1, the first generation cephalosporin: mainly aimed at gram-positive bacteria, such as staphylococcus aureus, pneumococcus, streptococcus, etc.

2. The second generation cephalosporins: The antibacterial activity against Gram-positive bacteria is stronger than that of the first generation, and some Gram-negative bacteria such as Escherichia coli and Klebsiella pneumoniae also have certain antibacterial effects.

3. The third generation cephalosporins: The antibacterial activity against gram-negative bacteria was further enhanced, including Pseudomonas aeruginosa, Klebsiella pneumoniae and Klebsiella acidogenes. Some third-generation cephalosporins also have certain effects on gram-positive bacteria.

4. The fourth generation cephalosporins: The antibacterial activity against Gram-positive bacteria and Gram-negative bacteria is stronger than that of the previous three generations, especially those with strong drug resistance such as Klebsiella pneumoniae and Klebsiella acidogenes.

5. The fifth generation cephalosporin: It has a wide range of antibacterial activities against Gram-positive bacteria and Gram-negative bacteria, including some bacteria that produce β-lactamases.

6. Sixth generation cephalosporin: There is no clear sixth generation cephalosporin at present, but with the deepening of research, cephalosporins with more bacterial species and stronger antibacterial activity may appear in the future. Therefore, 1234567 generation cephalosporin antibiotics are mainly aimed at the strains shown in the above figure.