Hospital acquired bacterial infections

Question 1

Define the following:

a. Antimicrobial
b. Antibacterial
c. Antibiotic

Answer 1

a. Antimicrobial
Interferes with growth and reproduction of a microbe
b. Antibacterial
Commonly used to describe agents that reduce or eliminate harmful bacteria
c. Antibiotic
Type of antimicrobial that is used as medicine for humans and 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

They increase the length of stay at hospital

Question 4

List some 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 some other factors that increase the risk of infection in the hospital setting.

Answer 5

Dissemination by healthcare staff

Concentration of ill patients

Question 6

What are the ESCAPE pathogens? Which are Gram +ve and which are Gram -ve?

Answer 6

• Enterococcus faecium
• Staphylococcus aureus
• Clostridium difficile
• Acinetobacter baumanii
• Pseudomonas aeruginosa
• Enterobacteriaceae (Pathogenic e coli, Klebsiella pneumoniae, Enterobacter species)

ESC are Gram-positive
APE are 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?

Answer 10

Cephalosporins

Question 11

Which antibiotics is E. coli still sensitive to?

Answer 11

Carbapenems

Question 12

State the target proteins and the method of resistance to the following classes of antibiotics:

a. Cephalosporins
b. Carbapenems
c. Methicillin
d. Vancomycin

Answer 12

a. Cephalosporins (𝛽-lactam)
Target: Penicillin binding proteins (PBP)
Resistance: Extended-Spectrum Beta-Lactamase (ESBL)

b. Carbapenems (𝛽-lactam)
Target: PBP
Resistance: Carbapenemase enzymes

c. Methicillin (𝛽-lactam)
Target: Penicilin Binding Protein
Resistance: alternative target (PBP2A), which has low affinity for methicillin and can function in its presence

d. Vancomycin
Target: peptidoglycan precursor
Resistance: synthesis of a different peptidoglycan precursor

Question 13

What is Extended spectrum

b-lactamase (ESBL) encoded on?

Answer 13

Plasmid

Question 14

What are carbapenemases encoded on?

Answer 14

Transposon

Question 15

What types of infections does Klebsiella pneumoniae tend to cause?

Answer 15

UTI

Respiratory tract

Question 16

Which group of patients are at risk of Klebsiella infection?

Answer 16

Immunocompromised

Question 17

Which classes of antibiotics are Klebsiella widely resistant to?

Answer 17

Cephalosporins, fluoroquinolones and aminoglycosides

Carbapenem resistance in the US

Question 18

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

Answer 18

Immunocompromised

Question 19

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

Answer 19

Carbapenems

Question 20

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

Answer 20

MRSA

Question 21

What is Enterococcus faecium widely resistant to?

Answer 21

Vancomycin

NOTE: causes blood stream infections