MRSA and VRE

Question 1

When was the last class of antibiotics developed

Answer 1

30 years ago!

Question 2

How does the use of antibiotics create resistance

Answer 2

There is an increased selective pressure which favours resistant strains of bacteria

Question 3

What are the 5 key resistant bacteria?

Answer 3

Escherichia coli
Klebsiella pneumoniae 
Enterococcus faecium 
Pseudomonas aeruginosa
MRSA

Question 4

Who prescribes the most antibiotics.

Give examples of other prescribers

Answer 4

General Practitioners

Examples - hospital in and outpatient, dentists, community practitioners

Question 5

When are narrow spec antibiotics commonly used?

Answer 5

When the infection they are being used to treat is resistant and standard antibiotics are ineffective

Question 6

What are the 3 most commonly prescribed groups of antibiotics in England

Answer 6

Penicillin (45%)
Tetracycline (22%)
Macrolides (15%)

Question 7

What is the defined daily dose

Answer 7

A statistical measure of drug consumption

Question 8

What does MRSA stand for?

Answer 8

Meticillin resistant Staphylococcus aureus

Question 9

Which antibiotics are MRSA resistant to?

Answer 9

All beta lactams (penicillin, cephalosporins, carbapenems)
And ….
Many strains are also resistant to
Macrolides (erythromycin),quinolones (ciprofloxacin) and clindamycin

Question 10

Describe 2 resistant the mechanisms of MRSA

Answer 10

1. Expression of the alternative form of penicillin binding protein (PBP2) called PBP2a which has a reduced binding affinity for the antibiotic.
2. Production and release of the beta-lactamase enzyme which cleaves and inactivated antibiotics molecules.

Question 11

Explain the concept of MRSA colonisation

Answer 11

Patients may be colonised with mrsa (on their skin, nose groin and armpit in particular). Colonisation means they carry it without it causing any symptoms. If an individual then enters a situation where bacterial infection is higher (such as surgery) the likelihood of them developing an mrsa infection is greatly increased as it is already associated with their body

Question 12

Who are most at risk of developing an MRSA infection?

Answer 12

Nursing home residents and frequent hospital attendees

Question 13

How do hospitals reduce the likelihood of MRSA infection?

5 ways

Answer 13

Screening at risk patients (take swabs looking for bacterium)
Isolate patients which tesct positive for MRSA
Decontamination therapy - an antiseptic solution used as a mouthwash, skin wash and nasal ointment. This helps to remove a large portion of the bacteria on/in the patient
Hand washing (all visitors)
Aseptic non touch techniques for care

Question 14

What is the difference between MRSA colonisation and MRSA infection?

Answer 14

Colonised patients will not show any symptoms. They only need to decontamination when coming into hospital

Patients with an infection will have symptoms associated with an infection- high temperature, high whit cell count, inflammation at the infection site etc

Question 15

What are the first and second line treatments for systemic infections of MRSA

Answer 15

1st line - IV glycopeptides - vancomycin or teicoplanin

2nd line - linezolid, daptomycin and tigecycline (much more expensive)

Question 16

What dies GRE stand for?

Answer 16

Glycopeptide Resistant Enterococci

Question 17

Where are patients colonised with GRE

Answer 17

In the gut. Enterococci are gram positive gut dwelling organisms. Are often associated with IV lines

Question 18

How do Vancomycin resistant enterococci become antibiotic resistant?

Answer 18

The usual cell wall precursors synthesised by the bacteria contain a tripeptide intermediate (-D-Ala-D-Ala) which is crucial for cell wall synthesis
The resistant bacteria, in the presence of vancomycin, make cell wall precursors that have low affinity for vanvomycin (they have a different peptide sequence)

Question 19

Give examples of the misuse of antibiotics

6

Answer 19

Unnecessarily prescribed
Delayed administration to critically ill patients
Broad spec used to generously, narrow spec used incorrectly
Sub theraputic dosing
Overdosing
Too long/short a course
Treatment isn’t streamlined

Question 20

What is antibiotic stewardship

Answer 20

Health promotion to avoid antibiotic use when its not needed and ensuring they are used rationally

Question 21

Has antibiotic use increased or decreased in the past few years

Answer 21

Increased

Question 22

Outline the main characteristics of c. Difficile

Answer 22

Name - clostridioides difficile
Gram positive, anaerobic
Infects the intestines

Question 23

What causes C. Difficile infections

Answer 23

A disturbance of the colon microbiome (often by antibiotics) which allows the bacteria tkmtiply rapidly and produce a toxin. This toxin is what causes the symptoms

Question 24

C. Difficile produce spores. What impact does this have on infection control?

Answer 24

Spores can survive for a long time in the environment (they’re not susceptible to alcohol washes) so methods of infection control are crucial to stop its spread

Question 25

What are the treatments for C Difficile

Answer 25

Stop precipitating antibiotics if possible
Stop anti diarrhoeal agents
Stop gastric acid suppressants
Stop laxatives

Treatments
Mild disease - ORAL metronidazole
Severe disease - ORAL vancomycin

Question 26

Why is it important to qdminister medicines for C. Difficile orally?

Answer 26

As the bacteria reside in the GI tract, they must be treated with drugs that work in this area