Javier Ratchett - Hospital Acquired Infection Flashcards
(39 cards)
Describe the chain of infection
1) Agent leaves reservoir/ host through portal of exit
2) This is conveyed via some mode of transmission
3) Enters through appropriate portal of entry to infect susceptible host
What is a resevoir?
Habitat that the infectious agent normally lives and multiplies in eg. humans, animals environment
What is the portal of the exit?
The path by which pathogen leaves the host and usually the site where the pathogen is localised
What are the different modes of transmission?
DIRECT
- Direct contact
- Droplet spread
INDIRECT
- Airborne
- Vehicleborne
- Vectorborne
What is the portal of entry?
The manner in which pathogens enter susceptible hosts
What is the impact of HAIs on healthcare systems
- Increases bed pressure
- 2 billion pound cost for the NHS
- 60 000 days lost healthcare workers contracting HAIs
- Increase in mortality and morbidity
- More complaints and dissatisfaction
What is meant by zoonosis
Infectious disease that is transmissible under natural conditions from vertebrae animals to humans
What are the 4 main risk factors of HAIs?
- Medical procedures and antibiotic uses
- Organisational factors
- Patient characteristics
- Behaviour of healthcare staff
If someone has an infection, what are their WBC count, CRP level and respiratory rate?
WBC count - High
CRP level - High
Respiratory rate - High
What is D-alanyl-D-alanine carboxypeptidase transpeptidase also known as and what is its function?
- Penicillin Binding Protein
- Assists with peptidoglycan matrix assembling by creating crosslinks between chains
What are the mechanisms in which bacterial resistance occurs?
- Decreased uptake of drug
- Mutated channel so drug cannot enter
- Enzyme digests/breaks down drug
- Inactivating enzymes
- Horizontal gene transfer
- Alternative enzyme to bypass the reaction that the drug inhibits
How do antibiotics inhibit D-alanyl-D-alanine carboxypeptidase?Ho
Antibiotics binds to the enzyme and inhibits the action of it preventing it from forming the cross links in the peptidoglycan layer, killing the bacteria.
How do bacteria evade beta-lactam containing antibiotics
They can express a beta-lactamase enzyme which breaks beta-lactam of antibiotic, rendering the antibiotic useless
Why would a patient not respond to amoxicillin but respond to co-amoxiclav
Bacteria inhibits amoxicillin via beta lactamases but co amoxiclav contains clavulanic acid which inhibits those beta lactamases therefore the amoxicillin has can inhibit the bacteria
Why would a patient taking co-amoxiclav develop a C.difficile infection
The antibiotic reduces gut flora therefore decreases competition for c.diff and so creates an environment that c.difficile can survive in.
What is sepsis?
Body’s extreme response to an infection which can rapidly lead to tissue damage, organ failure and death
What is the sequence of septic shock?
Hypotension(low BP)
tachycardia (high heart rate)
tachypnoea(high respiratory rate)
What can sepsis lead to?
- Tissue damage
- Organ failure
- Death
What is hospital acquired infection?
An infection that patients get while receiving treatment for medical or surgical conditions
When are HAIs usually acquired?
- During procedures such as surgery
- From devices used in medical procedures such as catheters and ventilators
Can be HAIs be caused by microorganisms already present in the patient’s body? How?
YES - Medical procedures can weakend the body’s defences causing them to be more susceptible to infection.
Where is the most common place for a patient to contract an HAI?
Outpatient settings
What is CLABSI?
Central line associated bloodstream infections
What is MRSA?
Methicillin resistant staphylococcus aureus
