Hospital Acquired Infections

Question 1

Define the following:

a. Antimicrobial
b. Antibacterial
c. Antibiotic

Answer 1

Antimicrobial: Interferes with growth + reproduction of a microbe
Antibacterial: agents that reduce/ eliminate harmful bacteria
Antibiotic: Antimicrobial used as medicine for humans + animals

Question 2

What is a health-care associated infection?

Answer 2

Infections that occur after exposure to healthcare

Infection starts >48 hours after admission to hospital

Question 3

Why do health-care associated infections cost money to the healthcare system?

Answer 3

Increase length of stay at hospital

Question 4

List 5 medical interventions that can increase the risk of infection.

Answer 4

Catheterisation  
Intubation  
Lines (e.g. central venous lines)  
Chemotherapy 
Prosthetic material

Question 5

State 2 other factors that increase the risk of infection in the hospital setting.

Answer 5

Dissemination by healthcare staff

High conc. of ill patients

Question 6

What are the ESCAPE pathogens?

Answer 6

Enterococcus faecium  
Staphylococcus aureus 
Clostridium difficile 
Acinetobacter baumanii 
Pseudomonas aeruginosa 
Enterobacteriaceae

ESC = Gram-positive  
APE = Gram-negative

Question 7

What is the main problem with the escape pathogens?

Answer 7

They are antibiotic resistant

Question 8

What is the most frequent cause of bacteraemia by a Gram-negative bacterium?

Answer 8

E. coli

Question 9

What does E. coli frequently cause?

Answer 9

UTI

Question 10

Which antibiotics is E. coli resistant to in many countries?

Which antibiotics is E. coli still sensitive to?

Answer 10

Resistant to Cephalosporins

Sensitive to Carbapenems

Question 11

State the target protein and the method of resistance to Methicillin

Answer 11

Target: PBP - inhibits peptidoglycan synthesis
Resistance: alternative target (PBP2A), which has low affinity for methicillin, thus can still synthesise peptidoglycan

Question 12

What is ESBL encoded on?

Answer 12

Plasmid

Question 13

What are carbapenemases encoded on?

Answer 13

Transposon (mobile genetic element)

Question 14

What types of infections does Klebsiella pneumoniae tend to cause?

Answer 14

UTI

Respiratory tract

Question 15

Which classes of antibiotics are Klebsiella widely resistant to?

Answer 15

Cephalosporins, fluoroquinolones + aminoglycosides

Carbapenem resistance in the US

Question 16

Which group of patients are at risk of Klebsiella and P. aeruginosa infection?

Answer 16

Immunocompromised

Question 17

Which class of antibiotics is P. aeruginosa widely resistant to?

Answer 17

Carbapenems

Question 18

What is the most important cause of antimicrobial resistant infection in the world?

Answer 18

MRSA

Question 19

What is Enterococcus faecium widely resistant to? What does it cause?

Answer 19

Vancomycin

Causes blood stream infections

Question 20

State the target protein and method of resistance to Cephalosporins

Answer 20

Target: Penicillin binding proteins (PBP) - inhibits peptidoglycan synthesis
Resistance: Extended-Spectrum Beta-Lactamase (ESBL) enzyme cleaves cephalosporin, inactivating it

Question 21

State the target protein and method of resistance to Carbapenems

Answer 21

Target: PBP - inhibits peptidoglycan synthesis
Resistance: Carbapenemase enzymes cleave Carbapenem, inactivating it

Question 22

State the target protein and method of resistance to Vancomycins

Answer 22

Target: peptidoglycan precursor - inhibits peptidoglycan synthesis
Resistance: synthesis of a different peptidoglycan precursor

Question 23

What are clinicians forced to use as a result of the resistance in ESCAPE pathogens?

Answer 23

Older, previously discarded drugs associated with significant toxicity with lacking data to guide dosage e.g. Colistin

Question 24

List 3 B lactam antibiotics

Answer 24

Cephalosporins
Carbapenems
Methicillins