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Mechanisms of Disease 1 HC12: Introduction to infectious diseases
HC12: Introduction to infectious diseases
The earth's history
Bacteria form an essential part in the development of higher organisms:
- 4 billion years ago: the first bacteria (prokaryotes)
- 2,5 billion years ago: the first 1-cellular organisms (eukaryotes)
- 1,5 billion years ago: the first multicellular eukaryotes
- 0,5 billion years ago: the first fish
If the age of the earth was 1 year, bacteria would've come in February and humans only would have existed in the last minute of December 31st.
Determination of bacteria
Bacteria can be classified based on the structure of the cell wall
- No cell wall → mycoplasma
- Gram-negative → escherichia coli
- Gram-positive → streptococcus pyogenes
- Acid-fast → mycobacterium tuberculosis
Gram negative and positive bacteria can be distinguished with gram stains:
- Gram-negative
- Curved → vibrio campylobacter
- Rods → escherichia and salmonella
- Cocci → neisseria
- Spherical
- Gram-positive
- Rods
- Spore forming → clostridium
- Non spore forming
- Cocci
- Groups → staphylococci
- Chains → streptococci
- Rods
Interaction
Virulence factors describe what the bacterium does with the host (the human). Defense mechanisms describe how the host reacts to the bacterium.
S. pyogenes:
Streptococcus pyogenes is a gram-positive bacteria. They are called extracellular bacteria → cannot survive in a cell. Virulence factors of S. pyogenes are:
- Structural → leads to acute inflammation
- Peptidoglycan
- Lipoteichoic acid
- Products
- Characteristics → acute inflammation
S. pyogenes can enter the body when the barrier function is impaired, for example when the granulocyte function doesn't work due to alcoholism. Defense mechanisms of S. pyogenes are made up of the innate immune system.
Laboratory tests
There are 2 blood tests which can be used to test for inflammation:
- C-reactive protein (CRP)
- Acute phase protein
- There are lots of cytokines → liver responds by exciting lots of proteins (also CRP) → acute phase response
- Rises within hours
- Disappears in days
- Acute phase protein
- Erythrocyte sedimentation rate (ESR)
- Measure of the amount of proteins in the blood
- When there are a lot of proteins, they glue together as "stacks"
- Many proteins can do this
- When there are a lot of proteins, they glue together as "stacks"
- Dependent on the concentration of plasma proteins versus red blood cells
- Fibrinogen
- Immunoglobulins
- Nonspecific
- Rises and disappears more slowly
- Measure of the amount of proteins in the blood
Both are blood tests that aren't specific for a specific bacterium. CRP is an acute marker, ESR is a chronic marker.
Entamoeba histolytica
Entamoeba histolytica is a human pathogen. It lives in the bowel, where it may make a person ill. It is excreted with the feces in 2 forms:
- Cyst form: survives in the environment → bacteria in this form can be transmitted to other humans
Trophozoites: doesn't survive in the environment → dies within seconds/minutes
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This content is used in:
Mechanisms of Disease 1 2020/2021 UL
- Mechanisms of Disease 1 HC1: Introduction to G2MD1
- Mechanisms of Disease 1 HC2: Introduction to the immune system
- Mechanisms of Disease 1 HC3: Innate and adaptive immune responses & key cytokines
- Mechanisms of Disease 1 HC4: Pathology of normal immune response
- Mechanisms of Disease 1 HC5: B- and T-cell generation and diversity
- Mechanisms of Disease 1 HC6: Mechanisms of adaptive immunity
- Mechanisms of Disease 1 HC7: Effector mechanisms of antibodies
- Mechanisms of Disease 1 HC8: B-cell development and antibodies
- Mechanisms of Disease 1 HC9: Tissue injury and repair
- Mechanisms of Disease 1 HC10: Repair mechanism
- Mechanisms of Disease 1 HC11: Pathology of inflammatory reactions
- Mechanisms of Disease 1 HC12: Introduction to infectious diseases
- Mechanisms of Disease 1 HC13: Bacteria
- Mechanisms of Disease 1 HC14: Viruses
- Mechanisms of Disease 1 HC15: Fungi and parasites
- Mechanisms of Disease 1 HC16: Invaders
- Mechanisms of Disease 1 HC17: Host versus invader
- Mechanisms of Disease 1 HC18: Immune deficiencies and infection risk
- Mechanisms of Disease 1 HC19: Pathology of infectious diseases
- Mechanisms of Disease 1 HC20: Diagnostics of infectious diseases
- Mechanisms of Disease 1 HC21: Essential microorganisms
- Mechanisms of Disease 1 HC extra: Mycobacterial infections (tuberculosis)
- Mechanisms of Disease 1 HC22: Antimicrobial therapy
- Mechanisms of Disease 1 HC23: Principles of antibiotic pharmacotherapy
- Mechanisms of Disease 1 HC24: Introduction MOOC
- Mechanisms of Disease 1 HC25: Epidemiology
- Mechanisms of Disease 1 HC26: Prevention and control
- Mechanisms of Disease 1 HC extra: COVID-19
- Mechanisms of Disease 1 HC27: Mechanisms of hypersensitivity reactions
- Mechanisms of disease 1 HC28: Pathology of allergy
- Mechanisms of Disease 1 HC29: Asthma
- Mechanisms of Disease 1 HC30: Pathology of autoimmunity
- Mechanisms of Disease 1 HC31: HLA and autoimmunity
- Mechanisms of Disease 1 HC32: Vasculitis
- Mechanisms of Disease 1 HC33: Systemic Lupus Erythematosus
- Mechanisms of Disease 1 HC35: Infections and autoimmunity
- Mechanisms of Disease 1 HC36: Immune cells in rheumatoid arthritis
- Mechanisms of Disease 1 HC37+38: Pharmacology: immunosuppression
- Mechanisms of Disease 1 HC39: Pathology of transplantation
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Mechanisms of Disease 1 2020/2021 UL
Deze bundel bevat aantekeningen van alle hoorcolleges van het blok Mechanisms of Disease 1 van de studie Geneeskunde aan de Universiteit Leiden, collegejaar 2020/2021.
This bundle contains notes of all lectures from the module Mechanisms of Disease 1, Medicine, Leiden
...- Lees verder over Mechanisms of Disease 1 2020/2021 UL
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