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2nd Year 2nd Term > MT6314 ANTIMICROBIALS BETA LACTAMS > Flashcards

MT6314 ANTIMICROBIALS BETA LACTAMS Flashcards

1
Q

Drugs that inhibit the growth/replication, or kill microrganisms

A

Antimicrobials

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2
Q

Antimicrobials include what kind of drugs based on their target molecule?

A

̶ Antibacterial
̶ Antifungal
̶ Antiviral
̶ Anti-protozoal
̶ Anti parasitic

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3
Q

Antimicrobials are under that kind of drugs?

A

chemotherapeutic drugs

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4
Q

2 kinds of bacteria?

A

Gram-positive
Gram-negative

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5
Q

Bacterial cell wall synthesis inhibitors include?

A

Penicillins
Cephalosporins
Miscellaneous

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6
Q

2 kinds of penicillins?

A

Narrow spectrum
Wider spectrum

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7
Q

2 kinds of cephalosporins?

A

Narrow spectrum
Wider spectrum

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8
Q

Kinds of miscellaneous bacterial synthesis inhibitors?

A

Carbapenems
Aztreonam
Vancomycin

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9
Q

First to suggest that a Penicillium mold (now known as Penicillium chrysogenum) must secrete an antibacterial substance

A

Sir Alexander Fleming

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10
Q

Sir Alexander Fleming suggested that _____ must secrete _________

A

Penicillium mold (Penicillium chrysogenum)
antibacterial substance

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11
Q

First to concentrate the active substance involved, which he named penicillin, in 1928.

A

Sir Alexander Fleming

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12
Q

Penicillins are derivates of?

A

6-aminopenicillamic acid

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13
Q

Penicillins contain what structure?

A

beta lactam ring structure

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14
Q

What determines the drug’s stability to enzymatic or acidic hydrolysis?

A

Nature of the R group

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15
Q

The nature of the R group also affects?

A

Antibacterial spectrum

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16
Q

The beta-lactam ring is the site of?

A

Hydrolysis by bacterial penicillinase or by acid

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17
Q

Penicillin basic structure includes?

A
  1. Thiazolidine ring (A)
  2. β-lactam ring (B) that carries a secondary amino group (RNH–)
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18
Q

R group penicillins include?

A

Penicillin G
Penicillin V
Oxacillin
Dicloxacillin
Nafcillin
Ampicillin
Amoxicillin
Piperacillin

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19
Q

WHAT KIND OF B-LACTAM ANTIBIOTICS: Ampicillin

A

1st gen cephalosporin

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20
Q

WHAT KIND OF B-LACTAM ANTIBIOTICS: Cefazolin

A

2nd gen cephalosporin

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21
Q

WHAT KIND OF B-LACTAM ANTIBIOTICS: Cefaclor

A

3rd gen cephalosporin

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22
Q

WHAT KIND OF B-LACTAM ANTIBIOTICS: Aztreonam

A

Monobactams

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23
Q

WHAT KIND OF B-LACTAM ANTIBIOTICS: Biapenem

A

Carbapenems

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24
Q

WHAT KIND OF B-LACTAM ANTIBIOTICS: Amoxicillin

A

Penicillins

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25
Q

WHAT KIND OF B-LACTAM ANTIBIOTICS: Ertapenem

A

Carbapenems

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26
Q

WHAT KIND OF B-LACTAM ANTIBIOTICS: Doripenem

A

Carbapenems

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27
Q

WHAT KIND OF B-LACTAM ANTIBIOTICS: Imipenem

A

Carbapenems

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28
Q

WHAT KIND OF B-LACTAM ANTIBIOTICS: Panipenem

A

Carbapenems

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29
Q

WHAT KIND OF B-LACTAM ANTIBIOTICS: Tigemonam

A

Monobactam

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30
Q

WHAT KIND OF B-LACTAM ANTIBIOTICS: Carumonam

A

Monobactam

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31
Q

WHAT KIND OF B-LACTAM ANTIBIOTICS: Nocardicin A

A

Monobactam

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32
Q

Pharmacokinetics of antimicrobials vary in?

