigens
colonisation of lung tissue
what are the symptoms of allergic aspergillosis?
wheezing eosinophilia chest pain fever coughing up brown mucus plugs
what specimen type is needed for aspergillus diagnosis?
sputum
bronchoalveolar lavage
how is microscopy used in the diagnosis of aspergillus?
lactopheal cotton blue microscopy
calcofluor white fluorescence microscopy
what media are used in the diagnosis of aspergillosis? what conditions are needed?
sabouraud dextrose agar
35-37 degrees in air from 5 days to 6 weeks
second plate incubated at 42-45 degrees to prevent candida species growth
what is the treatment for invasive aspergillosis?
voriconazole is the antifungal of choice
other antifungals can also be used
