Cephalosporin belongs to a class of broad-spectrum antibiotics derived from a fungus (genus Cephalosporium). They are similar to penicillins and are used on penicillin-resistant infections.
Cephalosporins are semisynthetic antibiotics produced by fungi Cephalosporium. We may say that cephalosporin antibiotics are "very close relatives" of penicillins, because cephalosporins mechanism of action, mechanism of resistance, and some other properties are identical to penicillins. Both cephalosporins and penicillins belong to β-lactams (beta-lactam antibiotics.)The main value of cephalosporins is their broad spectrum of antimicrobial activity. Cephalosporins are widely and successfully used in medicine in the treatment of different bacterial infections. Cephalosporins affect bacteria's cell wall. This leads to the death of a harmful bacteria. Cephalosporins distribute in human body in satisfactory concentrations except central nervous system. Only few of them achieve adequate concentration in cerebrospinal fluid (Cefuroxime, Cefotaxime, Ceftriaxone, Ceftazidime) and can be used to cure meningitis or brain abscesses.
Cephalosporins are beta-lactam compounds in which the beta-lactam ring is fused to a 6-membered dihydrothiazine ring, thus forming the cephem nucleus. Side chain modifications to the cephem nucleus confers 1) an improved spectrum of antibacterial activity, 2) pharmacokinetic advantages, and 3) additional side effects. Based on their spectrum of activity, cephalosporins can be broadly categorized into four generations.
The cephalosporins are a group of semisynthetic derivatives of cephalosporin C, an antimicrobial agent of fungal origin. They are structurally and pharmacologically related to the penicillins. Because the cephalosporins are structurally similar to the penicillins, some patients allergic to penicillin may also be allergic to cephalo- sporin drugs. The incidence of cross-sensitivity is estimated to be 5 to 16 percent.
This group of antimicrobials, though similar to the penicillins in action, have different chemical structures. They tend to be more stable than penicillins to many of the bacterial beta-lactamases, and have a broader spectrum of activity than do the penicillins.
There are many cephalosporins that are different classes, and which vary in their spectrum of activity, but all of the so called “true” cephalosporins derive from cephalosporin C produced by Cephalosporium acremonium.
These drugs are usually bactericidal. They inhibit mucopeptide synthesis in bacterial cell walls.
Their advantage over the penicillins are that they resist hydrolysis by the enzyme penicillinase which is secreted by a number of bacteria. The cephalosporins can be effective, but those that are taken orally are not in most cases the drug of choice in systemic infections.
Their broad spectrum of activity and safety profile make the cephalosporins one of the most widely prescribed class of antimicrobials. The earlier generation cephalosporins are commonly used for community-acquired infections, while the later generation agents, with their better spectrum of activity against gram-negative bacteria make them useful for hospital-acquired infections or complicated community-acquired infections.