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4.2 Parenteral cephalosporins

According to the Paul Ehrlich Society for Chemotherapy (1), the parenteral cephalosporins have been classified into five groups, according to their spectrum of activity (Table 19).

Group 1 cephalosporins (cefazolin, cefazedone) are very active against streptococci and staphylococci (penicillin G-resistant strains included). They have only weak activity against Gram-negative microorganisms. Like all cephalosporins, cefazolin is not active against enterococci and MRSA and methicillin-resistant coagulase-negative staphylococci (MRSE).

Compared with Group 1 cephalosporins, Group 2 cephalosporins, e.g. cefuroxime, cefotiame and cefamandole, exhibit a markedly improved activity against Gram-negative pathogens and maintain high activity against staphylococci.

Group 3a cephalosporins have high activity against Gram-negatives and less activity against staphylococci. They differ mainly in their pharmacokinetic characteristics.

Group 3b cephalosporins, e.g. ceftazidime, cefepime, cefoperazone and cefpirome, have added high anti-Pseudomonas activity. However, the activity of cefoperazone against P. aeruginosa is markedly inferior to that of the other substances of this group.

Cefsulodine has a special position among Group 4 cephalosporins with its therapeutic relevance limited to P. aeruginosa.

The Group 5 cephalosporins are characterized by their anti-anaerobic activity. These cephalosporins have superior activity against Gram-negative bacteria compared with Group 1 and 2 cephalosporins, but most of them are weaker than Group 3 drugs. At present, cefoxitin is the only drug of that group available on the market in some countries.

Table 20: Classification of parenteral cephalosporins according to the Paul Ehrlich Society for Chemotherapy (2)

Generic names

Features of the group

Group 1

Cefazolin

• Active against Gram-positive and partly also against Gram-

(1st generation)

Cefazedone

negative bacteria

•Stable against staphylococcal penicillinases

• Unstable against (3-lactamases of Gram-negative bacteria

Group 2

Cefuroxime

•Activity against Gram-positive bacteria good, but weaker

(2nd generation)

Cefotiame

than Group 1

Cefamandole

•Activity against Gram-negative bacteria superior to that of Group 1

• Stable against staphylococcal penicillinases

• Limited stability against p-lactamases of Gram-negative bacteria

Group 3a

Cefotaxime

•Activity against Gram-negative bacteria clearly superior to that

(3rd generation)

Ceftriaxone

of Groups 1 and 2

Ceftizoxime

• Stable against numerous p-lactamases of Gram-negative bacteria

Cefmenoxime

• Microbiologically less active against staphylococci

Cefodizime

Group 3b

Ceftazidime

• Spectrum of antibacterial activity similar to that of Group 3a

(3rd generation)

Cefepime

•Additional activity against Pseudomonas aeruginosa

Cefpirome

Cefoperazone

Group 4

Cefsulodin

• Narrow antibacterial spectrum

• Only activity against P. aeruginosa relevant therapeutically

Group 5

Cefoxitin*

•Active against anaerobe bacteria

(*2nd and °3rd

Cefotetan0

• Activity against Gram-negative bacteria superior to that of

generation)

Flomoxef

Group 2, but inferior to that of Group 3a/b

• Activity against staphylococci unsatisfactory

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