微生物学美国IndianaUniversityPurdueUniversity授课05
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微生物学美国IndianaUniversityPurdueUniversity授课12
– Some are always associated with disease
• e.g., Shigella, Salmonella, Yersinia pestis
– Some are normal flora that can become opportunistic pathogens
• e.g., E. coli, K. pneumoniae, P. mirabilis
• Infants< 1 year affected
– Enterohemorrhagic (EHEC; hemorrhagic colitis)
• Produces cytotoxin (verotoxin) • Severe abdominal pain, bloody diarrhea, little or no
• Can involve all body sites • 5% hospitalized patients develop nosocomial
infections, primarily caused by Enterobacteriaceae
such as Escherichia
• Sites of infection
BIOL 533
7
Lecture 12
Virulence Factors
• Capsular K
– Either protein or polysaccharide
• Heat-labile • May interfere with detection of “O” • Removed by boiling organisms
• Cross reactions
– E. coli K1 with N. meningitidis and Haemophilus meningitidis
微生物学美国IndianaUniversityPurdueUniversity授课03
(see Nester 10.13—Colony Hybridization)
– Bordetella pertussis
• Intracranial • Interperitoneal • Respiratory aspiration
BIOL 533
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Lecture Three
Choosing an Animal Model
• Ideally, want model to:
BIOL 533
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Lecture Three
Immunological
• Determine whether Ab to bacterial product are protective in infected animals
• Possible problem:
– Ab to bacterial surface molecules might prevent infection by opsonizing or enhancing complement action rather than inactivating virulence factor
– S. typhimurium is pathogen and normal E. coli is not; therefore, the differing
sequences may be virulence genes
BIOL 533
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Lecture Three
Wild Type
• Experimental technique:
– Measurements on isolated molecules may not accurately reflect function in intact bacterium
– Bordetella pertussis
• Intracranial • Interperitoneal • Respiratory aspiration
BIOL 533
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Lecture Three
Choosing an Animal Model
• Ideally, want model to:
BIOL 533
10
Lecture Three
Immunological
• Determine whether Ab to bacterial product are protective in infected animals
• Possible problem:
– Ab to bacterial surface molecules might prevent infection by opsonizing or enhancing complement action rather than inactivating virulence factor
– S. typhimurium is pathogen and normal E. coli is not; therefore, the differing
sequences may be virulence genes
BIOL 533
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Lecture Three
Wild Type
• Experimental technique:
– Measurements on isolated molecules may not accurately reflect function in intact bacterium
微生物学美国IndianaUniversityPurdueUniversity授课14
cellular immunity are at increased risk
BIOL 533
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Lecture 14
Laboratory Diagnosis
• Microscopy
– Difficult because of
• lack of staining • intracellular nature • Require large number of organisms to detect
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Lecture 14
History
• Six months after outbreak, CDC isolated bacteria from post-mortum lung tissue
– Inoculated lung tissue into peritoneal cavity of guinea pigs
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Lecture 14
Microbial Physiology and Structure
• Family Legionellaceae
• One genus: Legionella
– 25 species and 42 serotypes
– Legionella pneumophila responsible for 85%
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Lecture 14
Disease Syndromes
• Legionaire’s disease
– Much more severe, with high mortality unless promptly treated
• Overall mortality is 15-20% • Symptoms reviewed in Pathogenesis section
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Lecture 14
Laboratory Diagnosis
• Microscopy
– Difficult because of
• lack of staining • intracellular nature • Require large number of organisms to detect
BIOL 533
2
Lecture 14
