Infectious diseases - diagnostics and treatment

Question 1

how do microorganisms cause infection?

Answer 1

ability to:

• adhere and colonize skin/mucosal surfaces, biofilm formation
• cross skin/mucosal barrier
• cause tissue destruction, inflammation
• produce/secrete toxins
• withstand/avoid immune defences

Question 2

mechanisms of action of antimicrobial drugs

Answer 2

• cell wall synthesis (beta lactams like Penicillins, Cephalosporins)
• nucleic acid synthesis (quinolones (DNA gyrase)
• protein synthesis (tetracyclins, chloramphenicol)

Question 3

how does antimicrobiotic resistance develop?

Answer 3

-enzymatic breakdown
-modification of drug target
-reduced uptake
-elimination by active efflux
(resistance develops by natural selection, spread by horizontal transfer)

Question 4

why is the principle of selection important in the emergence of antibiotic resistance?

Answer 4

• mutation that provides resistance will give the bacterium an advantage in the surroundings only if exposed by antibiotic
• susceptible bacteria will be inhibited, resistant strain will multiply and dominate