A

Vary in their oral availability

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33
Q

Penicillins are polar or non-polar?

A

Polar

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34
Q

T or F: Penicillins are metabolized extensively

A

F, not metabolized extensively

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35
Q

How is penicillin excreted and it is inhibited by?

A

̶ Excreted unchaned in urine
̶ Inhibited by Probenecid

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36
Q

When do antimicrobials cross the BBB?

A

when meninges are inflamed (MENINGITIS)

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37
Q

How should antimicrobials be given usually?

A

on an empty stomach; except Amoxicillin

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38
Q

MOA of antimicrobials?

A

*Bactericidal drugs
*Inhibit cell wall synthesis
1. Binds to PBP
2. Inhibits transpeptidation
3. Activation of autolytic enzymes

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39
Q

Antimicrobials inhibit what action of bacterial cell wall synthesis?

A

transpeptidation reaction

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40
Q

What is the final step of the synthesis of the peptidoglycan?

A

Cross linking of PEP side chains

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41
Q

The cross linking of PEP side chains is blocked by?

A

Penicillin

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42
Q

Antimicrobial resistance is brought about by?

A

Hydrolysis of the β -lactam ring by bacterial β -lactamases
Modification of PBP
Changes in membrane permeability

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43
Q

Clinical uses of penicillins?

A

*Narrow spectrum penicillinase susceptible agents
*Very Narrow spectrum penicillinase resistant agents – against Staphylococcus aureus
*Wider spectrum penicillinase susceptible drugs

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44
Q

limited spectrum; susceptible to β-lactamases

A

Penicillin G

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45
Q

Penicillin G is susceptible to?

A

β-lactamases

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46
Q

Penicillin G is used for?

A

streptotocci, meningococci, gram-positive bacilli, spirochetes

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47
Q

What is the first line drug for syphilis?

A

Benzathine Penicillin G

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48
Q

Benzathine Penicillin G is given how?

A

IM

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49
Q

Narrow spectrum penicillinase susceptible agents include what drugs?

A

Pen G
Pen V

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50
Q

Very Narrow spectrum penicillinase resistant agents – against Staphylococcus aureus, include what drugs?

A

Methicillin
Oxacillin
Cloxacillin (Dicloxacillin)

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51
Q

Wider spectrum penicillinase susceptible drugs include?

A

Ampicillin and Amoxicllin
Piperacillin and Ticarcillin

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52
Q

Wider spectrum than Pen G

A

Ampicillin and Amoxicllin

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53
Q

Ampicillin and Amoxicllin are enhanced when used with?

A

penicillinases (BLIC or beta-lactam-inhibitor combination)

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54
Q

Piperacillin and Ticarcillin have enhanced activity against?

A

gram-negative (Pseudomonas, Enterobacter, Klebsiella)

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55
Q

Piperacillin and Ticarcillin is usually combined with?

A

penicillinase inhibitors

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56
Q

Toxicity of antimicrobials include?

A

Allergy – urticaria, pruritus, fever, joint swelling, anemia, anaphylaxis
GI disturbances : nausea, diarrhea

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57
Q

Toxicity of Methicillin causes?

A

interstitial nephritis

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58
Q

Toxicity of Nafcillin causes?

A

Neutropenia

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59
Q

Toxicity of Ampicillin causes?

A

rash (non-allergic)
pseudomembranous colitis

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60
Q

Resemble β -lactam molecules, but have very weak antibacterial action

A

Beta-Lactamase inhibitors

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61
Q

Beta-Lactamase inhibitors resemble what?

A

β -lactam molecules

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62
Q

T or F: Beta-Lactamase inhibitors have strong antibacterial action

A

F, very weak

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63
Q

Beta-Lactamase inhibitors are combined with what to protect them from?

