Metabolism of chloramphenicol by the producing organism

Abstract

When 14C-labeled chloramphenicol was added to chloramphenicol-producing cultures of Streptomyces strain 13s, radioactive p-nitrophenylserinol, N-acetyl-p-nitrophenylserinol, p-nitrobenzyl alcohol, and p-nitrobenzoic acid were formed. The rate of catabolism varied with culture conditions. It was fastest during rapid growth on a medium supporting low chloramphenicol production. Periodic analysis of cultures indicated that p-nitrophenylserinol accumulated only transitorily and was rapidly N-acetylated. In support of this conclusion 14C-labeled p-nitrophenylserinol was rapidly and completely metabolized, giving mainly the N-acetyl derivative. p-Nitrobenzyl alcohol and p-nitrobenzoic acid were formed in only small amounts during catabolism of chloramphenicol or p-nitrophenylserinol. Chloramphenicol inhibited growth of Streptomyces strain 13s by increasing the lag phase. It also appeared to inhibit antibiotic synthesis. However, cultures supplemented with D-glucose-U-I4C produced radioactive chloramphenicol even when exposed to high concentrations of the antibiotic, and the titer at any time thus represents the product of both catabolic and biosynthetic reactions.