L23: Cephalosporins Flashcards
Cefazolin, Cephelexin, and Cefadroxil belong to:
A. First Generation Cephalosporins
B. Second Generation Cephalosporins
C. Third Generation Cephalosporins
A. First Generation
Fedoxitin, Cefuroxime, and Cefotetan are:
A. First Generation Cephalosporins
B. Second Generation Cephalosporins
C. Third Generation Cephalosporins
B. Second Generation
Ceftriaxone, Ceftazidime, Cefixime, and Ceftazidime + Avibactam belong to which group?
A. 1st gen cephalosporins
B. 2nd gen cephalosporins
C. 3rd gen cephalosporins
C. 3rd gen cephalosporins
Cefepime is a ____ generation cephalosporin while Cetaroline fosamil, as well as ceftolozane + tazobactam are ___ a generation cephalosporin
- 4th generation
- 5th generation
True or False: 4th and 5th generation cephalosporins are only administered via IM
False - only administered via IV
Cephalosporins first isolated from ____
Acremonium (Cephalosporium)
What is the MOA used by cephalosporins?
Bind PBP’s and prevent wall cross-links
None of the cephalosporins have activity against ORSA, except a 5th generation cephalosporin known as….
A. Cefepime
B. Cetaroline fosamil
C. Ceftriaxone
D. Ceftazidime
E. Cefixime
B. Cetaroline fosamil
True or False: Gram (-) efficacy decreases in subsequent generations of cephalosporins, often with increasing gram (+) efficacy
False – Gram (+) efficacy INCREASES in subsequent generations of cephalosporins, often with DECREASING gram (+) efficacy
True or False: First generation cephalosporins are reserved for serious nosocomial infections
False - LATER generations are reserved for serious nosocomial infections
R1 vs. R2???
R1: anti-bacterial activity changes
R2: metabolism and PK changes
True or False: The later the generation of cephalosporins, the more gram (-) activity and broad spectrum
True
Why are cephalosporin generations 1-4 “LAME”
No activity against
- Listeria
- Atypicals
- MRSA
- Enterococci
What feature do cephalosporins share with penicillin? Exception?
1) Short 1/2 life
Exception: Ceftriaxone
Cephalosporins have adequate penetration into most tissues, but its penetration into
CNS depends on generation.
Which generations do NOT typically enter CNS, even with
inflamed meninges??
1st and 2nd gen
Which 2nd generation cephalosporin enters ocular fluids and CNS?
Cefuroxime
Which three 3rd generation cephalosporins enter CNS?
Ceftriaxone
Cefotaxime
Ceftazidime
Which 4th generation cephalosporins enter the CNS?
Cefepime
True or False: Like penicillins, nearly all of the cephalosporins are cleared by the kidney, so dosing adjustments
may be necessary for patients with renal deficiencies
True
3rd generation ceftriaxone
___ extends circulating time of cephalosporins
Probenacid
Although there’s only 5-10% frequency of cross-allergy with penicillins, ____ are contraindicated in those with previous serious
reaction to penicillins
cephalosporins
____ are a major source of cephalosporin resistance
Lactamases
Due to ___ ___, cephalosporins are generally more
resistant to lactamases compared to penicillins
steric factors
___ generation cephalosporins are increasingly stable to
lactamases, compared to ___ generations
A. earlier; later
B. later; earlier
B. later; earlier
True or False: 3rd generation cephalosporins are less susceptible to Gram (-) lactamases
True
Although 4th generation cephalosporins are even more stable than 3rd, they are still susceptible to
____ and ____
KPC (carbapenemase)
metallo-β-lactamases
Altered ___ with low affinity for beta lactams is important resistance mode for cephalosporins
PBPs
__ generation cephalosporins are good for routine
infections caused by gram positive cocci
A. First
B. Second
C. Third
D. Fourth
E. Fifth
A. First
True or False: In gram positive organisms that remain sensitive, 1st gen > 2nd and 3rd gens
True
___ is a first generation cephalosporin that is injectable only – choice for surgery prophylaxis
Cefazolin
Which four gram (-) enterics can be treated with 1st generation cephalosporins? (Hint: PECK)
P. mirabilis
E. coli
Klebsiella pneumoniae
_____ is now the only parenteral 1st gen cephalosporin
available in the US
Cefazolin
Which three 1st generation cephalosporins are orally available?
