CSI 3

Question 1

What are the types of HAI

Answer 1

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

Question 2

What are the risk factors for HAIs?

Answer 2

Type of medical procedure
Antibiotic use
Length of stay at hospital
Organisational factors
Patient characteristics
Behaviour of healthcare providers

Question 3

What is the epidemiological triad model?

Answer 3

Agent leaves reservoir or host
Through portal of exit
Mode of transmission through portal of entry to infect a susceptible host

Question 4

What is a reservoir?

Answer 4

Infectious agents live, grow and multiply here.

Question 5

What are human reservoirs like?

Answer 5

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,

Question 6

What are the types of carriers

Answer 6

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.

Question 7

What is zoonosis?

Answer 7

Diseases that can spread from vertebrae animals to humans under natural conditions

Question 8

Examples of zoonosis

Answer 8

Brucellosis - cows and pigs
Anthrax - sheep
Plague - rodents
Trichinosis - swine
Tularemia - rabbits
Rabies - bats, raccoons, dogs
West Nile encephalitis - birds
Monkeypox - prairie dogs

Question 9

Examples of environmental reservoirs

Answer 9

Plants, soil and water

Question 10

What are the 2 categories of transmission

Answer 10

Direct and indirect

Question 11

What are the 2 types of direct transmission?

Answer 11

Droplets
Direct contact

Question 12

What are the types of indirect transmission

Answer 12

Vehicleborne
Airborne
Vectorborne

Question 13

What is a fomite?

Answer 13

An inanimate object such as a handkerchief, bedding or surgical scalpels that may indirectly transmit an infectious agent.

Question 14

Public health interventions include :

Answer 14

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

Question 15

Groups impacted by HAIs?

Answer 15

NHS
Healthcare setting
Healthcare workers
Patient
Patient’s family
Visitors

Question 16

Impact on patient of HAI

Answer 16

Anger
Increased stay in hospital
Confusion
Loss of trust in NHS
Mortality
Potential readmission

Question 17

Impact on patients family

Answer 17

Anger
Confusion, ill informed
Loss of trust
Financial stress if patient not working

Question 18

Healthcare workers impact HAI

Answer 18

Worry about self being infected
Time off work due to infection affecting peers

Question 19

HAI impact on NHS

Answer 19

Financial cost
Bed pressure
Staff off work
Total cost is £2 billion

Question 20

Chain of infection

Answer 20

Pathogen
Reservoir
Portal of exit
Transmission
Portal of entry
Susceptible host

Question 21

How to break the chain of infection

Answer 21

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

Question 22

Antibiotic sensitivity test

Answer 22

Add disk to plate
Look at how well bacteria have grown
Zone of inhibition

Question 23

How do bacteria mutate?

Answer 23

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

Question 24

What is amoxicillin

Answer 24

A type of beta lactam antibody (contains a beta lactam ring) and is a penicillin derivative

Question 25

What is coamoxiclav and how is it useful?

Answer 25

It is amoxicillin + clavulanic acid. The clavulanic acid inhibits beta lactamse (which breaks down the beta lactam ring in amoxicillin). The amoxicillin can then inhibit D-alanyl-D-alanine transpeptidase (used to make the peptidoglycan membrane). The cell wall does not form so the bacteria cannot survive.

Question 26

What are antimicrobials

Answer 26

Drugs that treat many types of infections by killing or slowing the growth of pathogens causing that infection

Question 27

How do gram negative bacteria restrict access of antibiotics?

Answer 27

They have an outer plasma membrane layer that protects them from their environment.

Question 28

How does resistance spread?

Answer 28

Conjugation: Plasmids can be shared
Transformation: Transposons are small pieces of DNA that can go into and change the overall DNA of a cell. These can move from chromosomes to plasmids and back.
Transduction: Phages are viruses that can attack and carry DNA between bacteria.

Question 29

Example of destroying antibiotic

Answer 29

Klebsiella pneumoniae bacteria produce enzymes called carbapenemases which break down carbapenem drugs and most other beta lactam drugs

Question 30

Example of changing targets

Answer 30

E coil changes mcr-1 gene adds a compound to the outside of the cell wall so that colistin cannot latch on to it.

Question 31

Example of bypass the effects of the antibiotics

Answer 31

Staphylococcus aureus bacteria can bypass the drug effects of trimethoprim