antibiotics+ antifungals

Question 1

DIAGRAM classes of antibiotics affect DNA+protein synthesis

Answer 1

target nucleic acid synthesis (SULPHONAMIDES inhibit DHOP synthase= less DHOP produced from PABA) (TRIMETHOPRIM inhibits DHF reductase= less THF produced from DHF), target DNA replication (FLUOROQUINOLONES inhibit DNA gyrase/topoisomerase), target RNA synthesis (RIFAMYCIN inhibits RNA polymerase), target protein synthesis (MACROLIDES inhibit ribosomes, which are different to ours)

Question 2

classes of antibiotics affects cell wall+ which type of bacteria have LPS

Answer 2

target peptidoglycan synthesis- GLYCOPEPTIDES eg vancomycin bind to pentapeptide to prevent synthesis, target peptidoglycan transportation: beta lactams like CARBAPENEMS, CEPHALOSPORINS and PENICILLINS bind to transpeptidase, preventing incorporation into cell wall: cell wall stability- LIPOPEPTIDE disrupts gram+ cell walls, POLYMYXINS disrupts LPS+ cell membrane of gram- bacteria

Question 3

mechanisms of antibiotic resistance

Answer 3

beta lactamases, producing ANOTHER enzyme unaffected by drug, producing a DIFFERENT enzyme unaffected by drug (enzyme still effective), alterations in drug permeability, and hyperproduction of DHF reductase

Question 4

beta lactamases+ penicillin

Answer 4

destroy beta lacta ring- some penicillins are beta lactamase resistant ie can evade this mechanism

Question 5

producing another target unaffected by drug example

Answer 5

E-coli produces different DHF reductase enzyme= resistant to trimethoprim

Question 6

producing a different enzyme example

Answer 6

staph aureus causes mutation in topoisomerase= resistance to fluoroquinolones

Question 7

alteration in drug permeability, important in gram- or +

Answer 7

less aquaporins+ more efflux of antibiotic from bacterial cells= less antibiotic into cell, important in GRAM- -

Question 8

hyperproduction of DHF reductase

Answer 8

trimethoprim less effective

Question 9

types of antifungals

Answer 9

azoles eg fluconazole, and pollyenes eg amphotericin

Question 10

mechanism of azole

Answer 10

inhibit cyp51 enzyme involved in production of ergosterol, which are needed for cell membrane of fungi

Question 11

mechanism of poylenes

Answer 11

bind to ergosterol to create pores in cell membrane

Question 12

commonality of azoles/polyenes

Answer 12

both treat SYSTEMIC fungal infections, not superficial