Mechanisms of Antibiotic Resistance

Question 1

How does natural resistance occur?

Answer 1

Target is not present (eg no cell wall), target not accessible, developmental structure/state (persistor cells and biofilms more resistant), and metabolism

Question 2

What are biofilms?

Answer 2

Communities of micro-organisms in a 3D structure with interfaces - resistant to antimicrobial agents and host defences

Question 3

What is a persistor cell?

Answer 3

Tolerant, metabolically inert subpopulation of cells - enriched in biofilms

Question 4

What are the 3 types of horizontal gene transfer?

Answer 4

Transformation (natural competence), transduction (bacteriophage) and conjugation (sex pili)

Question 5

Cross resistance vs multiple resistance

Answer 5

Cross - single mechanisms related to antibiotics

Multiple - multiple mechanisms unrelated to antibiotics

Question 6

What are the mechanisms of antimicrobial drug resistance?

Answer 6

Altered permeability (influx and efflux) and inactivation (beta-lactamase - ESBL, and chloramphenicol acetyl transferase)

Question 7

What do beta-lactamases do?

Answer 7

Break open the beta-lactam ring