Commensalism & Pathogenesis Flashcards
How are infections classified
By the causative agent or symptoms
The chain of infection
Susceptible host, causative agent, reservoir, portal Of exit, mode of transmission, portal of entry and back to susceptible host
The causative agent can be a microorganism that is
Endogenous infection which is inside or exogenous infection (outside)
Examples of reservoir in the chain of infection
Environment, animals, humans, soil
Portal of exit examples
Cough/sneeze, sweat, saliva, mucus, vomit, faeces, blood, skin contact, sexual contact, spores, urine, tears, bodily fluids
Portal of exit through the
Nose, mouth, mammory glands, vagina, urethra, ears, eyes, broken skin, skin, anus, seminal vesicles
Mode of transmission examples
Foamities, airborne droplets, direct skin to skin contact/blood, indirect – vectors, contact transmission, droplet, ingestion, inoculation, transplacental
What is foamities
Getting a disease from an object by touch
What is transplacental transmission
From placenta to fetus
Portal of entry examples
Respiratory tract and GI tract
What makes you are more susceptible host
Immuno compromised, age, nutrition, social economic factors, open wounds, invasive procedures, already infected
Why are hospital patients more susceptible to infections
Because they are already ill, Have more exposure, more infections micro organisms, immunosuppressives drugs, surgery and invasive procedures
How do you break the chain of infection
Identify micro organism, disinfect and sterilise, check employer health e.g. their vaccines, clean hospital, masks, aseptic technique, gloves for handling waste, single patient room, PPE, maintain skin and personal hygiene and diet and fluids
What do you use for droplet precautions
Masks
What do use for airborne precautions
General masks don’t work so they use NP5 masks
What is an acute infection
Where the virus infects the host
What is a chronic infection
Continue infection beyon when immune system should clear it
What is a Latent infection
The infection enters the DNA genome – DNA viruses go to the retro virus infection which triggers cellular transformation and the genome and keeps dividing
What is an asymptomatic infection
Infection with no symptoms
When is the incubation period
In the latent and asymptomatic parts of infection
Due to virulence professional pathogens
Always cause disease
Due to virulence opportunist pathogens
Sometimes cause disease
What is pathogenicity
Probability that an organism is causing disease, it depends on virulent, where it is and immune state of patient
What does the coagulative test do
Stimulates clotting in staphylococcus aureus
S.aureus infection how does it occur
Staphylococcus aureus lives in the nose and can cause infection in the skin or through food poisoning
The innate immune system is very sensitive to
Lipopolysaccharide recognition
Lipopolysaccharide recognition
LPS interacts with the TLR4 toll like receptors which causes an inflammatory response, coagulation and clotting pathways
Gram-negative bacteria in the blood cause
Systemic activation of immune response
What does clostridium difficile do
In the elderly mainly it causes diarrhoea, it makes toxins, produces spores and some very large strains
