Lecture 10: Fungi and Infections PDF

Lec 10  Mycology: is the study of fungi and their functions in nature. Fungi: not contain chlorophyll, but have cell walls, budding ( unicellular), filamentous structures, and produce spores. Medical mycology: disease cause by fungus. Enumerate types of Mycotic disease: 1. Hypersensiti...

Lec 10  Mycology: is the study of fungi and their functions in nature. Fungi: not contain chlorophyll, but have cell walls, budding ( unicellular), filamentous structures, and produce spores. Medical mycology: disease cause by fungus. Enumerate types of Mycotic disease: 1. Hypersensitivity: an allergic reaction to molds and spores. 2. Mycotoxicosis: poisoning of human and animals by fungi. 3. Mycetismus: the ingestion of pre-formed toxin. 4. Infection: pathogenic fungi which cause infections. ❖ Most common pathogenic fungi do not produce toxins.  CANDIDIASIS (Candida albicans) The infections caused by all species of Candida are called candidiasis. Candida albicans: is important in clinical practice to species Candida because drug resistance and treatment varies with species.  Disease cause by Candida Oral Candidiasis Also known as moniliasis Or thrush or Candidiasis. Caused by the infection with yeast like fungus Candida albician.  Symptoms of Oral Candidiasis 1. White bumps on tongue, cheeks, gums, or tonsils. 2. Bleeding when bumps are scraped. 3. Pain at bump sites. 4. Dry, cracked skin at mouth corners. 5. Difficulty swallowing.  Who is at Risk 1. Newborn. 2. Adult with Diabetic. 3. Denture Users. 4. Antibiotic users or Chemotherapy Treatment. 5. Drug Users. 6. Poor Nutrition. 7. Immune Deficiency.  DIAGNOSIS 1. Wet Mount 2. Dermal Hypersensitivity 3. Direct fluorescent microscopy 4. Serology 5. Culture and biopsy 6. Molecular TREATMENT One of the first chemotherapeutic agents (oral iodides) was an anti-mycotic used in 1903, Development of anti-fungal agents.  Cryptococcosis (Cryptococcus neoformans) 1. Cryptococcus: A genus of fungi that grow as yeasts. 2. Common Manifestations: Meningitis (most common), pulmonary infections. 3. Infection Type: Can be subacute or chronic. 4. Highly Fatal Condition: Meningoencephalitis caused by C. neoformans.  Initial Symptoms: Vision problems, lethargy, headache. Progression: Delirium, neck stiffness, coma, and potentially death. Diagnosis: Requires a spinal tap (lumbar puncture). CSF Examination: o Characteristic chemistry of CSF. o Evidence of the organism (India Ink preparation). o Serologic assay for C. neoformans antigen. Cause of Death: Often due to cerebral edema and increased intracranial pressure. Ecological Niche: Found in pigeon and chicken droppings.  SUPERFICIAL MYCOSES are fungal infections affecting the outer layers of skin, hair, and nails. They do not invade living tissues. The fungi causing these infections are called dermatophytes or keratinophilic fungi. These fungi produce enzymes that break down keratin. Tinea: means ringworm refers to several types of these infections: 1. Tinea corporis: Ringworm, small body lesions. 2. Tinea pedis: Athlete's foot, toe webs and soles of feet. 3. Tinea unguium (onychomycosis): Nail infection, lifelong. 4. Tinea capitis: Hair infection in children. 5. Tinea cruris ("jock itch"): Groin infection. 6. Tinea barbae: Infection in bearded areas. 7. Tinea versicolor: Blotchy, itchy skin discoloration.