Carbenicillin summary

David Nunn David_Nunn at
Fri Jul 30 15:28:40 EST 1993

In article <gibbs.744057424 at>, gibbs at
(James Gibbs) wrote:
> Just yesterday I posted a question as to the use of carbenicillin as a
> replacement for ampicillin in bacterial plates. I've already received
> about a dozen e-mail replies, so I decided to post a summary. If you're
> just dying to tell me your variation, I'd be happy to read your e-mail. :)
> Suppliers: Sigma and USB. The sigma product dissolves clear and the USB
> product is less soluble, but allegedly more stable. Much more expensive
> than ampicillin ($49.70/G Sigma).
> Stock: 300mg/ml in water or 50% ethanol, frozen in 1ml aliquots at -20C.
> Concentration in plates: 100ug/ml in most cases, but one person said 50
> and another said 200 for higher copy plasmids, less for low copy plasmids. 
> Stability: Most people run out by 2-3 weeks, but one said he used
> two-month-old plates with no problem. Another said several months. No one
> could confirm any increased temperature stability over amp.
> Misc: Several prople told me that carbenicillin results in fewer satellite
> colonies than ampicillin, but no one knew why.
> -- 
> Jim
> gibbs at

I think you will find that Sigma no longer sells carbenicillin and USB now
sells an indacryl salt rather than the normal sodium salt.  At any rate it
is extremely expensive compared to ampicillin and, unless you are filthy
rich there is no reason to use it for E. coli.  We are forced  to use it in
Pseudomonas aeruginosa because of the relative resistance of this bug to
ampicillin.  I would gladly give up the use of carbenicillin if I could. 
We still use ampicillin for E. coli, with the caveat that you just can't
expect to keep your plates for longer than a month and still retain good
selection. Still it is much cheaper than ampicillin ($20/g for carb vs.
$1/g for ampicillin). If you still insist on carbenicillin the cheapest
supplier is Gemini Bioproducts,
5115-M Douglas Fir Road
Calabas, CA 91302
5g for $100

The reason not many people sell carbenicillin anymore is that is is no
longer used therapeutically (too much sodium) hence not produced by the big
drug companies.
David Nunn
Department of Microbiology
University of Illinois
Urbana, IL 61801
(217) 333-6131

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