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Medical Microbiology
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Medical Microbiology

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  1. Medical Microbiology

  2. 一 concept of microoranism : • 二 type of microorganism: • 1 non-cell type • 2 prokaryotes • 3 eukaryotes • 三 general properties of M: • 1 tiny in size • 2 simple in structure • 3 active in metabolism • 4 fast rate in multiplication • 5 easy in variation • 6 widely distributed

  3. 四 relationship to human • (一)C .N circulation in nature

  4. (二)in industry 、agricuture 、medicine • (三)make up of normal flora of human being • 1 anti-pathogen • 2 provide nutrition • (四)some M are pathogens • 1 pathogens • 2 opportunistic pathogens

  5. 五 history : • leeuwenhoek . 1676 .microscopy • (>200 times )

  6. Pasteur (1822-1895 ) :

  7. 1 yeast cells cause wines sour 2 pebrine caused by protozoan 3 spontaneous generation controversy

  8. 4 chickens: 42℃ , do not acquire anthrax 37℃ ,do 5 vaccine for rabies

  9. koch : (1843—1910)

  10. 1 cultivation techniques 2 staining 3 isolated TB 4 Koch’s postulates :

  11. ①microbes are observed in tissue specimens • from dead animals ; • ②isolated and grown in pure culture ; • ③inoculated to a health animal ; • ④the disease is produced in the animal ; • ⑤then 1 • ⑥then 2

  12. 六 object of medical microbiology • pathogens • 七 why we study medical microbiology • 八 how to study ---:

  13. Chapter 1 . Bacterial • Morphology and Structure

  14. §1 . size and shape of bacteria • size :tiny um (1um=1/1000 mm) • shape : • coccus : diplo~ , strepto~ • tetrad ,sarcina , • staphylo ~ • bacillus : • spiral bacterium :vibrio • spirillum

  15. §2 . structure of bacterium • Structure of Bacteria: • Essential structure: • cell wall • cell membrane • cytoplasm • nuclear material (nucloid) • Special Structure • capsule • flagella • pilus • spore

  16. 一 Essential structure of bacteria • (一)cell wall : • 1 peptidoglycan : • (1) a backbone • (2) tetrapeptide side chains • (3) cross bridges

  17. 2 teichoic acid (G+) (1)membrane ~ (LTA) (2)wall ~

  18. functions : • a. major surface Ag of G+ • b. Regulating passage of ions into and out of G+ • c. binding B onto host cell surface • 3 G- • (1)outer membrane . • (2)LPS • a.lipid A • b.core polysaccharide • c.O-specific polysaccharide

  19. 细胞壁 革兰阳性菌 革兰阴性菌 表1-1 革兰阳性菌与阴性菌细胞壁结构比较 强度 较坚韧 较疏松 厚度 20~80nm 10~15nm 肽聚糖层数 可多达50层 1~2层 肽聚糖含量 占细胞壁干重50%~80% 占细胞壁干重5%~20% 糖类含量 约45% 15%~20% 脂类含量 1%~4% 11%~22% 磷壁酸 + - 外膜 - +

  20. 4 Functions of CW . • (1) to form the external shape of B . • (2) to protect B from bursting due to high • osmolarity :G- 5~6 • G+ 20~25 • (3) A barrier to certain substances into and out of B . • (4) Take part in B multiplication . • (5) Associated with B antigenicity .

  21. 5 B with deficiency in CW (L Forms ) : • Bacterium L-forms : • (B with deficiency in CW ):

  22. 1 pleomorphic • 2 grow in 5% NaCl , 12-15% sucrose . • 3 grow slowly ( 2-7d ) • 4 antibiotics resistant cells . • 5 “fried egg” colony • PC , • 6 G+ , G- ----------- L – form • lysozyme • G+  protoplast • G- spheroplast • 7 Clinic significant

  23. (二)cell membrane . • Functions • (1)  Transportation • (2)Respiration • (3)Biosynthesis • (4)Secretion • Mesosome : • (1)Respiration (chondroid) • (2) Take part in dividing of B

  24. (三)  cytoplasm • 1 Ribosome : • 50S + 30S = 70S • | | • Erythromycin streptomycin • 2 plasmid • 3 cytoplasmic granules • (四) Nuclear material (nucleoid )

  25. 二 special structure of Bacteria • (一)Capsule :

  26. 1 chemical component : • polysaccharide • polypeptide • 2 Functions of capsule : • (1)against phagocytosis • (2)adhesion • (3)protect B from damage. • (against dry) • Glycocalyx

  27. (二)Flagellum :

  28. 1 structure • 2 chemical composition : pro • 3 Function : • (1)Motility • (2)Antigenicity (H – Ag) • (3)Associated with pathogenicity • (4)Differentiation for B

  29. (三)Pilus :

  30. 1 common pilus : pathogenicity • 2 sexpilus :conjugation • F+ →F-

  31. (四)spore :

  32. 1 Formation and Germination • 2 Functions of spore • high resistance • to kill spore:121.3℃ , 15-20min • 1.05kg / cm2 • To kill spore is an important index of autoclaving .

  33. §3 Methods for Identification and Detection of B • 一 microscope magnification • 1 light microscope • 2 electron microscope • 二 staining : (一)Gram stain • Step1 step2 step3 • 1min 1min • Crystal ------ Iodine ----- 95% Alcohol • Violet wash • 30Secstep430Sec • -------- Safranin -------- microscope . • (二)Acid – fast stain .