Aims: The role of antibiotics produced by bacterial symbionts of entomopathogenic nematodes is to suppress growth of microbes in the soil environment. These antibiotics are active against Gram-positive and Gram-negative bacteria, and were tested against mastitis isolates from dairy cows.
Methods And Results: Two bioassays were adapted for Xenorhabdus antibiotics; an overlay method on agar plates, and serially diluted, cell-free, Xenorhabdus cultures.