Choice among penicillins and cephalosporins.

Abstract

In 1944 medical personnel in London was scattered and com munications were difficult, but a meeting at the Royal Society of Medicine in November of that year was one of the most crowded ever held there. Such an audience could then have been attracted by only one subject, penicillin, which at that time was proving its worth in the treatment of battle casualties. Of the opening speakers, Fleming is fully reported in the Proceedings, but Florey1 much more briefly, and without reference to a prediction he made-namely, that day chemists will manipulate the penicillin molecule to improve its performance. Fulfilment of this prophecy came 15 years later with the isolation of the penicillin nucleus, 6-aminopeni cillanic acid. Until then about 30 natural penicillins had been known, whose formation could be induced by adding the ap propriate precursor to the culture medium. But the only functioning precursors were derivatives of acetic acid. Removal of the side chain enabled others of quite different nature to be attached and by such means several thousand new penicillins were eventually produced. Later the process of synthetic modification was applied to 7-aminocephalosporanic acid, the nucleus of cephalosporin C. The result of these efforts is that many penicillins and cephalo sporins are now available for clinical use. It is difficult for the clinician to distinguish between the particular merits of so many similar antibiotics or to recognize the purposes for which some of them may fail, and it is the object of the following analysis to make these tasks easier. The list of those considered cannot be exhaustive, and is confined mainly to those now available in this country. It will be necessary to go over some old ground, and indeed to summarize developments which have occupied a further 15 years since Florey's original prophecy.