医学微生物-细菌生理和消毒灭菌课件

1、Chapter2 Bacterial Physiology,outline,Physical and Chemical Properties Growth and Proliferation Metabolism Cultivation Method Classification and Nomenclature,I Physical and Chemical Properties,Chemical composition Water, inorganic salts, proteins, carbohydrates, lipids, nucleic acids Macronutrients(macroelements) Carbon, oxygen, hydrogen, nitrogen, sulfur, phosphorus and other metal ions (potassium, calcium, magnesium and iron) The first six(C, O, H, N, S, and P) are components of carbohydrates,

2、 lipids, proteins, and nucleic acids. Micronutrients(trace elements),Physical properties Optical property Surface area Charged phenomena Semi-permeability Osmotic pressure,II Growth and Proliferation,Bacterial requirements for growth Nutrients pH Temperature Oxygen Osmotic pressure (Optimal environmental condition),Nutrients,Nutrient Requirements Carbon sources Nitrogen sources Inorganic salts and trace elements Growth factors Water,Nutritional types of bacteria Autotroph reduced inorganic molec

3、ules Heterotroph organic molecules saprophyte parasite,Uptake of nutrients by bacteria Passive diffusion simple diffusion Facilitated diffusion Active transport,pH,Many bacteria grow best at neutral pH. (pH 7.2-7.6) Some specialized bacteria can survive and even grow in acid or alkaline conditions. T.B. pH 6.5-6.8 V. cholerae pH 8.4-9.2,Temperature and Growth,Temperature,Heat-shock proteins, Hsp,Temperature ranges for microbial growth,Oxygen Requirements,Obligate aerobes Must grow in the presenc

4、e of air They can not carry out fermentation Microaerophilic bacterium Grow well in low concentrations of oxygen Killed by higher concentrations of oxygen Facultative anaerobe Perform both fermentation and aerobic respiration Can survive in the presence of oxygen Obligate anaerobe,Obligate anaerobes Do not carry out oxidative phosphorylation Killed by air Lack certain enzymes cytochrome and cytochrome oxidace superoxide dismutase (SOD) O2- + 2H+ to H2O2 catalase 2H2O2 to 2H2O + O2 peroxidase H2O

5、2 to H2O using NAD to NADH,Growth and multiplication,Generation time: the time required for bacterial mass to double. 20-30min, T.B. 18-20h,mode: Binary fission,The growth curve,Phases of Microbial Death Curve,CO2 Osmotic pressure,III Metabolism,Energy metabolism of bacteria Catabolism anabolism Respiration Fermentation,Metabolic products of bacteria Catabolism and biochemical reaction Sugar fermentation IMViC Indole Methyl red VP Citrate utilization H2S Urease,Anabolic products of bacteria Pyro

6、gen Toxin and invasive enzyme (endotoxin, exotoxin) Pigment Antibiotics Bacteriocin Vitamins,IV Cultivation Method,Environmental factors affecting growth Nutrients; pH; Temperature; Aeration ; Ionic strength; Osmotic pressure Basic medium 0.3% 牛肉膏 1% 蛋白胨 0.5% NaCl,Liquid medium,(1-2% agar) Solid medium (0.3-0.5% agar) Semi-solid medium,Growth of bacteria in culture medium Liquid medium or Broth Homogeneous turbidity Surface Bottom Solid agar medium Colony and mossy Smooth colony Rough colony Muc

7、oid colony Semi-solid agar medium,Types of Culture medium basic medium nutrient medium selective medium differential medium anaerobic medium,Usage of bacterial culture Diagnosis, prevention and treatment of infection diseases Characterization of bacteria Preparation of vaccines, toxoids and other biologic prducts Application in industry and agriculture Uses for genetic engineering,V Classification and nomenclature,Taxonomic ranks,Family：a group of related genera. Genus：group of related species.

8、Species: a group of related strains. Type: sets of strain within a species serotype Phage-type biotype genotype Strain: one line or a single isolate of a particular species.,Bionomial Nomenclature: genus+species,Chapter3 Disinfection and sterilization,outline,Definition Physical methods Chemical methods,Disinfection Sterilization Antisepsis Asepsis, asepsis technique,I Definition,Disinfection killing, or removal of microorganisms that may cause disease. primary goal is to destroy potential patho

9、gens.,Sterilization all living cells, viable spores, viruses, and viroids are either destroyed or removed from an object or habitat. totally free of viable microorganisms, spores, and other infectious agents.,Antisepsis prevention of sepsis and is accomplished with antiseptics. Asepsis without living microorganisms,Methods for control of microorganisms,Physical methods Heat Hot-air sterilizer Autoclaving Radiation Filtration Ultrasound Dryness Low temperature Chemical agents,II physical methods,Heat Dry heat Incineration Direct flames Hot-air sterilizer 160-170C for 2 hours-spores Glass petri dishes and pipettes Infrared microwave,Moist heat Pasteuriztion 63C for 30min Flash pasteuriztion - 72C for 15s Ultrahigh-temperature(UHT) sterilization-140 to 150C for 1 to 3s Boiling Free-flowing steam disinfection Autoclaving 15 pounds(1.05kg/cm2), 121C for 15-20min,Radiation Ultraviolet, UV 250-260nm Quite lethal but does not penetrate glass, dirt films, water, and

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