CMB1003/L10 Treatment of Bacterial Infections

Question 1

Describe late agglutination/ bead equivalent.

Answer 1

Exploiting antibody-antigen interactions for rapid diagnostics
Confirm identity of isolates
Identify known pathogen-associated antigens in specimens when isolation fails

Question 2

What is serology? (3)

Answer 2

Relies on diagnostic identification of antibodies in the serum
E.g., latex agglutination tests
Only relevant antigens will be bound by specific antibody

Question 3

What is serotyping? (2)

Answer 3

Determines the subtype of the organism
Allows effective treatment

Question 4

Give 3 advantages to molecular diagnosis of infections.

Answer 4

Bacterial genomes are unique
Genetic material can be extracted from infected specimens
DNA is easy to detect and quantify
Extremely sensitive 1-10 CFU

Question 5

Give 3 disadvantages of molecular diagnosis of infections.

Answer 5

Technology is still being developed
Some tests require bacteria to be isolated first
Some tests are too sensitive
Standardisation from lab to lab can be problematic

Question 6

How can PCR be modified to detect DNA sequences? (2)

Answer 6

Add fluorescent DNA intercalating agent to finished reaction or other fluorescent DNA binding dyes
Add dyes to PCR without inhibiting it and detect PCR product in real-time

Question 7

Give a successful example of RT-PCR.

Answer 7

Meningitis - pre-emptive treatment before CSF specimen collection
Whooping cough - RT-PCR diagnosis within hours rather than 3-12 days

Question 8

Give an example of a bactericidal drug.

Answer 8

Penicillin

Question 9

Give an example of a bacteriostatic drug.

Answer 9

Chloramphenicol

Question 10

Give 3 antibiotic targets.

Answer 10

Cell wall
DNA/RNA synthesis
Folate synthesis
Cell membrane
Protein synthesis

Question 11

How can bacteria become resistant to cell wall-targeting antibiotics?

Answer 11

Producing pumps to cause efflux of the antibiotic

Question 12

How can bacteria become resistant to DNA/RNA synthesis-targeting antibiotics?

Answer 12

Producing inactivating enzymes

Question 13

Describe the mechanism by which chloroamphenicol, macrolides and lincosamides work. (3)

Answer 13

Bind to 50S ribosomal subunit
Prevent peptide bond formation
Stop protein synthesis

Question 14

Describe the mechanism by which aminoglycosides work. (2)

Answer 14

Bind to 30S ribosomal subunit
Impair proofreading, resulting in production of faulty proteins

Question 15

Describe the mechanism by which tetracyclines work. (3)

Answer 15

Bind to 30S ribosomal subunit
Block binding of tRNAs
Inhibit protein synthesis

Question 16

Define minimum inhibitory concentration (MIC).

Answer 16

The minimum concentration of antibiotic needed to inhibit growth

Question 17

How can current approaches be modified for treating infections? (3)

Answer 17

Limiting antibiotic use
Last resort antibiotics
Combination therapy
Phage therapy
Faecal transplant

Question 18

What information is required when an outbreak occurs? (4)

Answer 18

Reported by whom and where
Type of outbreak suspected
Who is affected
Population at risk

Question 19

Why is global monitoring required? (4)

Answer 19

Health education and protection can limit spread
Monitoring outbreaks can prevent an epidemic
In field diagnostics now available
Transient population and air travel mean no infection barriers

Question 20

What is Q-POC Platform?

Answer 20

A rapid multiplex PCR testing system that delivers results in approximately 30 minutes at the point of need

Question 21

What is Q-POC SARS-CoV-2 Assay?

Answer 21

A quality rapid COVID-19 PCR assay that provides results with the simplicity and hands on time of a lateral flow test