L3 Medically Relevant Infections, Treatment & Evolution

Question 1

How does the healthcare environment contribute to the incidence of infectious diseases?

Answer 1

In a healthcare setting, HCAI (healthcare acquired infections) can be promote atypical/resistant organisms compared to community-acquired infections because of:

• older & vulnerable hosts
• frequent contacts between patients and carers
• use of antimicrobials

Question 2

What does MRSA stand for?

Key virulence factors

Answer 2

Methcillin-resistant Staphylococcus aureus.
Virulence factors:
- poor patient outcomes
- lead to sepsis, fascilitis or pneumonia, infective endocarditis

Question 3

pathophysiology and characteristics of Staphylococcus aureus

Answer 3

gram-positive 
grape-like clusters 
transmission via contact with pus/skin 
Pyogenic (pus-producing infections) 
Toxin-mediated infections (e.g. food poisoning)

Question 4

4 types: transfer of resistance genes

Answer 4

1. transformation
2. transduction
3. conjugation
4. transposition

Question 5

Examples of antibiotic misuse leading to antimicrobial resistance

Answer 5

1. poor prescribing
2. use of broad spectrum antibiotics
3. poor patient adherence

Question 6

Resistance mechanisms

Answer 6

1. production of enzyme
   - enzymatic inactivation of antibiotic
2. alteration of bacterial cell binding site
3. change in membrane permeability
4. producing alternate metabolic pathways/drug efflux pump

Question 7

Do antimicrobials cause resistance?

Answer 7

HELL NAH DAWG.
It DOES NOT CAUSE RESISTANCE, but favors the survival of resistant strains that already exists in the population via selective pressure

Question 8

5 classes of antibiotics

Answer 8

1. cell metabolism
2. cell wall synthesis
3. protein synthesis
4. nucleic acid synthesis
5. cell membrane function

Question 9

4 types of antimicrobials

Answer 9

1. anti-parasitic (eukaryotic)
2. anti-fungal (eukaryotic)
3. anti-viral
4. anti-bacterial (antibiotics)

Question 10

What are some key factors for effective antimicrobial therapy?

Answer 10

• narrow spectrum (doesn’t affect normal flora)
• selective toxicity (few side effects)
• routes of administrations (e.g. tablets over injection)
• good distribution to site of infection
• emergence of resistance is slow

Question 11

What is the prime target of antimicrobial therapy?

Answer 11

It’s essential function is to target the pathogen of concern that is unique (ish) so that it only kills that targeted pathogen and nothing else.
i.e. it only targets pathogen and not the host.

Question 12

Name HCAI of highest concern.

Answer 12

• Multi-resistant organisms (e.g. MRSA = methilicilin-resistant Staphylococus aureus)
• Clostridioides difficile (Clostridium difficile)
• Urinary tract infections
• Respiratory syncytial virus (RSV)
• Rotavirus

Question 13

Why is antibiotic therapy controversial for C. difficile treatment?

Answer 13

Antibiotic therapy is linked with recurrence in C. difficile since taking antibiotics was the reason why this infection could thrive in the first place.

Question 14

What is a major virulence factor for UTI’s ?

Answer 14

pili is able to adhere to epithelial cells; strong attachment to cells enabling it to spread and grow

Question 15

Human practices that can lead to antibiotic resistance, what can be done to prevent it?

Answer 15

Ensure patient adheres and completes course of antibiotics.
Appropriate antibiotic dosage for patients.
Reduce usage of broad-spectrum antibiotics.