History
• Six months after outbreak, CDC isolated bacteria from post-mortum lung tissue
– Inoculated lung tissue into peritoneal cavity of guinea pigs
BIOL 533
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Lecture 14
Microbial Physiology and Structure
• Family Legionellaceae
• One genus: Legionella
– 25 species and 42 serotypes
– Legionella pneumophila responsible for 85%
BIOL 533
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Lecture 14
Disease Syndromes
• Legionaire’s disease
– Much more severe, with high mortality unless promptly treated
• Overall mortality is 15-20% • Symptoms reviewed in Pathogenesis section
微生物学美国IndianaUniversityPurdueUniversity授课01
– Typhus and Black Plague epidemics: only half of population became sick, even though most likely exposed
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Lecture One
Host-Parasite Interaction
• No term for urinary or genital entry
• By bypassing epithelial tissue, microbes can cause disease without penetrating deep into tissues
– Cholera, whooping cough, infection of urinary bladder
2
Lecture One
Characteristics of Parasitism
• Encounter: agent meets host • Entry: agent enters host • Spread: agent spreads • Multiplication: agent multiplies • Damage: agent, host response, or both
BIOL 533
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Lecture One
Digestive System
• More survive in ileum, but need mechanisms to prevent expulsion
– Surface components serve as adhesins to allow adherence to epithelial cells
BIOL 533
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Lecture One
Host-Parasite Interaction
• No term for urinary or genital entry
• By bypassing epithelial tissue, microbes can cause disease without penetrating deep into tissues
– Cholera, whooping cough, infection of urinary bladder
2
Lecture One
Characteristics of Parasitism
• Encounter: agent meets host • Entry: agent enters host • Spread: agent spreads • Multiplication: agent multiplies • Damage: agent, host response, or both
BIOL 533
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Lecture One
Digestive System
• More survive in ileum, but need mechanisms to prevent expulsion
– Surface components serve as adhesins to allow adherence to epithelial cells
2023印第安纳大学微生物学与免疫学专业详细介绍
2023印第安纳大学微生物学与免疫学专业详细介绍1500字印第安纳大学微生物学与免疫学专业是该校生命科学学院下属的一个专业，该专业旨在培养学生在微生物学和免疫学领域具有扎实的理论基础和实践能力的专业人才。
该专业的课程设置广泛涵盖了微生物学、免疫学、分子生物学、遗传学、生物化学等相关学科，并注重培养学生的实验操作和科研能力。
该专业的课程设置主要包括以下几个方面：1. 微生物学基础：这门课程介绍了微生物的分类、特征、生长特性、代谢途径以及与人类和环境的相互作用。
学生将学习微生物的培养、观察和实验操作技能，并了解微生物在生态系统中的重要性。
2. 免疫学基础：这门课程介绍了免疫系统的结构、功能和调节机制，以及与免疫系统相关的疾病和治疗方法。
学生将学习免疫系统的免疫细胞、抗体和免疫反应的基本原理，并掌握免疫实验技术。
3. 分子生物学和遗传学：这门课程介绍了基因的结构和功能，基因表达调控机制以及分子生物学实验技术。
学生将学习基因克隆、DNA测序、PCR等技术，并了解基因的突变和遗传疾病的机制。
4. 生物化学：这门课程介绍了生物大分子的结构和功能，代谢途径，生物催化等基础知识。
学生将学习蛋白质结构与功能、酶学等内容，并了解生物化学研究的方法和应用。
除了以上的基础课程，学生还可以选择一些专业选修课程来进一步深入学习微生物学与免疫学领域的特定知识。
比如：1. 微生物遗传学：这门课程介绍了微生物的基因组、遗传变异和基因调控机制。
学生将学习微生物基因组学研究方法和应用，了解微生物遗传多样性的形成和演化。
2. 免疫学实验技术：这门课程重点讲解免疫实验技术，包括细胞培养、免疫印迹、流式细胞术等常用实验技术的原理和操作方法。
学生将通过实验操作掌握免疫学实验技术的基本操作和数据分析能力。
3. 微生物流行病学：这门课程介绍了微生物流行病学的基本概念、研究方法和应用。
学生将学习流行病学的调查设计、数据分析和预防控制措施，了解微生物在人群中的传播规律和预防策略。
微生物学美国IndianaUniversityPurdueUniversity授课10
BIOL 533
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Lecture 10
Virulence Factors of S. aureus
• Stage IV, continued
– Secretion of toxins
• Enterotoxins (A-E)—found in both S. aureus and S. epidermidis
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Lecture 10
Pathogenesis of S. aureus
• Stage I: encounter—humans are major
reservoir for S. aureus
– Colonize nose and are found in about 30% of individuals
• Acute inflammatory reaction
– Proportion of bacteria survive and are capable of lysing neutrophils that engulfed them » Outpouring of lysosomal enzymes that damage surrounding tissues
• Coagulase—makes fibrin clot (wbc penetrate
badly; only S. aureus)
• Hylauronidase—degrades connective tissues
