Aspergillus
1. Aspergillus is a filamentous, hyaline mold.
2. Its pathogenicity is low, and healthy individual has a high resistance to infection,
infection occur in indvdual with impaired immunity .
3. Aspergillosis is not contagious and source of infection is exogenous.
Clinical types
1) Pulmonary divided in to:
A. Allergic broncho pulmonary.
B. Colonizing (fungus ball)
C. Invasive forms.
2)
Cutaneous.
3)
Otomycosis.
4)
Central nervous system.
5)
Nasoorbital.
6)
Endocardial.
7)
Disseminated.
8)
Mycotoxicosis: is poisoning by ingestion of toxins of fungal origin (Mycotoxin) in foods
which have been damaged by the growth of toxin producing molds. Aflatoxin B is one of
the most potent chemical carcinogen produced by mold of aspergillus in fod supply
Pathogenesis of Aspergillus infection
1. The major portal of entry for infection is
the respiratory tract. The small, air borne
spores reach the bronchial tree, including
the alveoli, where the fungus establishe
colonization, and in
immunocompromised patients can
initiate invasive disease.
2. Hyphae after maturation can invade
blood vessels, resulting in vascular
inflammation and thrombosis, necrosis
and hemorrhage.
3. Macrophage and granulocytes are the
major immunoregulatory cells involved in
host defense against infection.
Laboratory diagnosis
1. Direct examination:
for specimen apear
as branching hyaline huphae
2. The most useful media for isolation from
clinical material are modified
Sabouraud's agar and malt extract agar
with antibiotics.
3. Serological test
A. Immunodiffusion test: one or more
precipitin bands suggest active disease.
B. IgG antibody is present in most patients
with Aspergilloma .
C. IgG and IgE antibodies are present in
most patients with allergic
bronchopulmonary Aspergillosis.
D. Serologic test are less useful for
diagnosis of invasive disease.
Zygomycetes
1. Wide environmental inhabitants .
2. These fungi grow rapidly
3. Members in class Zygomycetes cause zygomycosis (mucormycosis) in a specific group
of compromised hosts :
4. Human usually become infected through
A. inhalation of air borne spores (sinus and pulmonary diseases) or
B. through ingestion of contaminated food stuffs (gastrointestinal disease).
Clinical types
1. Rhinocerbral: this is the most commonly occur. cause massive tissue destruction .
2. Pulmonary.
3. Cutaneous.
4. Disseminated: May involve any organs, occurring from secondary spread from the lung,
the sinus or rarely from the gastrointestinal tract.
seen in histologic preparation of tissues as broad, non septate irregular hyphae in
thrombosed vessels or sinuses.
Treatment :
Subcutaneous mycoses
The three mycoses of this type are:
1. Mycetoma.
2. Sporotrichosis.
3. Chromomycosis.
The etiological agents of these diseases, all have a saprophytic existance in nature. The
usual route of infection is through wounds.
1. Mycetoma (Madura foot, maduromycosis)
The disease is characterized by three signs:
1. Swelling (tumor like lesion)
2. Sinus tract formation.
3. Visible granules in the pus draining from sinus tract.
Etiology
Mycetomas are caused by various actinomycetes (higher bacteria) and true fungi. show a
similar clinical picture.
A. Eumycotic Mycetoma: cansed by species of fungi E.x.p:
A. Madurella Mycetomatis
B. Acremonium Kiliense.
B. Actinomycotic mycetomas: caused by member of actinomycete E.x.p:
A. Actinomadura madurae
B. Nocardia asteroides.
Laboratory diagnosis
Microscopic examination of pus, exudates, or biopsy material reveals the presence of the
grains, which are the primary diagnostic indicators.
If it show septate hyphae it is due to Eumycotic Mycetoma or if it show f ilamint it is due to
Actinomycotic mycetomas
2. Sporotrichosis
Is a chronic, subcutaneous, lymphatic
(rarely respiratory) mycosis. In some
untreated cases, it may become a
generalized infection and involve bone, joint,
C.N.S.
Clinical types
1. Cutaneous lymphatic
2. Cutaneous non-lymphatic.
3. Disseminated
Etiology
Sporothrix schenckii it is true dimorphic
fungus .
Chromomycosis (chromoblastomycosis)
Is alocalized chronic mycosis of skin and
subcutaneous tissues.
chaictrised by
watery ulcerated and crusted lesion . May be
flat or have raised surface apear as
cauliflower .
Etiology
Caused by dematiaceous, pigmented or dark
colored fungi. The main species
Phialophora verrucosa.
Fonsecaea pedrosoi.