Antimicrobials and Resistance

Question 1

Inhibition of cell wall synthesis

Answer 1

B lactam antimicrobials
Polypeptide antimicrobials
Glycopeptide antimicrobials

Question 2

B lactam antimicrobials

Answer 2

contain B lactam ring
differentiated by the chemical side chains attached to the ring
prevent cross linking of peptidoglycan

Question 3

B lactam antimicrobials mode of action

Answer 3

ability to inhibit PBPs that are essential for peptidoglycan synthesis

Question 4

PBPs

Answer 4

transpeptidases that cross link peptidoglycan

located on the external side of the bacterial plasma membrane

Question 5

Penicillins

Answer 5

Penicillin
Ampicillin
Oxacillin

Question 6

Carbapenems

Answer 6

Meropenem

Question 7

Monobactem

Answer 7

Aztreonem

Question 8

Cephalosporins

Answer 8

1-5th gen

Question 9

Polypeptide antimicrobials

Answer 9

Bacitracin

Question 10

Bacitracin

Answer 10

inhibits synthesis of cell wall at an earlier stage than B lactam antimicrobials
interferes with synthesis of the linear carbohydrate strands for peptidoglycan

Question 11

Glycopeptide antimicrobials

Answer 11

Vancomycin

Question 12

Vancomycin

Answer 12

inhibition of cell wall synthesis by complexing with the D-alanyl-D-alanine portion of the peptide cross links

Question 13

B lactam antimicrobials

Answer 13

penicillins
carbapenems
monobactem
cephalosporins

Question 14

Inhibition of protein synthesis

Answer 14

chloramphenicol
aminoglycosides
tetracyclines
macrolides
lincosamides

Question 15

Chloramphenicol

Answer 15

binds to 50S portion and inhibits formation of peptide bond

Question 16

Aminoglycosides

Answer 16

changes shape of 30S portion, preventing 50S ribosome from forming 70S complex causing code on mRNA to be read incorrectly

Question 17

Tetracyclines

Answer 17

interfere with attachment to tRNA to mRNA - 30S ribosome complex

Question 18

Macrolides

Answer 18

bind to 50S subunit blocking the translocation reaction of polypeptide chain elongation

Question 19

Lincosamides

Answer 19

bind to 50S subunit blocking the translocation reaction of polypeptide chain elongation

Question 20

Inhibition of nucleic acid replication and transcription

Answer 20

Rifamycin

Fluoroquinolones

Question 21

Rifamycin

Answer 21

forms a complex with bacterial RNA polymerase preventing the initiation process of DNA transcription

Question 22

Fluoroquinolones

Answer 22

block bacterial DNA synthesis by inhibiting bacterial topoisomerase II (DNA gyrase) and topoisomerase IV (ciprofloxacin, levofloxacin)

Question 23

Injury to plasma membrane

Answer 23

lipopeptides

Question 24

Lipopeptides

Answer 24

daptomycin

polymyxin B

Question 25

Daptomycin

Answer 25

binds to cell membrane and alters structure making it more permeable which leads to cell death

Question 26

Polymyxin B

Answer 26

interacts with phospholipids of bacterial cell membranes increasing cell permeability and causing cell lysis

Question 27

Inhibition of essential metabolite synthesis

Answer 27

sulfonamides | trimethoprim

Question 28

Sulfonamides

Answer 28

structurally similar to folic acid precursor (PABA), allowing them to competitively bind with the enzyme meant for PABA and thereby block folic acid production

Question 29

Folic acid

Answer 29

important coenzyme in bacteria needed for synthesis of proteins

Question 30

Trimethoprim

Answer 30

structurally similar to dihydrofolic acid allowing for competitive inhibition of enzyme meant for dihydrofolic acid thereby blocking folic acid production

Question 31

Bacterial enzymatic destruction of antimicrobial agent

Answer 31

B lactamase mediated resistance

Question 32

B lactamase mediated resistance

Answer 32

able to break down some penicillins, cephalosporins, and carbapenems

Question 33

Bacterial enzymatic alteration of antimicrobial agent

Answer 33

aminoglycoside resistance

Question 34

Aminoglycoside resistance

Answer 34

bacterial enzymes modify aminoglycosides resulting in decreased binding to 30S ribosome therefore making the antimicrobial inactive

Question 35

Efflux (ejection) of antimicrobial agent from bacteria

Answer 35

Tetracycline resistance

Question 36

Tetracycline resistance

Answer 36

efflux pump removes antimicrobial from cytoplasm so that it can't interfere with tRNA attachment so proteins synthesis can continue

Question 37

Alteration of the antimicrobial agents target site

Answer 37

Oxacillin (methicillin) resistance | Vancomycin resistance

Question 38

Oxacillin (methicillin) resistance

Answer 38

penicillin binding protein mediated resistance | MRSA has PBP2a coded by mecA gene

Question 39

Vancomycin resistance

Answer 39

altered peptidoglycan cross link target so vancomycin can't bind and prevent the transpeptidase cross linking of peptidoglycan vanA and vanB most common genes coding for resistance

Question 40

Blocking entry to antimicrobial agents target site in bacteria

Answer 40

B lactam, Tetracycline, and Fluoroquinolone resistance

Question 41

B lactam, Tetracycline, and Fluoroquinolone resistance

Answer 41

porin channel mediated blocked entry prevents antimicrobial from reaching target site

Question 42

Target bypass

Answer 42

Trimethoprim/Sulfamethoxazole resistance

Question 43

Trimethoprim/Sulfamethoxazole resistance

Answer 43

Bacteria increases the production of the antimicrobial target with the objective of overwhelming the antibiotic by increasing the amount of targets available 2 enzymes DHFR or DHPS are overproduced through mutations in the DNA encoding these enzymes so folate production can continue