Aspergillus  Aspergillus is a filamentous, hyaline mold.  It can grow on dead leaves, stored grain, and other decaying vegetation.  Large numbers of species present in genus Aspergillus but about 20 species reported as causative agent of opportunistic infection in man. The main species are : A. fumigatus, A. flavus, A. niger, and A. terreus.  Its pathogenicity is low, and healthy individual has a high resistance to infection,  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.

Pathogenesis of Aspergillus infection  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.  Hyphae after maturation can invade blood vessels, resulting in vascular inflammation and thrombosis, necrosis and hemorrhage.  Macrophage and granulocytes are the major immunoregulatory cells involved in host defense against infection.

Laboratory diagnosis 1. Direct examination: 2. The most useful media for isolation from clinical material are modified Sabouraud's agar and malt extract agar with antibiotics. 3. Serological test Immunodiffusion test: one or more precipitin bands suggest active disease. IgG antibody is present in most patients with Aspergilloma. IgG and IgE antibodies are present in most patients with allergic bronchopulmonary Aspergillosis. Serologic test are less useful for diagnosis of invasive disease.

Zygomycetes  The zygomycetes are a group of fungi, widely distributed in nature as environmental inhabitants.  The genera of fungi of medical importance that are included within the class Zygomycetes are: Genus Rhizopus Genus Mucor Genus Absidia  These fungi grow rapidly  Members in class Zygomycetes cause zygomycosis (mucormycosis) in a specific group of compromised hosts.  Human usually become infected through inhalation of air borne spores (sinus and pulmonary diseases) or through ingestion of contaminated food stuffs (gastrointestinal disease).

Clinical types 1. Rhinocerbral: this is the most commonly occur. 2. Pulmonary. 3. Cutaneous. Occur secondary to truma and soil contamination, in burns. 4. Disseminated: May involve any organs, occurring from secondary spread from the lung, the sinus or rarely from the gastrointestinal tract. Because of the rapid growth of the etiological agents, and simple nutritional requirement, the organisms are rarely cultured during life, but are seen in histologic preparation of tissues as broad, non septate irregular hyphae in thrombosed vessels or sinuses.

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. 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. All of these induce or show a similar clinical picture. 1. Eumycotic Mycetoma: cansed by species of fungi E.x.p: A. Madurella Mycetomatis B. Acremonium Kiliense. 2. Actinomycotic mycetomas: caused by member of actinomycete E.x.p: A. Actinomadura madurae B. Nocardia asteroide s. Laboratory diagnosis Microscopic examination of pus, exudates, or biopsy material reveals the presence of the grains, which are the primary diagnostic indicators.

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

Chromomycosis (chromoblastomycosis) Is alocalized chronic mycosis of skin and subcutaneous tissues. Etiology Caused by dematiaceous, pigmented or dark colored fungi. The main species a. Phialophora verrucosa. b. Fonsecaea pedrosoi.