(facilitates spread; 90% of S. aureus strains)
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Lecture 10
Staphylococci
微生物学美国IndianaUniversityPurdueUniversity授课02
– Serve as defense mechanism even in low concentration
– Bacterial stimulation leads to production of IgA that is secreted through mucus membranes
• Probably interfere with colonization of deeper tissues
• Lupus erythematosus—production of Ab against host DNA
– Some evidence that Ag may be cross-reacting bacterial LPS
• May cross-react with pathogen (meningococcus)
– Example: about 10% of population have meningococcus or pneumococcus as normal flora
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Lecture Two
Importance
• Opportunistic infections: normal flora in unusual sites; for example:
– Both endogenous and exogenous organisms can cause disease
• Infecting dose of Salmonella decreases one
million-fold when mice given streptomycin
• Patients treated with some potent antibiotics:
– Bacterial stimulation leads to production of IgA that is secreted through mucus membranes
• Probably interfere with colonization of deeper tissues
• Lupus erythematosus—production of Ab against host DNA
– Some evidence that Ag may be cross-reacting bacterial LPS
• May cross-react with pathogen (meningococcus)
– Example: about 10% of population have meningococcus or pneumococcus as normal flora
BIOL 533
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Lecture Two
Importance
• Opportunistic infections: normal flora in unusual sites; for example:
– Both endogenous and exogenous organisms can cause disease
• Infecting dose of Salmonella decreases one
million-fold when mice given streptomycin
• Patients treated with some potent antibiotics:
微生物学美国IndianaUniversityPurdueUniversity授课04
BIOL 533
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Lecture 4
Analysis of Virulence
• Expression problem may explain why 9/15 Pho+ avirulent mutant strains were LPS— rather than being defective in other virulence genes
BIOL 533
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Lecture 4
Analysis of Virulence
• TnphoA narrows, but doesn’t solve all
detection problems
– While disrupting gene, the TnphoA mutations
produce alkaline phosphatase hybrid proteins
• Can also be cloned by complementation
• Cloned DNA can be sequenced
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Lecture 4
phoA Gene Fusions
• Virulence genes are small subset of total genes, so random mutagenesis will affect many more non-virulence genes
– Two coding sequences must be in frame
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Lecture 4
Technique
• Use transposon vector containing lac
微生物学美国IndianaUniversityPurdueUniversity授课08
Prevent Complement Activation
• Cost of having capsule— antigenic
– Elicits activation by primary pathway
• Defend better against immediate defenses than later ones
• Tuberculosis • Psittacosis • Legionnaire’s disease
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Lecture 8
Subversion of Phagocytosis
– Mechanism of tuberculosis
• Induced by complex glycolipids (sulfatides)—not certain
– Since lysosomes do not secrete contents into cytoplasm, organism is safe
– How they enter cytoplasm is not known for certain » Possess surface-bound phospholipase, which may weaken membrane
– Correlates with pathogenicity
BIOL 533
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Lecture 8
Subversion of Phagocytosis
• Overall strategies
– Inhibition of phagocyte recruitment
– Microbial killing of phagocytes
微生物学美国IndianaUniversityPurdueUniversity授课12
BIOL 533
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Lecture 12
Virulence Factors
• Capsular K
– Either protein or polysaccharide
• Heat-labile • May interfere with detection of “O” • Removed by boiling organisms
flora in this group
• Eosin Methylene Blue (EMB)
– Lactose, eosinY, methylene blue; Lac+; grow with green sheen
BIOL 533