A

Combined with beta-lactam antibiotics to protect them from β-lactamases

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64
Q

Protection of the Beta-Lactamase inhibitors from β-lactamases subsequently protects them from?

A

inactivation

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65
Q

Beta-lactamase inhibitors are available only in?

A

fixed combinations with specific penicillins and cephalosporins

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66
Q

Cephalosporins are derivatives of?

A

7-aminocephalosporanic acid

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67
Q

T or F: Cephalosporins do not contain a B-lactam structure.

A

F, they contain one

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68
Q

Who isolated Cephalosporin C compound in from the fungus Acremonium?

A

Giuseppe Brotzu

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69
Q

Giuseppe Brotzu isolated ________compound in from the fungus________, previously known as _____________ in 1945.

A

Cephalosporin C
Acremonium
“Cephalosporium”

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70
Q

More stable to many bacterial β–lactamases, has broader spectrum of activity

A

Cephalosporins and Cephamycins

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71
Q

How many sites of attachment do Cephalosporins and Cephamycins have for what groups?

A

2 sites of attachment for various R1 and R2 groups

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72
Q

T or F: Cephalosporins and Cephamycins are more stable compared to other bacterial β–lactamases

A

T

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73
Q

R group at 7-position is R1 or R2?

A

R2

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74
Q

R group at 3-position is R1 or R2?

A

R1

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75
Q

R group at 7-position function?

A

alters antibacterial activity

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76
Q

R group at 3-position function?

A

modifies pharmacokinetic profile

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77
Q

Route of administration of cephalosporins?

A

Most are parenteral/ IV

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78
Q

Major elimination of cephalosporins are by?

A

renal extretion; some with side chains – hepatic metabolism

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79
Q

Which cephalosporins are excreted in the bile?

A

Cefoperazone and ceftriaxone

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80
Q

Do not cross BBB even in inflamed meninges

A

1st and 2nd generation cephalosporins

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81
Q

When cephalosporins bind to the PBP, what occurs?

A

inhibit cell wall synthesis, similar to penicillins

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82
Q

Cephalosporins are?

A

bactericidal

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83
Q

Structural differences render cephalosporins less suseceptible to ____________

A

penicillinases produced by staphylococci

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84
Q

Some organisms are resistant through production of?

A

other beta-lactamases vs cephalosporins

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85
Q

What bacteria is resistant to cephalosporins?

A

MRSA

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86
Q

Clinical Uses of 1st Generation drugs?

A

Cefazolin and cephalexin – against G+ cocci, E coli, K pneumoniae

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87
Q

Clinical Uses of 2nd Generation drugs?

A

̶ Less activity against G+, extended G- overage
̶ Anaerobic coverage : Cefotetan, Cefoxitin
̶ H influenzae, M catarrhalis: Cefamandole, cefuroxime, cefaclor

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88
Q

3rd generation drugs include?

A

Ceftazidime, cefoperazone, cefotaxime

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89
Q

3rd Generation drugs have what kin of clinical use?

A

̶ Increased activity for G-; penetrates BBB (except Cefoperazone and Cefixime)

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90
Q

Drug used against gonococcal urethritis?

A

Ceftriaxone (3rd gen)

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91
Q

Clinical Uses of 4th generation drugs?

A

̶ Cefepime – more resistant to beta lactamases; combines gram positive activity of 1st gen. with wider gram neg. spectrum of 3rd gen.
̶ Ceftaroline – active against MRSA

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92
Q

Toxicity of antimicrobials?

A

Allergy – from rashes to anaphylactic shock
Complete cross reactivity should be assumed

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93
Q

Percentage of cross reactivity between penicillin and cephalosporin is assumed to be?

A

5-10%

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94
Q

First generation cephalosporins are predominantly active against ______, with succeeding generations progressively more active against ______ strains (often with reduced ______ activity except ____ generation, which are extended spectrum agents)

A

Gr(+)’s
Gr(-)
Gr(+)
4th

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95
Q

Cephalosporins are inactive against?

