V 1 Antibacterial lactams

Question 1

Penicillin G, V Mechanisms of action

Answer 1

Bind penicillin-binding proteins (transpeptidases)
Block transpeptidase cross-linking of peptidoglycan in cell wall
Activate autolytic enzymes

Question 2

Penicillin G, V Clinical use

Answer 2

Mostly used for gram-positive organisms (S. pneumoniae, S. pyogenes, Actinomyces)
Also used for gram-negative cocci (mainly N. meningitidis)
Spirochetes (namely T. pallidum)
Bactericidal for gram-positive cocci, gram-positive rods, gram-negative cocci, and spirochetes
Penicillinase sensitive, thus narrow spectrum

Question 3

What is Benzathin penicillin

Answer 3

Long acting type, Thick suspension
Effective on Tertiary syphilis
IM, half life of 2 weeks (Respratory form)

Question 4

Penicillin G, V Toxicity

Answer 4

Hypersensitivity reactions: 5-7% of I-IV HS reactions

Hemolytic anemia

Question 5

Penicillin G, V Resistance

Answer 5

Penicillinase in bacteria (a type of β-lactamase) cleaves β-lactam ring

Question 6

Treatment of Streptococcus agalactiae

Answer 6

ampicillin with an aminoglycoside or a cephalosporin

Question 7

Treatment of Streptococcus pyogenes

Answer 7

Beta lactam drugs

Macrolides are used in the case of penicillin allergy.

Question 8

Treatment of Pneumoccoci

Answer 8

Bacterial pneumonia–macrolides

Adult meningitis—Ceftriaxone or cefotaxime
Vancomycin is added if penicillin- resistant S. pneumoniae has been reported in the community

Otitis media and sinusitis in children–amoxicillin, erythromycin for allergic individuals

Question 9

Treatment of Viridans Streptococci (S. sanguis, S. mutans)

Answer 9

Penicillin G with aminoglycosides for endocarditis

Question 10

Treatment of Clostridium tetani

Answer 10

Hyperimmune human globulin (TIG) to neutralize toxin plus metronidazole or penicillin
Spasmolytic drugs (diazepam); debride; delay closure

Question 11

Treatment of Clostridium perfringens

Answer 11

Gangrene: Debridement, delayed closure, clindamycin and penicillin, hyperbaric chamber

Food poisoning: Self-limiting

Question 12

Treatment of Actinomyces israelii

Answer 12

ampicillin or penicillin G and surgical drainage

Question 13

Treatment of Treponema pallidum

Answer 13

Benzathine penicillin (long-acting form) for primary and secondary syphilis(no resistance to penicillin)

Penicillin G for congenital and late syphilis

Jarisch-Herxheimer reaction in treatment of syphilis

Question 14

Treatment of Leptospira interrogans

Answer 14

penicillin G or doxycycline

Question 15

Amoxicillin, ampicillin Mechanisms of action

Answer 15

Same as penicillin, Wider spectrum, changed solubility thus enter porines and reach cell wall of Gram -
penicillinase sensitive
Also combine with clavulanic acid to protect against destruction by β-lactamase

Question 16

Amoxicillin Features

Answer 16

AmOxicillin has greater Oral bioavailability

than ampicillin

Question 17

Ampicillin features

Answer 17

ampicillin undergoes enterohepatic cycling, but excreted by the kidney

Question 18

Amoxicillin, ampicillin Clinical use

Answer 18

H. influenzae, H. pylori (amoxicillin), E. coli, Proteus mirabilis, Salmonella, Shigella
Borrelia burgdoferi (amoxicillin)
Listeria monocytogenes (ampicillin)
Enterococci

Question 19

Amoxicillin, ampicillin Toxicity

Answer 19

Hypersensitivity reactions
rash
pseudomembranous colitis

Question 20

Amoxicillin, ampicillin Resistance

Answer 20

Penicillinase in bacteria (a type of β-lactamase) cleaves β-lactam ring

Question 21

Dicloxacillin, nafcillin, oxacillin Mechanism

Answer 21

Very narrow spectrum

penicillinase resistant because bulky R group blocks access of β-lactamase to β-lactam ring