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Lecture 12
Virulence Factors
• Antigens
• Role that Ag’s play in these diseases is not clear
– Some capsular Ag are poor immunogens
• Protect against antibody-mediated phagocytosis
– Flagellar Ag probably play a role in adherence
– Adhesiveness mediated by plasmid-encoded pili
BIOL 533
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Lecture 12
Pathogenesis of Escherichia
• Gastroenteritis, continued
– Enteropathogenic (continued)
• Oxidase¯:
微生物学美国IndianaUniversityPurdueUniversity授课08培训资料
by capsule
• Capsules rich in sialic acid of Group B streptococci
and strains of E. coli
BIOL 533
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Lecture 8
Prevent Complement Activation
– IgA antibodies
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Lecture 8
General Aspects
• Pathogen finds itself in hostile territory
– Host fights back and usually—but not always—wins
• Host’s defenses are interrelated and so are organism’s countermeasures
• Have to determine precise role of each factor if a large number are involved
– Not always sure in vitro situation is same as in
disease state
BIOL 533
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» Cannot act as opsonins because Fc region not free to bind to Fc receptors on phagocytic cells
» Not known if antiphagocytic defense is relevant to disease process
BIOL 533
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Lecture 8
General Aspects
• Capsules rich in sialic acid of Group B streptococci
and strains of E. coli
BIOL 533
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Lecture 8
Prevent Complement Activation
– IgA antibodies
BIOL 533
2
Lecture 8
General Aspects
• Pathogen finds itself in hostile territory
– Host fights back and usually—but not always—wins
• Host’s defenses are interrelated and so are organism’s countermeasures
• Have to determine precise role of each factor if a large number are involved
– Not always sure in vitro situation is same as in
disease state
BIOL 533
4
» Cannot act as opsonins because Fc region not free to bind to Fc receptors on phagocytic cells
» Not known if antiphagocytic defense is relevant to disease process
BIOL 533
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Lecture 8
General Aspects
微生物学美国IndianaUniversityPurdueUniversity授课03
BIOL 533
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Lecture Three
Wild Type
• Sequence wild-type or mutated gene:
– Sometimes find unexpected relationships
– Useful only if match known gene sequence
– Use same route as human disease – Display same symptoms – Display same virulence
• Alternative: cell culture, organ culture
BIOL 533
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Lecture Three
Cell Culture/Organ Culture
– S. typhimurium is pathogen and normal E. coli is not; therefore, the differing
sequences may be virulence genes
BIOL 533
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Lecture Three
Wild Type
• Experimental technique:
Medical Microbiology
Strategies for Studying Microbial Pathogenesis
BIOL 533 Lecture 3
BIOL 533
1
Lecture Three
Choosing an Animal Model
• Pathogen may not affect animal at all
BIOL 533
微生物学美国IndianaUniversityPurdueUniversity授课06
two-week period
• Production of granules during this time
– Azurophil – Produce specific granules later
BIOL 533
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Lecture 6
Phagocytes—Types of Cells
• Neutrophils—cell origin, continued
– Upon maturation (in numbers of 1010 per day), they move into peripheral blood and circulate for about 6.5 hours
– Next move into capillary bed and marginate
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Lecture 6
Mechanism of Phagocyte Killing
• Neutrophils
– General steps
• Attach to microbes • Ingest microbes • Kill microbes
– Granules—considered as enlarged lysosomes containing hydrolytic enzymes
• Monocytes and macrophage
– Compared to neutrophils