A

Listeria
Atypicals
Methicillin-resistant staphylococcus aureus (MRSA)- except Ceftaroline
Enterococcus

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96
Q

Coverage of 1st generation cephalosporins?

A

Gr(+) cocci, E.coli, K pneumoniae, and Proteus mirabilis

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97
Q

Coverage of 2nd generation cephalosporins?

A

same as 1st gen but with extended Gr(-) activity- Klebsiella, H. influenzae, Bacteroides fragilis, Serratia

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98
Q

Coverage of 3rd generation cephalosporins?

A

Expanded Gram-negative coverage: Citrobacter, serratia, providencia, Pseudomonas (Ceftazidime)

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99
Q

Coverage of 4th generation cephalosporins?

A

Pseudomonas, Enterobacteriaceae , methicillin-susceptible S. aureus, S. pneumoniae., Haemophilus and Neisseria sp.

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100
Q

MOA or drawback of 2nd generation cephalosporins?

A

Not useful against Enterobacter

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101
Q

MOA of 3rd generation cephalosporins?

A

Some able to cross the blood-brain-barrier
Not useful against Enterobacter
No longer commercially available

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102
Q

MOA of 4th generation cephalosporins?

A

Penetrates well into cerebrospinal fluid.
Useful in treatment of Enterobacter infections.

103
Q

WHAT GENERATION DRUGS: Cefazolin, cefadroxil, cephalexin, cephalothin, cephapirin, cephradine

A

1ST

104
Q

WHAT GENERATION DRUGS: Cefaclor, cefamandole, cefonicid, cefuroxime, cefprozil, loracarbef, and ceforanide

A

2ND

105
Q

WHAT GENERATION DRUGS: Cefotaxime, ceftazidime, ceftizoxime, ceftriaxone, cefixime

A

3RD

106
Q

WHAT GENERATION DRUGS: cefpodoxime proxetil, cefdinir, cefditoren pivoxil, ceftibuten, moxalactam, cefoperazone

A

3RD

107
Q

WHAT GENERATION DRUGS: ceftizoxime, moxalactam, cefoperazone

A

3RD BUT NOT COMMERCIALLY AVAILABLE

108
Q

WHAT GENERATION DRUGS: cefepime

A

4th

109
Q

This first-generation parenteral cephalosporin has a longer duration of action and a similar spectrum of action, compared to other first- generation drugs. It penetrates well into bone.

A

Cefazolin

110
Q

This is the prototype of first-generation, oral cephalosporins. Oral administration twice daily is effective against pharyngitis.

A

Cephalexin

111
Q

1st generation drugs examples?

A

Cefazolin
Cefadroxil
Cephalexin

112
Q

This parenteral cephalosporin has a longer half-life than similar agents. It crosses the blood-brain barrier, and it can be used for community- acquired bronchitis or pneumonia in the elderly and for patients who are immunocompromised.

A

Cefuroxime sodium

113
Q

Administered twice daily, this drug is well absorbed and is active against B-lactamase-producing organisms.

A

Cefuroxime axetil

114
Q

2nd generation drugs examples?

A

Cefuroxime sodium
Cefuroxime axetil

115
Q

These are administered orally once daily.

A

Cefdinir
Cefixime

116
Q

This penetrates well into the CSF.

A

Cefotaxime

117
Q

This is active against Pseudomonas aeruginosa.

A

Ceftazidime

118
Q

This drug has the longest half-life of any cephalosporin (6 to 8 hours), which permits once-a-day dosing. High levels of the drug can be achieved in blood and CSF.

A

Ceftriaxone

119
Q

Ceftriaxone is effective against?

A

genital, anal, and pharyngeal penicillin-resistant Neisseria gonorrhoeae.

120
Q

Ceftriaxone is excreted in patients with? And it has good penetration into?

A

renal insufficiency.
good penetration into bone.

121
Q

3rd generation drugs examples?

A

Cefdinir
Cefixime
Cefotaxime
Ceftazidime
Ceftriaxone

122
Q

This is active against Pseudomonas aeruginosa.