Question 22

Nafcillin, oxacillin pharmacokinetics

Answer 22

Nafcillin and oxacillin eliminated largely in bile

Question 23

Dicloxacillin, nafcillin, oxacillin Clinical use

Answer 23

S. aureus (except MRSA: resistant )

Question 24

Dicloxacillin, nafcillin, oxacillin Toxicity

Answer 24

Hypersensitivity reactions
Interstitial nephritis (methicillin)

Question 25

Dicloxacillin, nafcillin, oxacillin Resistance

Answer 25

because of altered penicillin-binding protein target site

Question 26

Treatment of Enterococcus faecalis/faecium

Answer 26

Some vancomycin-resistant strains of Enterococcus faecium or E. faecalis have no reliably effective treatment In general for low-level resistance, use ampicillin+gentamicin, or streptomycin

Question 27

Treatment of Listeria monocytogenes

Answer 27

ampicillin with gentamicin added for imrnunocompromised patients

Question 28

Treatment of Neisseria meningitidis

Answer 28

Neonates/infants: ampicillin and cefotaxime | Older infants, children, and adults: cefotaxime or ceftriaxone with or without vancomycin

Question 29

Treatment of Salmonella enterica Subspecies Other Than typhi

Answer 29

For gastroenteritis self-limiting, antibiotics are contraindicated For invasive disease, ampicillin, third-generation Cephalosporins, fluoroquinolones, or TMP-SMX

Question 30

Treatment of Clostridium botulinum wound

Answer 30

Amoxicillin and antitoxin respiratory support

Question 31

Treatment of Moraxella catarrhalis

Answer 31

Drug resistance is a problem; most strains produce a β-lactamase Amoxicillin + clavulanate, second or third generation cephalosporin or TMP-SMX

Question 32

Treatment of Helicobacter pylori

Answer 32

Myriad of regimens Omeprazole + amoxicillin + clarithromycin is one example of triple therapy - Treat for 1 0-14 days Quadruple therapy is used in areas where clarithromycin resistance is more than 1 5%, e.g., PPI + bismuth + 2 antibiotics (metronidazole + tetracycline)

Question 33

Treatment of Pasteurella multocida

Answer 33

Amoxicillin/clavulanate for cat bites | Resistant to macrolides

Question 34

Treatment of Borrelia burgdorferi

Answer 34

Doxycycline, amoxicillin, or azithromycin/clarithromycin (primary) Ceftriaxone for secondary Doxycycline or ceftriaxone for arthritis

Question 35

Treatment of Staphylococcus aureus

Answer 35

Gastroenteritis is self-limiting Nafcillin/oxacillin are drugs of choice because of widespread antibiotic resistance For methicillin-resistant Staphylococcus aureus (MRSA): vancomycin For vancomycin-resistant Staphylococcus aureus (VRSA) or vancomycin intermediate S. aureus (VISA): quinupristin/dalfopristin

Question 36

Piperacillin, ticarcillin, azlocillin, carbenicillin mechanism

Answer 36

Extended spectrum

Question 37

Piperacillin, ticarcillin, azlocillin, carbenicillin clinical use

Answer 37

Pseudomonas spp. and gram-negative rods susceptible to penicillinase, use with β-lactamase inhibitors

Question 38

Piperacillin, ticarcillin, azlocillin, carbenicillin toxicity

Answer 38

Hypersensitivity reactions

Question 39

β-lactamase inhibitors mechanism

Answer 39

Include Clavulanic Acid, Sulbactam, Tazobactam suicide inhibitors, irreversibly inhibit enzyme Often added to penicillin antibiotics to protect the antibiotic from destruction by β-lactamase (penicillinase)

Question 40

Treatment of pseudomonas

Answer 40

antipseudomonal penicillin (Piperacillin, ticarcillin, azlocillin, carbenicillin) + an aminoglycoside

Question 41

Penicillin pharmacokinetics

Answer 41

Most are eliminated via active tubular secretion with secretion blocked by probenecid dose reduction needed only in major renal dysfunction

Question 42

DOCs in penicillin hypersensitivities

Answer 42

Gram + use macrolide Gram - use Aztreonam