Talk:Cephalosporin

Hi

Hi , i am 6th year medical student and i have problem identifying the proper antibiotic for specific infection according to the causative organism (which is best for gram positive , nigative ...) ... any help ???

Pick up a copy of the Sanford Guide to Antimicrobial Therapy? It's a standard resource for such things. http://www.sanfordguide.com/

Anybody got any idea how this antibiotic (Cephalosporin) is related to immunosuppressant?

No, but there is a immunosuppressant called cyclosporin. Daevatgl 09:56, 25 September 2005 (UTC)

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Help needed

The classes of Cephalosporins are complicated.

• Structure Activity Relationships "Antibacterial Agents; Structure Activity Relationships," André Bryskier MD; beginning at pp83

This article does a superb job of elucidating the structural activity relationships. It utilizes a different grouping than the traditional generations, that should also be reflected in the article, though the generations should be retained. Farseer 07:46, 24 December 2005 (UTC)farseer

The first generation Cephalosporins are clearly derivitives of the natural antibiotic, based on the core shown. Second generation members seem to have come about from modification of the first to increase the activity against gram negative bacteria and anaerobes.

Cephamycins (cephems)

In searching for these, the cephamycins turned up, which replace a hydrogen on the four membered ring with a methoxy group. All or nearly all are anti-anaerobes.

Third generation

As newer compounds were prepared, the spectrum was improved significantly and a new generation was recognized - the third. Most of the these have a five membered ring.

File:3rdcore.png 150px 3rd generation core structure 8-[2-(2-amino-1,3-thiazol-4-yl)acetyl]amino- in the eight position off the main cephalosporin stucture (the group to the right of the four member cephalosporin core ring).

But not all do. This aminothiazolyl moeity is a hallmark of third generation cephs. And either it or the aminothiadiazolyl variant seem to be hallmarks of the fourth generation.

Fourth generation

Fourth generation members also often have this same moeity, and generally add a positively charged aromatic with a charged nitrogen seeming to be the hallmark.

For example: cefipime and cefpirome have the two major charged moeities that seem to be the hallmark of fourth generation cephalosporins:

cefepime

cefpirome

Not all sources agree on which generation each member belongs to. Some members assigned as first generation have the charged moeity that is a hallmark of fourth generation, while lacking the five member ring. Some fourth generation cephalosporins also lack the five member ring.

Cefalonium and cephaloridine (classed as 1st generation), ceftazidime (classed as 3rd generation) and the as yet unclassified cefempidone have a similar structure that appears to be more appropriately classified as fourth generation. Cefalonium and cephaloridine lack the aminothiadiazolyl or aminothiazolyl moeity that are hallmarks of most third and fourth generation cephalosporins and that provide their antipseudomonal character.

Can anyone point to a definitive source for classifying the cephalosporins by generation? In other words, who defined what constitutes each generation.

"New generation"

Ceftobiprole and ceftobiprole medocaril are strong anti-MRSA antipseudomonal antibiotics currently in phase III trials. They are asserted to be a "new generation" of anti-MRSA cephalosporins. Ceftobiparole contains the aminothiadiazolyl moiety and lacks the charged moeity typical of 4th generation. So, should it be classed as 3rd generation, or 4th?

ceftobiprole

ceftobiprole medocaril

Oxacephems

To add the confusion, the new oxacephems (rarely called oxycephems) substitute an oxygen for the sulfur in the main six member ring. They so far also include the methoxy group that demarks a cephamycin. However, it seems likely that will change and an oxacephalosporin will be produced.

flomoxef

Sulfoxy/sulfoxa/sulfoxyl cephalosporins

Two new members substitute a sulfoxy group for the sulfur in the six memebr main ring. They seem to provisionally be fourth generation members. But lacking a spcecific definition, that remains unclear.

cefmepidium chloride

Other categorization schemes

There is also a second major categorization scheme that refers to the cephalosporins and cephems by group (Groups 1 to 7). The groupings overlay the generations and also separate the parenteral members from the oral members. I have found a good reference for this, however, for many members, classification is still not obvious.

Other issues

It may be that classification into generations depends on the spectrum that each member displays. Given the large variation in member properties, there is an equally large diversity in the antibiotic spectrum.

