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.

Campylobacter jejuni and/or Campylobacter coli was cultured from 218 of 1,078 patients of all age groups admitted to Alice Springs Hospital, Alice Springs, central Australia, between July 1988 and June 1989 for treatment of diarrhea. One hundred sixty-six Campylobacter colonies from 127 patients were subjected to O serotyping by using the Penner typing scheme. All except 29 colonies could be serotyped. A total of 46 serotypes were identified, and the predominant serotypes were O:8, 17, O:22, O:1,44, and O:19. A large proportion of colonies reacted with more than one antiserum, and nine serotypes had antigenic compositions not observed previously. Several patients had multiple infections with more than one serotype, and some patients were shown for the first time to be infected with up to three different serotypes. Repeated reinfections with different serotypes were seen in some patients. In some patients, provided it was not due to reinfection with the same serotype, long-term excretion of the same serotype was seen, and for the first time, one patient showed evidence of excretion of the same serotype for up to 73 days.