aspergilius

• Mycetomats


  • Slowly progressing
  • Rapidly progressing
• Colour of granules


  • Black to white
  • Yellow
• Microscopic exam


  • Thick hyphae spores
  • Thin fragmented filaments
• Culture


  1. Sub-culture

  2. Blood agar media

  3. Sabouraud agar
• After inhalation of spores, in the lung, the alveolar macrophages are able to engulf and destroy the conidia
• If the conidia are not destroyed, they swell and germinate to produce hyphae that have a tendency to invade pre-existing cavities or blood vessels
• The type of disease and severity depends upon the physiologic status of the host and the species of Aspergillus involved
• Forms of aspergillosis


  • Allergic form
  • Aspergilloma and extra pulmonary colonization
  • Invasive aspergillosis
• Mycotoxicosis can occur due to ingestion of contaminated foods
• Mycetoma can be caused by A. nidulans
• Allergic bronchopulmonary aspergillosis


  IgE Abs to the surface of Ag of Aspergillus conidia elicit an immediate asthmatic reaction
• Aspergilloma and extra pulmonary colonization

  When inhaled conidia enter an existing cavity, germinate, and produce abundant hyphae in the abnormal pulmonary space
• Patients with previous cavity disease like tuberculosis, sarcoidosis, emphysema, are at risk of aspergilloma
• Some patients with aspergilloma are asymptomatic, while others develop cough, dyspnea, weight loss, fatigue, hemoptysis
• Cases of aspergilloma rarely become invasive
• Localized non-invasive infection (colonization) by Aspergillus spp may involve the nasal sinuses, the ear canal, the cornea or nails
• Sinus aspergillosis is commonly caused by A. flavus in Sudan, and A. fumigatus
• Otomycosis is mainly caused by A. niger, but also A. flavus, terreus, fumigatus
• Endophthalmitis can follow eye surgery
• Invasive aspergillosis


  Develops as an acute pneumonic process with or without dissemination
• Patients at risk of invasive aspergillosis are those with leukemia, lymphoma, bone marrow transplant recipients, and patients taking corticosteroids
• Symptoms of invasive aspergillosis include fever, cough, dyspnea and hemoptysis
• Hyphae invade the lumens and walls of blood vessels, causing thrombosis, infarction and necrosis
• From the lung, the disease may spread to the gastrointestinal tract, kidneys, liver, brain, heart and other organs, producing abscesses and necrotic lesions
• Aflatoxins


  Naturally occurring mycotoxins produced by many species of Aspergillus, most notably Aspergillus flavus and Aspergillus parasiticus
• Aflatoxins are toxic and among the most carcinogenic substances known
• After entering the body, aflatoxins may be metabolized by the liver to a reactive epoxide intermediate or be hydroxylated and become the less harmful aflatoxin M1
• High-level aflatoxin exposure produces acute hepatic necrosis, resulting later in cirrhosis, and/or carcinoma of the liver
• Acute hepatic failure due to aflatoxin exposure is made manifest by hemorrhage, edema, alteration in digestion, absorption and/or metabolism of nutrients and mental changes and/or coma
• At least 13 different types of aflatoxin are produced in nature
• Aflatoxin B1 is considered the most toxic and is produced by both Aspergillus flavus and Aspergillus parasiticus
• Aflatoxin G1 and G2 are produced exclusively by A. parasiticus
• The presence of Aspergillus in food products does not always indicate harmful levels of aflatoxin are also present, but it does imply a significant risk in consumption
• Specimens for laboratory diagnosis of aspergillosis


  • Sputum, other respiratory specimen, lung tissue biopsy
  • Blood samples (for serology only)
  • Swabs (ear, eye, CSF, sputum)