Comparison of a blood-free medium and a filtration technique for the isolation of Campylobacter spp. from diarrhoeal stools of hospitalised patients in central Australia.

Single specimens of diarrhoeal stool from 676 patients, mostly aboriginals aged less than 5 years, admitted to Alice Springs Hospital, central Australia, for diarrhoea between Sept. 1988 and Feb. 1989, were examined for Campylobacter spp. by culture on a blood-free medium with selective supplement (BFM; Oxoid) and blood agar overlaid with a membrane filter (FM). Campylobacter spp. were isolated on either BFM or FM or both from 225 patients. Campylobacter spp. were isolated on BFM alone from 75 patients and on FM alone from 213 patients (p less than 0.001; chi 2 test). Most campylobacters isolated on BFM were C. jejuni. All C. jejuni subsp. doylei, all "C. upsaliensis" except one, all C. laridis, C. fetus subsp. fetus and several uncharacterised Campylobacter isolates were isolated on FM only. C. jejuni was isolated on BFM but not FM from several patients, and vice versa. Serotyping of C. jejuni and C. coli isolated from both media showed the serotypes recovered from the two media to be different in some patients. In some patients concurrent infection with several species or serotypes (up to five) of Campylobacter, or both, was shown for the first time by the use of FM. We conclude that the use in combination of a selective medium and a non-selective medium with a filtration technique are better than either medium alone for the isolation of Campylobacter spp.