Surprise discovery as clam found to be producing complex antibiotic

A clam has been found to be synthesising erythromycin, making it the first known animal to make such a complex antibiotic.

Erythromycin had been thought to be made only by actinobacteria. Now, it seems that the Asiatic hard clam Meretrix petechialis can make it to defend itself from infection in its muddy marine habitat.

The researchers began by searching for genes in the clam that changed their expression before and after an infection. They identified a gene encoding an enzyme (erythronolide synthase, ES) involved in the formation of an intermediate compound in the biosynthesis of erythromycin.