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The cephalosporins are currently classified into four generations according to their antibacterial spectrum, antibacterial activity, stability to β-lactamase, and nephrotoxicity.

First generation cephalosporin

Main varieties:

Commonly used injections include cefazolin, cefradine, etc. Oral preparations include cefradine, cephalexin and cefadroxil.

Its characteristics are:

1. The effect on Gram-positive bacteria is stronger than that of the second and third generations.

2. The effect on Gram-negative bacilli is weaker than that of the second and third generations.

3. It has certain toxicity to the kidneys.

4. The stability of β-lactamase is worse than that of the second and third generations.

Mainly used:

Infections in the respiratory tract, lungs, pharynx, urethra, skin, and soft tissues caused by sensitive strains of Staphylococcus, Streptococcus, Diphtheria, Klebsiella, and Escherichia coli are required for large doses in the treatment of sepsis and endocarditis.

Cefazolin is often used as a surgical prophylaxis. The antibacterial effects of oral preparations such as cefradine and cephalexin are worse than those of cefazolin, and are mainly suitable for the treatment of mild cases caused by sensitive bacteria.

 

Second generation cephalosporin

Main varieties:

The injections include cefuroxime and cefotiam. The oral preparations include cefaclor, cefuroxime axetil and cefprozil.

Its characteristics are:

1. It has a considerable effect on Gram-positive bacteria and Gram-negative bacteria, and is less effective than Gram-negative bacteria in the third generation. Some varieties are effective against anaerobic bacteria, but not for Pseudomonas aeruginosa.

2. Stable to β-lactamase.

3. Less toxic to the kidneys.

4. Individual varieties such as cefuroxime have a certain amount of penetration into the inflammatory cerebrospinal fluid.

Mainly used:

The effect on Gram-positive bacteria is weaker or similar to that of the first generation, but the antibacterial effect against Gram-negative bacteria is stronger than that of the first generation. The antibacterial spectrum is wider than that of the first generation, and it is also good for Salmonella typhi, Shigella, and Streptococcus. Antibacterial effect. It is mainly used for respiratory tract, urinary tract, biliary tract infection and sepsis, peritonitis caused by sensitive bacteria; the second generation cephalosporin is used in combination with anti-anaerobic drugs for abdominal infection and pelvic infection.

Oral preparations such as cefaclor, cefuroxime axetil, and cefprozil are mainly suitable for mild cases of the above infections. Cefuroxime is also a commonly used preventive drug for perioperative period.

 

Third generation cephalosporin

Main varieties:

The injection varieties were cefotaxime, ceftriaxone, ceftazidime, cefoperazone, etc. The oral varieties were cefixime and cefpodoxime. The oral varieties had no effect on Pseudomonas aeruginosa.

Its characteristics are:

1. The antibacterial spectrum is broad, and it has strong antibacterial effect on various Gram-negative bacilli, but the effect on Gram-positive bacteria is slightly worse than that of the first and second generations.

2. It is stable to lactamase and effective against penicillin-resistant Staphylococcus aureus.

3. It is basically non-toxic to the kidneys.

4. A certain amount of individual species penetrates into the inflammatory cerebrospinal fluid.

Mainly used:

Severe infections of drug-resistant Gram-negative bacilli, such as sepsis caused by drug-resistant bacteria, severe urinary tract infections, biliary tract infections, intra-abdominal infections, Gram-negative bacilli osteomyelitis, pneumonia in hospital infections, and susceptible bacteria Meningitis and so on.

The third-generation cephalosporin should be used in combination with anti-anaerobic drugs (such as metronidazole) for the treatment of abdominal and pelvic infections; ceftazidime and cefoperazone can be used for various infections caused by Pseudomonas aeruginosa.

 

Fourth generation cephalosporin

Main varieties:

Cefepime, cefpirome.

Its characteristics are:

1. The antibacterial effect on Gram-positive bacteria is stronger than that of the third generation, but less than the first and second generations.

2. It is more effective than other cephalosporins for Enterobacter, Citrobacter, and Serratia.

3. The effect on Pseudomonas aeruginosa is similar to or slightly worse than ceftazidime.

Mainly used:

It is mainly used for various serious infections such as respiratory infections, urinary tract infections, biliary tract infections, sepsis, etc. The fourth-generation cephalosporin can be used for infections caused by bacteria such as Enterobacter aerogenes, Enterobacter cloacae, and Serratia, which are resistant to third-generation cephalosporins, and can also be used for neutrophil deficiency. Experienced treatment of fever patients.

In general:

1. The cephalosporins are stable to the β-lactamase generation one generation.

2. The toxicity to the kidney is lower than that of the first generation.

3. The first three generations of cephalosporins, the antibacterial power of Gram-positive bacteria is not as good as one generation, while the antibacterial force against Gram-negative bacteria is stronger than the first generation.

4. The fourth-generation cephalosporin has strong antibacterial activity against Gram-positive and negative bacteria.

5. Individual third and fourth generation can penetrate the cerebrospinal fluid.

All cephalosporins have poor antibacterial effects against methicillin-resistant Staphylococcus and Enterococcus, so it is not suitable for the treatment of infection caused by the above bacteria.

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