beta-lactam inhibitors - penicillin

Question 1

Vary in resistance to gastric acid
 Vary in their oral bioavailability
 Polar compounds
 Not metabolized extensively

Answer 1

penicillins

Question 2

penicillins are excreted unchanged or changed

Answer 2

unchanged

Question 3

penicillins Excreted unchanged in urine via

 Inhibited by probenecid

Answer 3

 Glomerular filtration

 Tubular excretion

Question 4

Tubular excretion of penicillin is Inhibited by —

Answer 4

probenecid

Question 5

Major antibiotics that inhibit cell wall synthesis

Answer 5

Penicillins

Cephalosporins

Question 6

 Partly excreted in bile

Answer 6

Ampicillin and nafcililin

Question 7

penicillins are Derivatives of ?

Answer 7

6-aminopenicillanic acid

Question 8

Plasma half-life of penicillins vary from –

Answer 8

30 min to 1 h

Question 9

Given intramuscularly
Long half-lives
Drug is released slowly
Cross blood-brain barrier when meninges are inflamed

Answer 9

Procaine and benzathine penicillin G

Question 10

penicillin inhibit cell wall synthesis by the following steps

Answer 10

1. Binding of the drug to specific receptors (penicillin-binding proteins [PBPs]) located in the bacterial cytoplasmic membrane
2. Inhibition of transpeptidase enzymes that act to cross-link linear peptidoglycan chains
3. Activation of autolytic enzymes that cause lesions in the bacterial cell wall

Question 11

? hydrolysis of the beta-lactam ring results in the lost of antibacterial activity

Answer 11

Enzymatic

Question 12

 Penicillinases

 Formed by most staphylococci and gram (-) organisms

Answer 12

beta lactamases

Question 13

 Major mechanism for bacterial resistance

Answer 13

beta lactamases

Question 14

Another mechanism of bacterial resistance
responsible for:
 Methicillin resistance in staphylococci
 Penicillin G resistance in pneumococci

Answer 14

Structural changes in target PBPs

Question 15

 Contribute to resistance by impeding access of penicillin to PBPs
 Resistance in some gram (-) rods like P. aeruginosa

Answer 15

Changes in the porin structure in the outer membrane

Question 16

3 types of resistance to penicillin

Answer 16

beta lactamases
Structural changes in target PBPs
Changes in the porin structure in the outer membrane

Question 17

 Prototype Narrow-spectrum penicillinase-susceptible agents

Answer 17

penicillin G

Question 18

PENICILLIN G
	Prototype of narrow-spectrum penicillinase-susceptible agents
	Parenteral 
	Limited spectrum of activity
	Susceptible to beta-lactamases

Answer 18

PENICILLIN G

Question 19

	For infections caused by 
	Streptococci
	Meningococci
	Gram (+) bacilli
	Spirochetes

Answer 19

PENICILLIN G

Question 20

 Drug of choice for syphilis

 Activity against enterococci is enhanced by aminoglycoside

Answer 20

PENICILLIN G

Question 21

 Oral drug

 Oropharyngeal infections

Answer 21

PENICILLIN V

Question 22

Very-narrow-spectrum penicillinase-resistant agents (3)

Answer 22

METHICILLIN (prototype), NAFCILLIN, OXACILLIN

Question 23

 Treatment of known or suspected staphylococcal infections
 Methicillin-resistant S. aureus (MRSA) and S. epidermidis (MRSE) are resistant to other members of this subgroup and often to multiple antimicrobial drugs

Answer 23

METHICILLIN (prototype), NAFCILLIN, OXACILLIN

Question 24

3. Wider spectrum penicillinase-susceptible agents

Answer 24

ampicillin and amoxicillin

PIPERACILLIN and TICARCILLIN

Question 25

```  Wider spectrum than pen G  Susceptible to penicillinases  Uses similar to pen G  Enterococci L. monocytogenes  E. coli P. mirabilis  H. influenzae M. catarrhalis  Enhanced activity in combination with inhibitors of penicillinases  Synergistic (1+1=3) with aminoglycosides in enterococcal and listerial infections ```

Answer 25

ampicillin and amoxicillin

Question 26

 Activity against gram (-) rods  Pseudomonas  Enterobacter  Some cases of klebsiella species  Synergistic action with aminoglycosides  Susceptible to penicillinases  Enhanced activity in combination with inhibitors of penicillinases

Answer 26

PIPERACILLIN and TICARCILLIN

Question 27

toxcity of penicillin

Answer 27

allergy | GI disturbances

Question 28

toxcity of penicillin

Answer 28

allergy | GI disturbances

Question 29

can cause neutropenia

Answer 29

Nafcillin

Question 30

causes maculopapular rashes

Answer 30

Ampicillin

Question 31

causes interstitial nephritis more than other penicillins

Answer 31

Methicillin

Question 32

cross-allergenicity (complete or not)

Answer 32

Complete

Question 33

GI disturbances are caused by

Answer 33

 Oral penicillins especially ampicillin

Question 34

specific GI disturbances

Answer 34

nausea and diarrhea

Question 35

Pseudomembranous colitis | Maybe caused by (2)

Answer 35

direct irritation or by overgrowth of gram (+) organisms or yeasts

Question 36

An antimicrobial drug that can eradicate an infection in the absence of host defense mechanisms; kills bacteria

Answer 36

bactericidal

Question 37

An antimicrobial drug that inhibits antimicrobial growth but requires host defense mechanisms to eradicate the infection; does not kill bacteria

Answer 37

Bacteriostatic

Question 38

Drugs with structures containing a beta-lactam ring: includes the penicillins, cephalosporins and carbapenems. This ring must be intact for antimicrobial action

Answer 38

Beta-lactam antibiotics

Question 39

``` Bacterial enzymes (penicillinases, cephalosporinases) that hydrolyze the beta-lactam ring of certain penicillins and cephalosporins ```

Answer 39

Beta-lactamases

Question 40

Potent inhibitors of some bacterial beta-lactamases used in combinations to protect hydrolyzable penicillins from inactivation

Answer 40

Beta-lactam inhibitors

Question 41

Lowest concentration of antimicrobial drug capable of inhibiting growth of an organism in a defined growth medium

Answer 41

Minimal inhibitory concentration (MIC)

Question 42

Bacterial cytoplasmic membrane proteins that act as the initial receptors for penicillins and other beta-lactam antibiotics

Answer 42

Penicillin-binding proteins (PBPs)

Question 43

Chains of polysaccharides and polypeptides that are cross-linked to form the bacterial cell wall

Answer 43

Peptidoglycan

Question 44

More toxic to the invader than to the host; a property of useful antimicrobial drugs

Answer 44

Selective toxicity

Question 45

Bacterial enzymes involved in the cross-linking of linear peptidoglycan chains, the final step in cell wall synthesis

Answer 45

Transpeptidases

Question 45

Cross allergenicity with penicillins (complete, incomplete, partial) is assumed

Answer 45

Complete cross allergenicity must be assumed

Question 46

T or F: 5-10% of patients with history of allergic rxns to penicillin will have the same rxn when given again

Answer 46

True