Principles Of Infection I Flashcards
What are microorganisms?
Bacteria, virus, fungi that are too small to be seen by the naked eye
They can exist as a single cell or in a colony of cells
Classifications of microorganisms.
Helminths = Animals Fungi = Fungi Algae = Algae Protozoa = Protozoa Archer = crenachaeota
What is the definition of Infection?
A transmissible, communicable form of disease which is caused by microorganisms (Including Viruses)
What are the five stages of infection?
Incubation Prodromal Illness Decline Convalescence
Give examples of different sub-types of infection
Viral
Fungal
Parasitic
Bacterial
What cell type is a bacterial cell?
Eukaryotic
What type of infection is easier to treat/Kill with antibiotics?
Gram positive
What are the key features of bacterial cells?
There is no nucleus
They have a peptidogyclan cell wall.
Have circular DNA
Lack of membrane bound organelles
What are the two gram stains that can be achieved?
Gram positive
Gram negative
What is the innate immune system?
Non-specific defence system which can act quickly; within minutes and hours
Present from birth
innate immune responses are the first line of defence against invading pathogens.
What are anatomical barriers?
Tough/ intact barriers which prevent entry and colonisation of many microbes
List Examples of anatomical barriers
Skin
Mucous membranes
Bony encasements
What are antimicrobial peptides?
Very small and can kill bacteria directly
What is the first line of defence of all multicellular organisms?
Antimicrobial peptides
What are the different types of white blood cells
Neutrophils Basophils Eosinophils Monocytes Lymphocytes
What is the mechanism of the innate immune system?
Skin
Chemicals in the blood
Immune system. cells attack foreign cells in the body
What is the adaptive immune system?
Highly specialised systems that take longer to produce (time) to produce antigens within the body.
Give some examples of antimicrobial peptides?
Cationic peptides
noncationic peptides
Glycopeptide vancomycin
What are cationic peptides?
Short peptides secreted by the immune/ epithelial cells
What cells are involves in cell mediated response?
T - cells
What cells does the humeral response involve?
Antimicrobial peptides, antibodies
B cells/ antibodies
What are the 2 responses antibodies are involved in?
Primary & secondary response
What does the primary response involve?
Memory cells are low in levels, slower response
What does the secondary response involve?
Memory cells are high in levels
Much faster response
What is human microbiota?
All microorganisms living in and on a human
What is a microbiome?
All genes of all microbiota
List infections caused by bacterial cells.
Cholera
Tuberculosis
Syphilis
Bacterial meningitis
What is the difference between gram negative & gram positive stains
Gram positive keeps the purple stain
Gram negative loses the purple stain (turns pink)
Why does the gram negative cell lose the purple stain?
Due to the presence of the peptidoglycan cell wall
What is the structure of a gram negative cell?
Thin layers of peptidoglycan walls but there are two; outer and inner lipid membranes which makes it harder to penetrate the cell wall
What is the structure of gram positive cell
Thick layer of peptidoglycan wall but there is no outer lipid membrane
Has one inner plasma membrane and this can be penetrated easily by antibiotics
What is easier to kill with antibiotics?
Gram positive
What are the main bacterial shapes?
Cocci - spherical bacteria
Bacilli - rod shaped bacteria
Spirilla - spiral shaped bacteria
Vibrio - curved bacteria
What are the three main types of bacteria in regards to oxygen?
Faculatative anaerobes
Anaerobic organisms
Aerobic organisms
What are the stages of viral reproduction?
Attachment Penetration Uncoating Replication of nucleic acid and synthesis of protein coats Assembly Release
What are the 4 stages of infection?
Transmission
Infection
Pathogenicity
Virulence
What is the transmission stage of infection?
Host acquires the organism
What is the infection stage of infection?
Organism has to reproduce inside the host
What is the pathogenicity stage of infection?
Interacting with the host in a way that causes disease
What is the virulence stage of infection?
This is the severity of the disease
What are the main factors of virulence?
Adhere to and invade host tissues
Evade host defences
Proliferate in the host
Cause damage = produce toxins
What does virulence factors allow to take place?
Enables the host to replicate and spread within a host
How do we evade host defences
Can be achieved by entering the bloodstream
What is the name given to the production of toxins?
Toxigenicity
What is an antigenic drift?
Small changes in viral antigens due to point mutations in genes.
It makes the virus harder for adaptive immune system to recognise.
What is antigenic shift?
Major changes in viral antigens due to gene reassortment.
Makes virus much harder for adaptive immune system to recognise.
How do virulence factors arise?
Encoded and translated for genes in chromosomal DNA
State some infections due to virus.
Flu
Smallpox
Common cold
HIV/AIDS
