Caenorhabditis elegans has previously been used as an alternative to mammalian models of infection with bacterial pathogens. We have developed a liquid-based assay to measure the effect of bacteria on the feeding ability of C elegans. Using this assay we have shown that Pseudomonas aeruginosa strain PA14, Burkholderia pseudomallei and Yersinia pestis were able to inhibit feeding of C elegans strain N2. An increase in sensitivity of the assay was achieved by using C elegans mutant phm-2, in place of the wild-type strain. Using this assay, P. aeruginosa PA01 inhibited the feeding of C elegans mutant phm-2. Such liquid-based feeding assays are ideally suited to the high-throughput screening of mutants of bacterial pathogens. (C) 2002 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.