Agglomerins are bacterial natural products, identified as metabolites of Pantoea agglomerans which was isolated in 1989 from river water in Kobe, Japan. They belong to the class of tetronate antibiotics, which include tetronomycin, tetronasin, and abyssomicin C. The members of the agglomerins differ only in the composition of the acyl chain attached to the tetronate ring. They possess antibiotic activity against anaerobic bacteria and weak activity against aerobic bacteria in vitro. The structures were solved in 1990. Agglomerin A is the major component (38%), followed by agglomerin B (30%), agglomerin C (24%), and agglomerin D (8%).