2. DEFINITION:
The cephalosporins are a class of β-lactam
antibiotics originally derived from
the fungus Acremonium chrysogenum, which
was previously known as "Cephalosporium".

4. STRUCTURAL SIMILARITIES BETWEEN
BETA-LACTAM ANTIBIOTICS
 Cephalosporins are a class of semisynthetic
antimicrobial drugs related to the structure and
activity of penicillin.
 As with many antibiotics, cephalosporins were
discovered from natural sources
 Thirty-two different cephalosporin compounds
have been developed since the initial isolation
of cephalosporin C off the coast of Sardinia in
1948.

5.  Subcategorization of cephalosporins into four
different generations was based on their
development by industry.
 However, in general, each subsequent
generation has a broader spectrum of activity
against gram-negative organisms while
maintaining or losing its activity against gram-
positive organisms.

6.  Beta-lactam antibiotics include penicillins,
cephalosporins, carbapenems,
monobactams, and beta-lactam/beta-
lactamase inhibitors.
 These compounds all possess a
characteristic betalactam ring.
 When the beta-lactam ring is fused to a 5-
membered thiazolidine ring, or penam,
the drug is classified as a penicillin
 When fused to a 6-membered
dihydrothiazine ring, or cephem, it is
classified as a cephalosporin

8.  Although both penicillins and cephalosporins
may incorporate different salt forms at the ester
binding site, penicillins have only one side
chain (6-position) while cephalosporins have
two side chains (7- and 3-position).
 The side chains differentiate the activity and
metabolic parameters of individual drugs within
each class.
 Substitution at the 6-position side chain of
penicillins generally results in increased
potency. With cephalosporins, substitutions at
the 7-position side chain alter the microbiologic
activity of the drug.

9.  Modifying cephalosporin molecules at the 3-
position predominately affects changes in
pharmacokinetic parameters, particularly drug
metabolism.
 The penicillin 6-position and cephalosporin 7-
position side chains with an acylamino structure
have demonstrated parallel function.

12. Generatio
n
Organisms
Covered
Comments
First
Generation
• Primarily cover gram positive
organisms: methicillin-sensitive
S. aureus, group A strep
• Some gram negative coverage:
E. coli, Klebsiella species, P.
mirabilis
• Poor anaerobic coverage
•Increased risk of cross-
reactivity in penicillin-
allergic patients in
comparison with other
cephalosporins
Second
Generation
• Maintain gram positive
coverage similar to first
generation agents. Cefuroxime
and cefprozil cover S.
pneumoniae.
•Enhanced coverage of gram
negative organisms: H.
influenza, M. catarrhalis,
Neisseria species
• Some anaerobic coverage.
Cefoxitin and cefotetan cover B.
fragilis.
•Second-generation
agents include both
cephalosporins (cefaclor,
cefprozil, cefuroxime) and
cephamycins (cefotetan,
cefoxitin).
Cephamycins do not have
adequate gram positive
coverage to treat
respiratory infections.
Cefuroxime, etc. does not

13. Generatio
n
Organisms
Covered
Comments
Third
Generatio
n
• Maintain varying degrees of
gram positive coverage,
except for ceftazidime.
Cefotaxime and ceftriaxone
have increased potency
against penicillin-resistant
pneumococci compared with
first- and second-generation
agents.
• Enhanced coverage of gram
negative organisms compared
to first- and second-generation
agents: Enterobacteriaceae
(e.g., Citrobacter, Enterobacter,
Salmonella, Serratia species),
E. coli, Klebsiella species, P.
mirabilis, etc. However,
Enterobacter is often resistant.
• Ceftazidime covers P.
•Inactivated by AmpC
beta-lactamases,
extendedspectrum
beta-lactamases
(ESBLs), and
carbapenemases
(KPCs).
•Ceftazidime, which
has a different
spectrum activity than
other third-generation
cephalosporins, is
structurally similar to
aztreonam.

14. Generatio
n
Organisms
Covered
comments
Fourth
Generatio
n
•Broad coverage of gram positive
and gram negative organisms.
•Coverage of Pseudomonas
similar to ceftazidime. Coverage of
S. pneumonia similar to
ceftriaxone.
• Some anaerobic coverage. No
coverage of B. fragilis.
•No oral agents currently
available
•Less susceptible to
inactivation by AmpC
betalactamases than
second- or third-
generation agents, so
better against Citrobacter
and Enterobacte
Fifth
Generation
(MRSAactive
)
•Enhanced coverage of gram
positive organisms: MRSA, S.
pneumonia, and E. faecalis
• Similar gram negative coverage
to third- and fourth-generation
agents. Ceftaroline does not cover
Pseudomonas.
• Limited anaerobic activity.
•No oral agents currently
available

17.  Beta-lactam antibiotics make up 40% of total
prescriptions of antibiotics in the outpatient setting
(amoxicillin most commonly prescribed drug)
 Cephalosporins make up 14% of total outpatient
antibiotic prescriptions accounting for over 50 million
prescriptions per year
 Cephalosporin most commonly used to treat outpatient
indications of pneumonia, skin and soft tissue
infections, sinusitis, urinary tract infections, otitis
 Inpatients setting most common diagnosis
associated with billing for a cephalosporin is
pneumonia1

20. PELVIC INFLAMMATORY DISEASE
BACTERIAL SEPTICEMIA
BONE & JOINT INFECTIONS
• MENINGITIS
• INTRA ABDOMINL INFECTIONS
• SURGICAL PROPHYLAXIS

22. Which is more in ist gen
Slight in 2nd gen
Not seen in 3rd gen