A

Cefepime

123
Q

4th generation drugs examples?

A

Cefepime

124
Q

This is active against MRSA,

A

Ceftaroline

125
Q

Advanced generation drugs examples?

A

Ceftaroline

126
Q

Adverse reactions of cephalosporins include?

A
  • Renal: interstitial nephritis and tubular necrosis
  • Hematologic: Hypoprothrombinemia and bleeding disorders (Cefotetan, cefamandole, cefmetazole, and cefoperazone)
  • Others: Local irritation and pain (IM), thrombophlebitis (IV)
127
Q

Resistant to beta-lactamases by some organisms

A

Monobactam - AZTREONAM

128
Q

Aztreonam coverage is limited to?

A

aerobic Gr(-) organisms

129
Q

T or F: Penicillin-allergic patients cannot tolerate aztreonam

A

F, can tolerate without reaction

130
Q

Major toxicity is uncommon and parenteral administration

A

AZTREONAM

131
Q

What is the coverage of carbapenems?

A

Gram-negative rods including P. aeruginosa, Gram-positive organisms, and anaerobes

132
Q

Carbapenems are resistant to?

A

most β –lactamases, ESBL

133
Q

What carbapenems are administered IV?

A

Doripenem, ertapenem, imipenem, and
meropenem

134
Q

Imipenem is combined with what to inhibit what?

A

combined with cilastatin which inhibits dehydropeptidases- enzymes in renal tubules that inhibit imipinem.

135
Q

Carbapenems penetrate what well, except?

A

Penetrate CSF well except ertapenem

136
Q

Excretion of carbapenems are through?

A

renal, adjust dose in renal insufficiency

137
Q

Vancomycin is isolated from?

A

bacterium Amycolatopsis orientalis

138
Q

Coverage of vancomycin?

A

bactericidal against Gram-positive cocci and anaerobes (i.e. Enterococcus faecium); Active against MRSA

139
Q

Similar drug to vancomycin?

A

Teicoplanin

140
Q

MOA of vancomycin?

A

binds to D-Ala-D-Ala terminal of peptidoglycan; inhibits transglycosylation

141
Q

Adverse reactions to vancomycin?

A

red man syndrome

142
Q

Fosfomycin is a _________ inhibitor of ___________

A

Antimetabolite inhibitor of enolpyruvate transferase

143
Q

Fosfomycin inhibits addition of what to what?

A

Inhibits addition of phosphoenolpyruvate to UDP-N-acetylglucosamine

144
Q

Coverage of fosfomycin?

A

gram-positive and gram negative

145
Q

Excretion of fosfomycin?

A

renal, with urinary concentrations exceeding MICs for most urinary tract pathogens

146
Q

Clinical use of fosfomycin?

A

uncomplicated cystitis (UTI)

147
Q

Bacitracin was obtained from?

A

Tracy strain of Bacillus subtilis in 1943.

148
Q

Coverage of Bacitracin?

A

gram-positive microorganisms

149
Q

MOA of Bacitracin?

A

Inhibits cell wall formation by interfering with the lipid carrier that transfers peptidoglycan subunits to the growing cell wall

150
Q

Adverse reactions to Bacitracin include?

A

highly nephrotoxicity when administered systemically

151
Q

Clinical use of Bacitracin include?

A

topical antibiotic

152
Q

Cycloserine is produced by?

A

Streptomyces orchidaceous.

153
Q

MOA of cycloserine?

A

inhibits incorporation of d-alanine into peptidoglycan pentapeptide by inhibiting alanine racemase, which converts l-alanine to d-alanine, and d-alanyl-d-alanine ligase.

154
Q

Pharmacokinetics of Cycloserine?

A

widely distributed in tissues, excreted in urine

155
Q

Clinical use of Cycloserine?

A

treatment of tuberculosis caused by strains of Mycobacterium tuberculosis resistant to first-line agents

156
Q

Adverse reactions to cycloserine include?

