Brian Foley wrote:
> ampicillin and penicillin inhibit the formation
> of the gram possitive cell wall. They have
> no effect on gram negatives.
Not true. Ampicillin is used quite effectively against many gram
negatives. Especially in urinary tract infection the concentration of
ampicillin is usually sufficiently high (many times the MIC) to kill
simple _E. coli, _Klebsiella_ species, and _Proteus mirabilis_ (despite
the _in vitro_ result). It will also take out many _Haemophilus
influenzae_, mind you it's important that your local antibiogram shows a
reasonable susceptibility profile.
There are many other examples of where even penicillin is useful against
gram negatives, e.g., some anaerobic gram negative bacilli.
Gary
--
********************************************************
Dr Gary Lum
Director of Microbiology
Royal Darwin Hospital
Microbiologists do it with culture and sensitivity
Meet me at http://www.ozemail.com.au/~glum/index.html
E-mail me at glum at ozemail.com.au or gary.lum at nt.gov.au
