FUNGI Lecture Notes 2024-2025 PDF

Block 1.2 lectures 2024-2025 lecture Highlighter key Writer Reviewer D...

Block 1.2 lectures 2024-2025 lecture Highlighter key Writer Reviewer Doctor explanation Abbreviation Key information Book >> >> Ali Alsulaiman Lein Alshafei 221-222-223 notes References Student explaintion Deleted  Mycology By Dr. MervatAbdel-Aziz Medical Microbiology, Immunology & Infection Control  The study of fungi is called mycology. True nuclear membrane A fungus is a member of a large group of eukaryotic organisms, they are normally harmless to humans. Except , if the patient is immunocompromised , severe immunodeficiency it will be pathogenic eg. HIV patient , taking immunosuppressant medication for a long time  very important Larger than bacteria Fungi has membrane bound organelle like human cell except one bacteria , mentioned later Gives strength to the cell members. *Asexual by fragmentation and budding unfavorable condtion —> separation of the cell. *Sexual by fusion of 2 cells and give us one cell. Organic carbon source : lipids What is the benefit from knowing that Fungi are Eukaryotic ? Anaerobe : complete absence of Oxygen That Antifungal drug is highly toxic , and that’t why most of Aerobe : presence of Oxygen Antifungal drugs are topical, in the form of cream etc.  GENERAL FEATURES  Most fungi are obligate aerobes; some are facultative anaerobes; but none are obligate anaerobes. Most fungi are obligate aerobes, meaning they require None of the fungi are obligate anaerobes because their oxygen for their metabolism. Some fungi can adapt to metabolic processes rely on oxygen for efficient energy anaerobic conditions as facultative anaerobes, allowing production through aerobic respiration. they cannot them to survive without oxygen but preferring it when thrive in completely oxygen-free environments. available. All fungi require a preformed organic source of carbon. The natural habitat of most fungi is the environment. An important exception is Candida albicans, which is part of the normal human flora. Fungi are harmless except Candida albicans Camdida albicans is opportunistic organism : Fungi are harmless , because they are saprophytic It’s present normally in the body, but once the immunity get which feed on dead things instead of living plants weaker or lower , it multiply and grow a disease or animals Morphological classification of fungi: 1-Yeasts: Yeasts grow as single cells that reproduce by budding. ‫تبرعم‬ - 99.  Multiple hyphae form mycelium 2- Moulds: Molds grow as long filaments (hyphae) and form a mycelium. Some hyphae form transverse walls (septate hyphae), whereas others do not (non-septate hyphae). Septa : ‫حواجز‬ Non- Septa : ‫بدون حواجز‬ 3-Several medically important fungi are dimorphic: two morphologies depending on the temperature They exist as molds in the environment at 25 c. Yeasts in human tissues at body temperature 37 c. CLASSIFICATION Doctor said : just the first example of each Most important and common Fungi is Dimorphic The most Fungi that produce human infection are dimorphic  Clinical classification: Fungal Infections (Mycoticinfections): that classified according to the layer of skin affected into: Superficial mycoses: affect the keratinized part of the skin. Hair/ Nails Cutaneous mycoses: affect deep layer of the skin Subcutaneous mycoses: affect the subcutaneous layer of the skin during trauma The most common Deep(systemic)mycoses: affect internal organ, in immunocompromised patient. Fungal allergy: occurs by the spores of fungi causing asthma or urticarial. Mycotoxicosis: that produced by potent toxins produced as aflatoxin. Very toxic to liver cells The most famous toxic produced by the Fungi is : Aflatoxin  Immune mechanism against fungi Acute suppuration, characterized by the presence of neutrophilsin the exudate. The response to infection with many fungi is the formation of granulomas. It is a cell-mediated immune response. Activation of the cell-mediated immune system results in a delayed hypersensitivity skin test response to certain fungal antigens injected intradermally. Innate immunity , Neutrophils are the most important cell involved against fungal infection. Aquired immunity , the most important response is the cell- mediated immunity  Laboratory diagnosis of fungal infections · ↑ (1) Direct: microscopic examination, (2) Culture of the organism, Sabouraud agar (3) DNA probe tests. The specimen is very important Treated with 10% potassium hydroxide (KOH) to dissolve tissue material, leaving the alkali-resistant fungi intact. keratin, chitin, and other organic tissues  Culture The culture of fungi will be either on Sabouraud Agar or Sabouraud Dextrose Agar Fungi are frequently cultured on Sabouraud agar, which facilitates the appearance of fungi by inhibiting the growth of bacteria in the specimen. Sabouraud Agar typically has a lower pH (around 5.6), which is more favorable for fungal growth and less so for most bacteria.This helps to reduce bacterial competition, allowing fungi to be more easily observed and isolated in culture.  References Review of Medical Microbiology and Immunology. Warren Levinson , Thirteenth Edition. Jawetkand Melnick& Aldelberges, 26th Edition Medical Microbiology, Lippincott’s Illustrated Reviews: Microbiology, Second Edition. THANK YOU  team Wishes you the best