A

headaches, tremors, acute psychosis, and convulsions

157
Q

Daptomycin is a fermentation product of?

A

Streptomyces roseosporus

158
Q

Coverage of Daptomycin?

A

vancomycin-resistant strains of enterococci and S aureus (VRE, VRSA)

159
Q

MOA of Daptomycin?

A

depolarization of the cell membrane with potassium efflux and rapid cell death

160
Q

Excretion of Daptomycin?

A

renal

161
Q

Adverse reactions of Daptomycin include?

A

myopathy- monitor creatine phosphokinase levels, allergic pneumonitis in patients receiving prolonged therapy (>2 weeks)

162
Q

What antagonizes Daptomycin?

A

Pulmonary surfactant

163
Q

T or F: Pulmonary surfactant antagonizes daptomycin, and it can be used to treat pneumonia.

A

F, should not be used to treat pneumonia

164
Q

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

A

Bactericidal

165
Q

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

A

Bacteriostatic

166
Q

Drugs with structures containing a beta-lactam ring that must be intact for antimicrobial action

A

Beta-lactam antibiotics

167
Q

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

A

Beta-lactamases

168
Q

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

A

Beta-lactam inhibitors

169
Q

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

A

Minimal inhibitory concentration (MIC)

170
Q

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

A

Penicillin- binding proteins (PBPs)

171
Q

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

A

Peptidoglycan

172
Q

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

A

Selective toxicity

173
Q

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

A

Transpeptidases

174
Q

Microbial resistance includes?

A
  1. Production of antibiotic-inactivating enzymes
  2. Changes in the structure of target receptors
  3. Increased efflux via drug transporters
  4. Decreases in the permeability of microbes’ cellular membrane to antibiotics
175
Q

Strategies of Chemotherapeutic agents?

A
  1. Use of adjunctive agents that can protect against antibiotic inactivation
  2. Use of antibiotic combinations
  3. Introduction of new (and often expensive)
    chemical derivatives of established antibiotics
  4. Efforts to avoid indiscriminate use or misuse of antibiotics
176
Q

Major antibiotics that inhibit cell wall synthesis include?

A
  • Penicillins
  • Cephalosporins
177
Q

B-lactam antibiotics inhibit?

A

cell wall synthesis

178
Q

Drugs that are not as important as beta-lactam drugs include?

A
  • Vancomycin
  • Fosfomycin
  • Bacitracin
179
Q

What is essential for antibacterial activity seen in penicillins?

A

beta-lactam ring structure

180
Q

Subclasses of penicillin have additional chemical substituents that confer differences in?

A
  • Antimicrobial activity
  • Susceptibility to acid and enzymatic hydrolysis
  • Biodisposition
181
Q

Pharmacokinetics of penicillins vary in?

A

resistance to gastric acid, oral bioavailability, and polar compounds (not metabolized extensively)

182
Q

T or F: Penicillins are excreted unchanged in the feces

A

F, unchanged in urine

183
Q

Tubular excretion of penicillins are inhibited by?

A

Probenecid

184
Q

Penicillins partly excreted in bile?

A

Ampicillin and Nafcillin

185
Q

Ampicillin and Nafcillin plasma half-life is how long?

A

30 min to 1 h

186
Q

Procaine and Benzathine Penicillin G are given how?

A

IM

187
Q

Procaine and Benzathine Penicillin G: long or short half lives?

A

Long

188
Q

Procaine and Benzathine Penicillin G can cross?

A

BBB with inflamed meninges

189
Q

MOA of penicillins?

A

Bactericidal

190
Q

How do penicillins inhibit cell wall synthesis?

A
  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
191
Q

If Cross-linked peptidoglycans are damaged, this will result to?

A

cell lysis (bactericidal)

192
Q

Enzymatic hydrolysis of the beta-lactam ring results in the?

