Antibiotics And Antivirals

Question 1

What are the causative organisms for meningitis in children and adults?

Answer 1

Neisseria meningitidis

Streptococcus pneumoniae

Question 2

What are the causative organisms of meningitis in neonates?

Answer 2

Escherichia coli
Listeria monocytogenes
Group B streptococcus

Question 3

What are the 2 main uses of antibiotics?

Answer 3

1. Prevention of infections in people at higher risk e.g. Elderly, immunocompromised, peri-operative
2. Treatment of significant bacterial infections

Question 4

What are the 2 types of bacterial resistance?

Answer 4

Innate - bacteria has never been sensitive to ABX.

Acquired - bacteria was once sensitive to ABX, but is now resistant.

Question 5

What does ‘sensitive’ mean in terms of antibiotics?

Answer 5

That the antibiotic successfully prevents growth of the bacteria.

Question 6

In antibiotic disc testing, what do large and small zones of inhibition mean?

Answer 6

Large - bacteria is sensitive.

Small/none - bacteria is resistant.

Question 7

What is minimum inhibitory concentration (MIC)?

Answer 7

The lowest concentration of a drug that prevents visible growth of bacteria.

Question 8

Name the 2 ways that antibiotics kill bacteria.

Answer 8

Time-dependent killing - need prolonged ABX but not at a high concentration.
Concentration-dependent killing - need a high concentration of ABX but not for long.

Question 9

Name a drug that requires therapeutic drug monitoring.

Answer 9

Gentamicin - gent levels need to be checked with a blood test a few hours after the dose because it has a very narrow therapeutic window.

Question 10

What type of virus is the influenza virus?

Answer 10

Retrovirus - contains RNA

Question 11

Describe the influenza virus life cycle.

Answer 11

• hemaglutinin proteins on surface allow virus to bind to host cell
• virus invades host cell
• viral RNA integrates into host DNA
• viral RNA is transcribed and translated
• virus is excreted from the host cell that it can continue infecting cells

Question 12

What is the purpose of M2 ion channels on the influenza virus?

Answer 12

Allow the entrance of H+ into the virus, which is vital in allowing the virus to break up and replicate.

Question 13

How does the influenza vaccine work?

Answer 13

Blocks the virus from sticking to host cells.

Question 14

What are M2 ion channel inhibitors used for and what is their MOA?

Answer 14

Influenza

Stop the virus breaking up and integrating into other host cells.

Question 15

What are neuraminidase inhibitors used for and what is their MOA?

Answer 15

Influenza treatment
Block the enzyme neuraminidase, which is required for breaking the binding between sialic acid and hemaglutinin so that the virus can bud off and infect other host cells - means that virus can’t cause further infection.

Question 16

Name 2 neuraminidase inhibitors.

Answer 16

Zanamivir

Oseltamivir

Question 17

What is oseltamivir often used for?

Answer 17

Neuraminidase inhibitor used for influenza treatment but often given as seasonal prophylaxis to people who are at high risk e.g. Elderly, immunocompromised.

Question 18

What is the H5N1 infection?

Answer 18

Bird flu - can cause resistance to neuraminidase inhibitors - this is what caused the swine flu pandemic in 2009.

Question 19

Is the human herpes virus DNA or RNA?

Answer 19

DNA

Question 20

What is significant about the herpes virus?

Answer 20

It can become latent and cause a secondary infection when reactivated.

Question 21

What happens when the varicella zoster virus (type of herpes virus) becomes reactivated?

Answer 21

Shingles

Question 22

What is the difference between herpes simplex 1 and herpes simplex 2?

Answer 22

Herpes simplex 1 - orally spread

Herpes simplex 2 - spread by genital secretions