• Arrive at damaged tissue later in infection
– Days after neutrophils have been active in fighting intruders
• Production of granules during this time
– Azurophil – Produce specific granules later
BIOL 533
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Lecture 6
Phagocytes—Types of Cells
• Neutrophils—cell origin, continued
– Upon maturation (in numbers of 1010 per day), they move into peripheral blood and circulate for about 6.5 hours
– Next move into capillary bed and marginate
BIOL 533
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Lecture 6
Mechanism of Phagocyte Killing
• Neutrophils
– General steps
• Attach to microbes • Ingest microbes • Kill microbes
– Granules—considered as enlarged lysosomes containing hydrolytic enzymes
• Monocytes and macrophage
– Compared to neutrophils
• Arrive at damaged tissue later in infection
– Days after neutrophils have been active in fighting intruders
微生物学美国IndianaUniversityPurdueUniversity授课14
phagocyte
BIOL 533
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Lecture 14
Damage
• Organism possesses several exotoxins
– Proteases, hemolysins, and other cytotoxins
• One inhibits oxidative killing of neutrophils • May also damage tissue directly
BIOL 533
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Lecture 14
Microbial Physiology and Structure
• Morphology
– Gram— rods (pleomorphic on artificial media)
• Do not stain well except with special silver stain
• Some patients have gastrointestinal symptoms, including diarrhea
BIOL 533
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Lecture 14
Disease Syndromes
• In general, healthy people rarely get disease
Legionella pneumophila
– Epidemiological search revealed outbreak in same hotel two years earlier
• Culture problems because organisms:
– Do not grow on common laboratory media – Do not readily stain
BIOL 533
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Lecture 14
Damage
• Organism possesses several exotoxins
– Proteases, hemolysins, and other cytotoxins
• One inhibits oxidative killing of neutrophils • May also damage tissue directly
BIOL 533
6
Lecture 14
Microbial Physiology and Structure
• Morphology
– Gram— rods (pleomorphic on artificial media)
• Do not stain well except with special silver stain
• Some patients have gastrointestinal symptoms, including diarrhea
BIOL 533
13
Lecture 14
Disease Syndromes
• In general, healthy people rarely get disease
Legionella pneumophila
– Epidemiological search revealed outbreak in same hotel two years earlier
• Culture problems because organisms:
– Do not grow on common laboratory media – Do not readily stain
微生物学美国IndianaUniversityPurdueUniversity授课04学习资料
BIOL 533
15
Lecture 4
Analysis of Virulence
• Disadvantage:
– Limits selection to genes expressed in
S. typhimurium on L-agar
– Genes expressed at low levels or repressed on L-agar plates would be missed
• Initiation signal/+NH2 coding sequence
– Translational signal also from reporter gene
• Initiation sequence and part of NH2 sequence of reporter gene missing, but COOH region still present
antibiotic marker
– Selection for antibiotic marker generates set of random insertions in chromosome
– Colonies carrying transposon screened for expression under conditions tested
BIOL 533
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Lecture 4
TnphoA Transposon
• Use TnphoA:
– Study topology of inner membrane proteins
• βgal fusions expressed only in cytoplasm
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– By injury – By infecting microbes – By inflammatory response
BIOL 533
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Lecture 5
Inflammation
• Description of changes
– Blood supply increases to affected part due to vasodilation
BIOL 533
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Lecture 5
Lecture 5
Lecture 5
Defenses of Deep Tissues
• Role of constitutive defenses, cont’d.