A

loss of antibacterial activity

193
Q

Formed by most staphylococci and gram (-)
organisms

A

Beta-lactamases

194
Q

Beta-lactamases are also known as?

A

Penicillinases

195
Q

Beta-lactamases have am major mechanism for?

A

bacterial resistance

196
Q

Inhibitors of this enzymes are used in combination with penicillin to prevent their inactivation include?

A
  • Clavulanic acid
  • Sulbactam
  • Tazobactam
197
Q

Penicillin resistance includes structural changes in?

A

target PBPs and the porin structure of the outer membrane

198
Q

Other mechanisms of bacterial resistance includes?

A
  • Methicillin resistance in staphylococci
  • Penicillin G resistance in pneumococci
199
Q

Narrow-spectrum penicillinase-susceptible
agent that is a prototype, parenteral with a limited spectrum of activity

A

PENICILLIN G

200
Q

PENICILLIN G is susceptible to?

A

beta-lactamases

201
Q

PENICILLIN G is useful against infections caused by?

A
  • Streptococci
  • Meningococci
  • Gram (+) bacilli
  • Spirochetes
    Penicillin-resistant S. pneumoniae (PRSP) strains
202
Q

Some strains resistant to Pen G via production of beta-lactamases

A
  • S. aureus
  • N. gonorrhea
203
Q

Drug of choice for syphilis

A

PENICILLIN G

204
Q

Narrow-spectrum drug given orally for Oropharyngeal infections

A

PENICILLIN V

205
Q

Very-narrow-spectrum penicillinase-resistant agents used as a treatment of known or suspected staphylococcal infections

A

METHICILLIN (prototype), NAFCILLIN, OXACILLIN

206
Q

Has Wider spectrum than pen G, Susceptible to penicillinases

A

AMPICILLIN and AMOXICILLIN

207
Q

Wider spectrum penicillinase-susceptible
agents include?

A

AMPICILLIN and AMOXICILLIN

208
Q

AMPICILLIN and AMOXICILLIN have uses similar to Pen G which include?

A
  • Enterococci - L. monocytogenes
  • E. coli - P. mirabilis
  • H. influenzae - M. catarrhalis
209
Q

Synergistic (1+1=3) with aminoglycosides in enterococcal and listerial infections

A

AMPICILLIN and AMOXICILLIN

210
Q

Wider spectrum penicillinase-susceptible agents include?

A

PIPERACILLIN and TICARCILLIN

211
Q

Used against Pseudomonas, Enterobacter
and Some cases of klebsiella species

A

PIPERACILLIN and TICARCILLIN

212
Q

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

A

Pseudomembranous colitis

213
Q

Cephalosporins with side chains undergo?

A

hepatic metabolism

214
Q

Major elimination of cephalosporins is via?

A

renal tubular excretion

215
Q

What cephalosporins are excreted majorly in the bile and what generation are these?

A

Cefoperazone and ceftriaxone (3rd generation)

216
Q

Which generation cephalosporins do not enter the CSF when the meninges are inflamed?

A

1st- and 2nd-generation

217
Q

Effective against B.fragilis?

A

Cefofetan, cefoxitin

218
Q

Effective against H.influenzae or M.catarrhalis?

A

Cefamandole, cefuroxime, cefaclor

219
Q

3rd generation cephalosporins have the ability to penetrate the blood-brain barrier except?

A

cefoperazone, cefixime

220
Q

3rd generation cephalosporins are effective against?

A

S. marcescens

221
Q

Activity against Pseudomonas

A

Cefoperazone, ceftazidime (3rd gen)

222
Q

Drug of choice for gonorrhea

A

Ceftriaxone (IV) and cefixime

223
Q

Single injection for acute otitis media
As effective as 10 days of amoxicillin

A

Ceftriaxone

224
Q

Cefepime effective against?

