Tuesday, January 17, 2012

Cephalosporin antibiotics

Cephalosporin antibiotics

Cephalosporins, commonly used antibiotics, are made from a fungus. Cephalosporins work against both Gram-negative and Gram-positive bacteria. When compared to penicillin, cephalosporins are more effective against Gram-negative bacteria and less effective against Gram-positive bacteria. However, both penicillin and cephalosporins have similar chemical compositions. Cephalosporins are broadly divided into the following four classes:

First-generation cephalosporins

Cefazolin sodium, the first generation cephalosporin, is active against staphylococci, streptococci, H. influenzae, P. mirabilis, C. diptheriae and Listeria.

Second-generation cephalosporins

These drugs are more effective for anaerobic and some Gram-negative organisms than the first generation cephalosporins. The antibiotics may therefore be used for infections that cannot be treated with other antibiotics, such as infections due to E. coli, Klebsiella species and Haemophilus influenzae. Cefprozil, cefurxime axetil, cefaclor and cefdinir, the 2nd generation cephalosporins, are used for treating symptoms-sinus.

Studies concluded that 250 mg of cefuroxime axetil is better than cefaclor in case of patients suffering from acute maxillary symptoms-sinus. Efficacy of amoxicillin and cefuroxime are same.

Cefoxitin sodium, the second-generation cephalosporin, works against B. fragilis, which is resistant to many common antimicrobial drugs.

Cefuroxime sodium, the second-generation cephalosporin, is similar to other cephalosporins of the second generation. It is administered to children suffering from bacterial meningitis.

Third-generation cephalosporins

The third-generation cephalosporin antibiotics are active against a wider range of Gram-negative bacteria. The drugs work against scores of strains resistant to 1st and 2nd generation cephalosporins and other antibiotics. Therefore, the drugs may be useful to treat infections caused by Providencia, Serratia and Citrobacter species. These drugs can also reach inflamed meninges, thus used for meningeal infections caused by Streptococcus penumoniae and H. influnenzae. As cephalosporins move from first to thrid generation, their activity against Gram-negative bacteria increases and activity against Gram-positive bacteria decreases. Since 2nd and 3rd generation drugs are highly resistant to cephalosporinases, the beta-lactamase enzymes released by inactive cephalosporins or some organisms, these are more effective for Gram-negative bacteria. The third generation cephalosporins are used for intracranial abscess caused by streptococci, and dural sinus thrombophlebitis, a complication of symptoms-sinus.

Cefotaxime sodium (claforan), the third generation cephalosporin, is known for ant-bacterial activity against numerous strains that are resistant to many other antibiotics, and Gram-negative and Gram-positive bacteria. The drug is prescribed to patients suffering from serious infections caused by microorganisms.

Ceftazidime (fortaz), the third generation cephalosporin, is active against bacterial strains resistant to amino glycosides and P. aeruginosa and other Gram-negative bacteria. It also works against Gram-positive organisms.

Ceftriazone sodium (rocephin), the third generation cephalosporin, is effective for most of the Gram-negative and Gram-positive bacteria.

Fourth-generation cephalosporins

The fourth generation drugs cover a wide range of anti-microbial activities. The drugs are more stable against beta-lactamase enzyme action when compared to the 3rd generation cephalosporins.

Cefepime, the first cephalosporin of the 4th generation cephalosporins, works against Gram-negative (P. aeruginosa) and Gram-positive (staphylococci and streptococci) bacteria. The drug is more effective against Enterobacteriaceae than the 3rd-generation cephalosporins.

Cefepime hydrochloride (maxipime), the fourth generation cephalosporin, is prescribed for infections caused by K. penumoniae or E. coli, and soft and skin tissue infection due to staphylococci and streptococci.

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