Phenelfamycins, a novel complex of elfamycin-type antibiotics. III. Activity in vitro and in a hamster colitis model.

Phenelfamycins A, B, C, E, F and unphenelfamycin make up a recently isolated group of elfamycin-type antibiotics. All of the phenelfamycins were active against Gram-positive anaerobes, including Clostridium difficile. Phenelfamycin A was also active in vitro against Neisseria gonorrhoeae and Streptococci. Phenelfamycin A was found to be effective in prolonging the survival of hamsters in an animal model of C. difficile enterocolitis. After oral administration of phenelfamycin A to hamsters, antibiotic was detected in the caecal contents but not in the blood.