A
  • Enterobacter
  • Haemophilus
  • Neisseria
  • Some penicillinase-resistant pneumococci
225
Q

Combines the gram (+) activity of 1st gen
and wider gram (-) spectrum of 3rd gen

A

Cefepime

226
Q

May cause hypoprothrombinemia, and has Disulfiram-like reactions with ethanol

A

Drugs containing a methlythiotetrazole group: Cefamandole, cefoperazone, cefofetan

227
Q

Monobactam that is resistant to beta-lactamases produced by certain gram (-) rods (Klebsiella, Pseudomonas, Serratia)

A

ASTREONAM

228
Q

ASTREONAM is resistant to beta-lactamases produced by certain gram (-) rods which are?

A
  • Klebsiella
  • Pseudomonas
  • Serratia
229
Q

An inhibitor of cell wall synthesis binding to
PBP3

A

ASTREONAM

230
Q

No cross-allergenicity with penicillin

A

ASTREONAM

231
Q

Carbepenems that retain the beta-lactam ring

A

IMIPENEM, MEROPENEM, and ERTAPENEM

232
Q

IMIPENEM, MEROPENEM, and ERTAPENEM are useful against infections caused by?

A

organisms resistant to other antibiotics

233
Q

Rapidly inactivated by renal dehydropep-
tidases I

A

IMIPENEM

234
Q
  • Administered in combination
  • Inhibitor of the enzyme
  • Increases the half-life
  • Inhibits formation of nephrotoxic metabolites
A

Cilastatin

235
Q
  • Similar to imipenem
  • Not metabolized by renal dehydropeptidases
  • Less likely to cause seizure
A

MEROPENEM

236
Q
  • Long half-life
  • Less active against pseudomonas
  • IM injection causes pain and irritation
A

ERTAPENEM

237
Q

Used in fixed combination with certain hydrolyzable penicillins

A

CLAVULANIC ACID, SULBACTAM,
and TAZOBACTAM

238
Q

Plasmid-encoded beta-lactamases include?

A
  • Gonococci
  • Streptococci
  • E. coli
  • H. influenzae
239
Q

Bactericidal glycoprotein which binds to the D-Ala-D-Ala terminal of the nascent peptidoglycan pentapeptide side chain

A

VANCOMYCIN

240
Q

VANCOMYCIN inhibits?

A

transglycosylation, elongation of peptidoglycan chain and cross-linking

241
Q

Due to decreased affinity of the drug to
the binding site there is replacement of D-Ala by D-lactate

A

Vancomycin-resistant enterococci (VRE)
and vancomycin-resistant S. aureus
(VRSA)

242
Q

Drug-resistant gram (+) organisms include?

A
  • MRSA
  • Penicillin-resistant pneumococci
  • C. difficile
243
Q

Not absorbed orally; Maybe given for bacterial enterocolitis

A

VANCOMYCIN

244
Q

Vancomycin dosage modification in patients with?

A

renal impairment

245
Q

Fosfomycin resistance happens via?

A

decreased intracellular accumulation of the drug

246
Q

Antimetabolite inhibitor of cytosolic enolpyruvate transferase that prevents the formation of N- acetylmuramic acid which is essential in peptidoglycan chain formation

A

FOSFOMYCIN

247
Q

In a single dose of Fosfomycin, the drug is less effective than?

A

the 7-day course of treatment with fluoroquinolones

248
Q

What is common in Fosfomycin?

A

Diarrhea

249
Q

Fosfomycin is synergistic with?

A

beta-lactam and quinolones in specific infections

250
Q

Peptide antibiotic that interferes with a late stage in cell wall synthesis in gram (+) organisms

A

BACITRACIN

251
Q

BACITRACIN is limited to ____ use only

A

Topical

252
Q

Antimetabolite that blocks the incorporation of D-Ala into the pentapeptide side chain of the peptidoglycan

A

CYLCOSERINE

253
Q

CYLCOSERINE is only used in?

A

TB caused by organisms resistant to first-line antituberculous drugs

254
Q

CYLCOSERINE is potentially?

A

Potentially neurotoxic causing tremors, seizure and psychosis

2nd Year 2nd Term (38 decks)

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