CSI 3 Flashcards
What are the types of HAI
Central line-associated bloodstream infection
Methicillin resistant staphylococcus aureus infection
Catheter-associated urinary tract infection
Ventilator associated infection
Surgical site infection
Bloodstream infection
Clostridium difficile infection
Pneumonia
What are the risk factors for HAIs?
Type of medical procedure
Antibiotic use
Length of stay at hospital
Organisational factors
Patient characteristics
Behaviour of healthcare providers
What is the epidemiological triad model?
Agent leaves reservoir or host
Through portal of exit
Mode of transmission through portal of entry to infect a susceptible host
What is a reservoir?
Infectious agents live, grow and multiply here.
What are human reservoirs like?
Most diseases are have human reservoirs. E.g STDs, measles, mumps, streptococcal infection and many respiratory pathogens. As humans were the on,y natural reservoir for the smallpox virus, it was eradicated after the last human case was identified and isolated,
What are the types of carriers
Asymptomatic/passive/healthy - Never experience symptoms despite being infected.
Incubatory carriers - transmit the agent during the incubation period.
Convalescent carriers - have recovered but still able to transmit the disease.
Chronic carriers - Continue to have the pathogen for months or even years after initial infection.
What is zoonosis?
Diseases that can spread from vertebrae animals to humans under natural conditions
Examples of zoonosis
Brucellosis - cows and pigs
Anthrax - sheep
Plague - rodents
Trichinosis - swine
Tularemia - rabbits
Rabies - bats, raccoons, dogs
West Nile encephalitis - birds
Monkeypox - prairie dogs
Examples of environmental reservoirs
Plants, soil and water
What are the 2 categories of transmission
Direct and indirect
What are the 2 types of direct transmission?
Droplets
Direct contact
What are the types of indirect transmission
Vehicleborne
Airborne
Vectorborne
What is a fomite?
An inanimate object such as a handkerchief, bedding or surgical scalpels that may indirectly transmit an infectious agent.
Public health interventions include :
Controlling or eliminating agent at source if transmission - treating patients, educating patients on how contact can lead to disease, changing environment of patient, changing ventilation, targeting vector breeding.
Protecting portals of entry - Herd immunity
Increasing host’s defences - vaccinations, prophylactic use of antimalarial drugs
Groups impacted by HAIs?
NHS
Healthcare setting
Healthcare workers
Patient
Patient’s family
Visitors
Impact on patient of HAI
Anger
Increased stay in hospital
Confusion
Loss of trust in NHS
Mortality
Potential readmission
Impact on patients family
Anger
Confusion, ill informed
Loss of trust
Financial stress if patient not working
Healthcare workers impact HAI
Worry about self being infected
Time off work due to infection affecting peers
HAI impact on NHS
Financial cost
Bed pressure
Staff off work
Total cost is £2 billion
Chain of infection
Pathogen
Reservoir
Portal of exit
Transmission
Portal of entry
Susceptible host
How to break the chain of infection
Handwashing:
1 before touching patient
2 before a clean aseptic procedure
3 after body fluid exposure risk
4 after touching patient
5 after touching patient surroundings
Antibiotic sensitivity test
Add disk to plate
Look at how well bacteria have grown
Zone of inhibition
How do bacteria mutate?
1 changing enzymes
2 changing receptors
3 inactivation of antibiotic
4 alter metabolism so that the process that the antibiotic targets is no longer important.
5 Efflux pumps throw antibiotic out
6 decreased uptake - cell membrane change so AB can’t get in. Gram negative can so this particularly well because of double membrane
7 target alterations
What is amoxicillin
A type of beta lactam antibody (contains a beta lactam ring) and is a penicillin derivative
