Fumarate hydration test for differentiation of Campylobacter and Helicobacter species

A total of 65 Campylobacter and Helicobacter strains comprising 15 species were tested for fumarate hydration by using a rapid high-performance liquid chromatographic (HPLC) method. All strains of C. jejuni, C. coli, C. jejuni subsp. doylei, C. fetus, C. hyointestinalis, C. lari, "C. lari variant", C. upsaliensis, H. fennelliae and H. pylori hydrated fumarate, whereas no strains of C. sputorum (all three biovars), H. cinaedi or H. mustelae did. L-malic acid was detected in the supernatant of the cultures of all strains that hydrated fumarate, but not in the culture supernatant of any of the strains that failed to hydrate fumarate. These findings show that all Campylobacter and Helicobacter strains that hydrated fumarate were able to form L-malic acid from fumarate. HPLC determination of organic acid is a rapid method that requires no chemical treatment before analysis. Because it is reproducible, the HPLC fumarate hydration test should be useful as conventional method for identification of Campylobacter and Helicobacter spp.