– Inflammatory response does not require previous contact with microorganism
– Tissues may return to normal or scarring may result
BIOL 533
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Lecture 5
Inflammation
• Tissues may return to normal or scarring may result; depends on extent of damage done:
– Histamine
– Kinin
– Leukotrienes and prostaglandins
BIOL 533
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Lecture 5
Molecular Basis
• Histamine is one of best-known
– Dilates blood vessels and increases permeability
– Elicited by complex effectors, many of which are complement system
• Normally at basal level and must be further increased by presence of microorganisms in tissues
• Complement and clotting are interactive • Either can set off the other • Normally, clotting is seen when acute inflammatory
response is severe
BIOL 533
– Inducible response cannot occur without constitutive mediators
• Mediators lead to induction of immune response and also defend against microbial invader
Medical Microbiology
Constitutive Defenses of the Host
BIOL 533 Lecture 5
BIOL 533
1
Lecture 5
Constitutive Defenses
• Barriers to entry
– See Schaechter text, Table 6.1
– Most important consequence of activity is phagocyte attraction
BIOL 533
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Lecture 5
Defenses of Deep Tissues
• Interaction of constitutive (inflammatory response) and inducible defenses (immune response)
10
Lecture 5
Molecular Basis
• Inflammatory response leads to production and release of a number of chemical effectors of inflammation responsible for vascular permeability, vasodilation, and pain
• Mucous membranes—covered by protective layer of mucus
– Mechanical and chemical barrier that allows proper functioning
• Cross-linked gel structure composed of glycoprotein subunits
– Production of lactic acid—antimicrobial
BIOL 533
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Lecture 5
Inflammation
• Molecular basis of inflammatory response and acute phase response
– Inflammatory response starts with activation of complement or of blood-clotting cascade
– Capillaries become more permeablo move into tissues
– Consequence of inflammation
• pH of inflamed tissues lowered
BIOL 533
6
Lecture 5
Inflammation
• General aspects
– Reaction to tissue injury—manifested by pain, swelling, heat, and throbbing of location
– Location appears red and shiny, hot and painful to touch as a result of changes in local blood vessels and lymphatics
BIOL 533
8
Lecture 5
Inflammation
• Description of changes
– Blood supply increases to affected part due to vasodilation
BIOL 533
2
Lecture 5
Lecture 5
Lecture 5
Defenses of Deep Tissues
• Role of constitutive defenses, cont’d.
– Inflammatory response does not require previous contact with microorganism
– Tissues may return to normal or scarring may result
BIOL 533
7
Lecture 5
Inflammation
• Tissues may return to normal or scarring may result; depends on extent of damage done:
– Histamine
– Kinin
– Leukotrienes and prostaglandins
BIOL 533
11
Lecture 5
Molecular Basis
• Histamine is one of best-known
– Dilates blood vessels and increases permeability
– Elicited by complex effectors, many of which are complement system
• Normally at basal level and must be further increased by presence of microorganisms in tissues
• Complement and clotting are interactive • Either can set off the other • Normally, clotting is seen when acute inflammatory
response is severe
BIOL 533
– Inducible response cannot occur without constitutive mediators
• Mediators lead to induction of immune response and also defend against microbial invader
Medical Microbiology
Constitutive Defenses of the Host
BIOL 533 Lecture 5
BIOL 533
1
Lecture 5
Constitutive Defenses
• Barriers to entry
– See Schaechter text, Table 6.1
– Most important consequence of activity is phagocyte attraction
BIOL 533
5
Lecture 5
Defenses of Deep Tissues
• Interaction of constitutive (inflammatory response) and inducible defenses (immune response)
10
Lecture 5
Molecular Basis
• Inflammatory response leads to production and release of a number of chemical effectors of inflammation responsible for vascular permeability, vasodilation, and pain
• Mucous membranes—covered by protective layer of mucus
– Mechanical and chemical barrier that allows proper functioning
• Cross-linked gel structure composed of glycoprotein subunits
– Production of lactic acid—antimicrobial
BIOL 533
9
Lecture 5
Inflammation
• Molecular basis of inflammatory response and acute phase response
– Inflammatory response starts with activation of complement or of blood-clotting cascade
– Capillaries become more permeablo move into tissues
– Consequence of inflammation
• pH of inflamed tissues lowered
BIOL 533
6
Lecture 5
Inflammation
• General aspects
– Reaction to tissue injury—manifested by pain, swelling, heat, and throbbing of location
– Location appears red and shiny, hot and painful to touch as a result of changes in local blood vessels and lymphatics