tailieunhanh - Ebook Sherris medical microbiology (6th edition): Part 2

(BQ) Part 2 book "Sherris medical microbiology" presentation of content: Fungi—Basic concepts, pathogenesis and diagnosis of fungal infection, antifungal agents and resistance, pathogenesis and diagnosis of parasitic infection, intestinal nematodes, tissue nematodes, cestodes, trematodes,. and other contents. | PART Pathogenic Fungi IV Kenneth J. Ryan Fungi—Basic Concepts CHAPTER 42 Pathogenesis and Diagnosis of Fungal Infection CHAPTER 43 Antifungal Agents and Resistance CHAPTER 44 Dermatophytes, Sporothrix, and Other Superficial and Subcutaneous Fungi CHAPTER 45 Candida, Aspergillus, Pneumocystis, and Other Opportunistic Fungi CHAPTER 46 Cryptococcus, Histoplasma, Coccidioides, and Other Systemic Fungal Pathogens CHAPTER 47 This page intentionally left blank Chapter 42 1 Fungi—Basic Concepts F ungi or the Eumycota are a distinct class of microorganisms, most of which are freeliving in nature where they function as decomposers in the energy cycle. Of the more than 90 000 known species, fewer than 200 have been reported to produce disease in humans. These diseases have unique clinical and microbiologic features and are increasing in immunocompromised patients. MYCOLOGY Fungi are eukaryotes with a higher level of biologic complexity than bacteria. They are spore bearing; reproducing both sexually and asexually. Fungi may be unicellular or may differentiate and become multicellular by the development of long-branching filaments. They acquire nutrients by absorption but lack the chlorophyll of plants. The diseases caused by fungi are called mycoses. They vary greatly in their manifestations but tend to be subacute to chronic with indolent, relapsing features. Acute disease, such as that produced by many viruses and bacteria, is uncommon with fungal infections. Cell organization is eukaryotic STRUCTURE The fungal cell has typical eukaryotic features, including a nucleus with a nucleolus, nuclear membrane, and linear chromosomes (Figure 42–1). The cytoplasm contains a cytoskeleton with actin microfilaments and tubulin-containing microtubules. Ribosomes and organelles, such as mitochondria, endoplasmic reticulum, and the Golgi apparatus, are also present. Fungal cells have a rigid cell wall external to the cytoplasmic membrane, which differs in its .