Cephalexin, cefadroxil, or cephradine
Uses for 1st gen cephalosporins?
- Mild ear infection
- UTI
- Pneumonia
- Endocarditis
- Throat infection
- Cellulitis, abscess, (polymicrobial infections)
Orally available 1st generation cephalosporins are poorly active against penicillin-resistant
pneumococci, such as ____
P. aeruginosa
How do 2nd generation cephalosporins compare to 1st gen?
2nd generations are better against Gram (-)
organisms (e.g. H. influenzae, Moraxella
catarrhalis), but sacrifices some Gram (+) efficacy
Which two 2nd generation cephalosporins are effective against anaerobes, including
B. fragilis?
1) Cefoxitin
2) Cefotetan
___ is a 2nd generation cephalosporin that has oral availability
Cefuroxime
Unlike most 2nd gen, _____ has good CNS penetration, but inferior to 3rd generation for meningitis
Cefuroxime
Clinical uses of Cefuroxime?
- Sinusitis
- Otitis media
- Community acquired
pneumonia
Which pathogens does Cefuroxime (oral 2nd gen cephalosporin) have activity against?
S. pneumoniae
H. influenzae
M. catarrhalis
P. pyogenes
K. pneumoniae
True or False: Cephamycins are notable for activity against Bacteroides anaerobes
True
Which two 2nd gen cephalosporins are injectable only and used for anaerobic infections?
Cefoxitin
Cefotetan
____, a 2nd gen cephalosporin, is the choice for prophylaxis in surgery of abdominal and pelvic cavities
A. Cefoxitin
B. Cefotetan
A. Cefoxitin
True or False: For infections outside of the abdominal and pelvic areas, cephamycins have MANY advantages over the
1st generation cephalosporins
False - for infections outside of the abdominal and pelvic areas, cephamycins have NO advantages over the
1st generation cephalosporins
True or False: 2nd gen cephalosporins are better than 3rd generation for treating gram (-) pathogens
False - 3rd generation cephalosporins are better than 2nd generations for treating gram negative infections
True or False: 3rd gen cephalosporins are stable
to the beta-lactamases produced by Neisseria, H.
influenzae, but are ineffective against gram-positives
True
Which two 3rd gen cephalosporins can get into the CNS easily, thereby treat meningitis?
Ceftriaxone
Ceftazidime
____ is a good 3rd generation cephalosporin that is good for treating penicillin-resistant Strep
Pneumoniae
A. Ceftriaxone
B. Ceftazidime
A. Ceftriaxone
True or False: Enterobacter becomes resistant to 3rd gen cephs
True
Sepsis, UTI, infections of respiratory tract, skin, bone/joints can be best treated with which generation of cephalosporins?
A. First
B. Second
C. Third
D. Fourth
C. Third
3rd Generation Ceftazidime is particularly useful
against _____
A. E. coli
B. P. aeruginosa
C. S. aureus
D. S. pneumo
B. P. aeruginosa
Which generation cephalosporin is stable to the beta-lactamases produced by Pseudomonas aeruginosa strains resistant to the anti-pseudomonal penicillins?
A. First generation
B. Second generation
C. Third generation
D. Fourth generation
C. Third generation
Ceftazidime (3rd gen cephalosporin) is good for meningitis due to pseudomonas, but it is ineffective against _____
A. Gram (+)
B. Gram (-)
A. Gram (+)
Cefoperazone is similar to ceftazidime, but inferior. Why?
Greater vulnerability to lactamases, and adverse effects including anticoagulation
Properties of Ceftriaxone?
- Extensive billary clearance (no dose adjustments for renal insufficiency)
- Resistant to some B-lactamases – but vulnerable to ESBL’s
- Good at penetrating CSF/peipheral fluids
What is the recommended therapy for Neisseria
gonorrhoeae, even penicillin-resistant forms?
Ceftriaxone IM
True or False: Oral cefixime also effective for N. gonorrheae
True
What are 3 conditions that can be treated with Ceftraxione?
- N. gonorrhoeae (even penicillin resistant forms!)
- S. pneumo
- Neuro complications from Lyme (B. burgdorferi)
Limitations of Ceftriaxone?
- Poor activity against P. aeruginosa
- No activity against ORSA (LAME)
- Not effective against Enterobacter
- Precipitation toxicities