Then lastly, the antipseudomonal designation seems to change rapidly as resistance develops in use. Individual members that were considered antipseudomonal a few years ago, are no longer of much use in that regard and in many sources are no longer considered to by antipseudomonal.

So how should these be designated and grouped?

Farseer 21:20, 19 December 2005 (UTC)farseer

Cross-reactivity

In light of the article in the Journal of Family Practice I put a note advising that the cross-reactivity may not be as high as the widely quoted 10% - the article, looking at ~3400 penicillin allergic patients compares the reaction rate with those of non-penicillin allergic patients (N=35,450) and shows similar rates for many of the 2nd generation and all 3rd generation cephalosporins reported on. My background however is neuroscience, not pharmacology, so others may wish to examine the article, which goes on to suggest use of a table of side-chain similarities to predict cross-reactivity.

References

Comments on text

Peptidoglycan is important for the structural integrity of both Gram-positive and Gram-negative bacteria. The difference in susceptibility of Gram-positive and Gram-negative bacteria to beta-lactam antibiotics is due to the inability of certain beta-lactams to cross the outer membrane of Gram-negative bacteria and to differences in the peptidoglycan synthesis machinery . Siegele (talk) 20:27, 9 December 2007 (UTC)

please add graph showing generation activity with what organsims

would be useful - it is in most pharm textbooks. —Preceding unsigned comment added by 207.151.253.234 (talk) 01:20, 5 November 2008 (UTC)

bar chart would be useful to see how much gram + and - coverage there is. —Preceding unsigned comment added by 163.40.12.37 (talk) 14:17, 11 March 2009 (UTC)

IMHO, not useful to show such info, and also WP:NOT#NOTTEXTBOOK - is gram status of usefulness with respect to antibiotic sensitivities (OK helps distinguish one bacteria from another, but not per se which antibiotic to empirically use in a given clinical situation, and anyway, by time have microbiological result also have precise antibiotic sensitivities). See my comment at WT:MED (settling myself up to be ridiculed, or at least educated to the contrary) David Ruben ^Talk 01:18, 12 March 2009 (UTC)

Rocephin for Lyme Disease

To my knowledge Rocephin is the drug used for IV dosing for Lyme Disease that does not respond to earlier oral dosing. —Preceding unsigned comment added by 151.191.175.205 (talk) 16:19, 16 September 2009 (UTC)

Yes indeed, although it's an off-label use if memory serves. Cefotaxime or benzylpenicillin can be used as well. Fvasconcellos (t·c) 17:05, 16 September 2009 (UTC)

compound isolation year incorrect

The article currently states that Giuseppe Brotzu took cultures of cephalosporium acremonium in 1948 - this is the year that his paper announcing the discovery was published, inside which he gives the date of taking the culture as 1945 http://pacs.unica.it/brotzu/brotzuen.pdf — Preceding unsigned comment added by 92.235.204.100 (talk) 17:08, 9 June 2011 (UTC)

A neglectably little issue about Cefatrizine.

To the best of my knowledge does Cefatrizine belong to the second and not the first generation. Its spectrum includes accordingly many Gram negative bacteria. --MedMan (talk) 17:36, 25 March 2014 (UTC)

Ceftamere

I removed mention of "Ceftamere" from the list because I can find no mention of it apart from websites that appear to get their info from this page. Whether it's a typo or some other type of error, it needs to be confirmed in a reliable source that predates Wikipedia (or is clearly not dependent on the Wikipedia article) before being included in the list. -- Ed (Edgar181) 17:52, 13 August 2019 (UTC)

New table proposal

I have drafted a new overview table from the existing one. My work is here: User:Lukelahood/sandbox#Overview_table. I plan on putting it on this article page soon. I believe it is better organized, with the most used medications towards the top, and the experimental ones towards the bottom.

Any objections?

Lukelahood (talk) 20:51, 28 December 2021 (UTC)

Cephalosporin Core Structure

The image used for the core structure of cephalosporins is incorrect. The R1 and R2 groups should be switched. I'm not sure how to update the image. Any help would be greatly appreciated! Koneha (talk) 19:19, 18 March 2023 (UTC)

Faulty Link

Hello! I'm not sure what to say here or how to edit, but I thought I would put here that the link for source 19 is faulty. It doesn't load up any relevant info and is an empty search page.

Thanks! 204.111.224.88 (talk) 01:49, 1 September 2023 (UTC)