Cephalothin is a antibiotic belonging to the cephalosporin groupin particular, a first generation cephalosporins. In addition to belonging to this family, cephalothin is part of a larger group of antibiotics called β-lactams.
It is an antibiotic with penicillin-like properties. especially effective against gram+ bacteria thanks to a similar mechanism of action. Have you ever been prescribed it or do you know someone close to you who has taken it? We tell you more below.
Introduction: origin and structure
Cephalothin, like other antibiotics, is a substance produced by a living being. The first cephalosporin discovered comes from strains of a fungus, He Cephalosporium acremonium in 1948. This thanks to the fact that the scientist Giuseppe Brotzu had observed that the strains of this fungus produced a substance effective against salmonella
After further discoveries about these antibiotics, The first cephalosporin, cephalothin, is marketed..
Regarding the chemical structure of cephalosporins, they are derivatives of 7-cephalosporanic acid which, like penicillin, has a β-lactam ring.
In addition to this structure, they have a dihydrothiazine ring which, unlike penicillins, is made up of 6 atoms and not 5.
Mechanism of action
cephalothin has the ability to inhibit bacterial cell wall synthesis. It achieves this by inhibiting the final steps of peptidoglycan or murein synthesis.
It blocks the synthesis of this structure in both gram+ and gram- bacteria. This it manages to do this from within the cell wall, i.e. it must be placed inside and inhibit a process. This process is transpeptidation which occurs in the different steps of peptidoglycan synthesis.
The fact that they inhibit it from within implies that it has to enter and pass through the cell wall and that justifies that they are drugs more active in Gram + bacteria as the ease of passage is greater, access is facilitated.
What cephalothin exploits to enter gram bacteria are those channels or porins. As a consequence of the whole process, it kills bacteria, so it is a bactericidal drug. If it didn’t cause death and only inhibited the growth of the microorganism, it would be called bactericidal.
Peptidoglycan synthesis
The synthesis of this structure is a very complex process. that occurs in several steps and that the different points where the different antimicrobials will act are marked.
Cephalothin, being β-lactam, will act on a subsequent process, inhibits an enzyme system responsible for transpeptidation. This reaction occurs once all the amino acids of different elements have been added to finally form murein or peptidoglycan.
resistance mechanism
Antimicrobial resistance is a problem that is affecting the effectiveness of treatments both worldwide and in our country. This it is due to the misuse of antimicrobials by patients.
Bacteria have the ability to mutate to defend themselves against the attack of the drug and thus stay alive. If antibiotics are overused, the bacteria will mutate to become resistant. and that drug will stop working.
Consequently, new antibiotics with different mechanisms of action have to be developed to achieve the same effect. The problem is that these resources are limited and it is a very expensive process. As, antibiotics must be taken under medical prescription and without abusing them, as not taking more will be more effective against the infection.
This process, in the case of cephalothin, can result from three mechanisms of resistance:
- Through a enzyme capable of producing enzymatic hydrolysis of the β-lactam ring. These enzymes are called β-lactamase.
- Alteration of the sites of action of the antibioticwhich are penicillin-binding proteins.
- transport block through the cell wall, especially in gram bacteria.
adverse reactions
Cephalothin is a drug that must not be administered to pregnant womenunless the benefit outweighs the potential risks as there are no well-controlled studies available.
Adverse reactions have been described in several body systems. On the one hand, at the blood level, cephalothin can trigger agranulocytosis, granulocytopenia and haemolytic anemia. Thrombocytopenia and pancytopenia have also been observed in some patients. Gastrointestinal problems such as:
- Diarrhea
- Nausea
- vomit
- Abdominal pain
- pseudomembranous colitis
Moreover, can cause or worsen kidney failure, especially when combined with other nephrotoxic agents such as neomycin. Other adverse effects seen with cephalothin include injection site pain, drug fever, and, like other β-lactam antibiotics, allergic reactions ranging from skin rash to anaphylactic shock, although these are rare.
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