Small Animal Clinical Pharmacology - CYF MEDICAL DISTRIBUTION

CHAPTER 8 ANTIBACTERIAL DRUGS
Table 8.5 Classification and spectrum of activity of cephalosporins
Generation Drugs Spectrum
First-generation
Second-generation
(all parenteral)
Third-generation
Third-generation antipseudomonal
(all parenteral)
Fourth-generation
(all parenteral)
Parenteral
Cefacetrile
Cephalothin
Cefapirin
Cefazolin
Cefradine
Oral
Cefadroxil
Cefalexin
Cefaloglycin
Cefradine
Ophthalmic
Cefalonium
Cefaclor
Cefamandole
Cefotetan
Cefoxitin
Cefuroxime
Parenteral
Cefmenoxime
Cefotaxime cefquinome
Ceftiofur
Ceftizoxime
Ceftazidime
Ceftriaxone
Cefovecin
Latamoxef
Oral
Cefetamet
Cefixime
Cefpodoxime proxetil
Cefoperazone
Cefsulodin
Ceftazidime
Cefepime
Cefpirome
The antibacterial spectrum of the first-generation
cephalosporins is similar for all drugs within this group.
Their only major advantages over aminopenicillins are their
excellent activity against penicillinase-producing
Staphylococcus and generally greater activity against
Pasteurella
• Good activity against Gram-positive bacteria including
β-lactamase producing Staphylococcus
• Methicillin-resistant Staphylococcus are resistant
• Moderate activity against Gram-negative aerobes
• Resistant bacteria of clinical importance include
Bordetella, Campylobacter, Pseudomonas aeruginosa
and Rhodococcus equi
• Acquired resistance common among Gram-negative
bacteria, particularly Enterobacteriaceae, but rare in
Gram-positive bacteria
• Activity against obligate anaerobes unpredictable and
less than for most penicillins
Moderate Gram-positive and Gram-negative activity
• Moderately active against Gram-positive bacteria
• Broader activity against Gram-negative bacteria than
first-generation cephalosporins but not Pseudomonas
aeruginosa
• Most of the group have only moderate activity against
obligate anaerobes except cefoxitin which has excellent
activity
Decreased Gram-positive but increased Gram-negative
activity
• Good activity against many Gram-positive bacteria
including Streptococcus but not Enterobacter
• The parenteral drugs have moderate–good activity
against Staphylococcus but oral agents are largely
inactive
• Susceptible Gram-negative bacteria include
Escherichia, Klebsiella, Proteus, Pasteurella,
Haemophilus, Actinobacillus, Salmonella
• Activity against Proteus and Pseudomonas varies
between drugs
• Variable activity against obligate anaerobes –
Clostridium and Fusobacterium are susceptible but
Bacteroides are often resistant to some but not all
drugs (e.g. cefovecin has good activity)
• High activity against Pseudomonas aeruginosa
• Otherwise generally less active than other thirdgeneration
drugs
Increased Gram-positive and Gram-negative activity
• High activity against Enterobacteriaceae
• Moderate activity against Pseudomonas aeruginosa
• Enhanced activity against Staphylococcus
• Enterococcus resistant
• Variable resistance amongst obligate anaerobes –
Clostridium perfringens susceptible, Bacteroides and
Clostridium difficile resistant
● Ceftriaxone’s long half-life, good CNS penetration
and activity against Borrelia burgdorferei have made
it a potential choice for treating Lyme disease.
● There are currently no indications for the use of
ceftiofur in small animals, although it is used increasingly
in large animal practice because of its zero drug
withdrawal time. It is used extensively to treat acute
undifferentiated bovine pneumonia, neonatal septicemia
in foals, respiratory and systemic infections in
swine and to control Escherichia infections in poultry.
166