Isolation of Campylobacters from the canals of Bangkok metropolitan area

The 100 ml of canal water samples of 36 canals in Bangkok Metropolitan Area were examined in three periods starting from July-September 1988, November 1988-January 1989 and February-April 1989. Each time the 52 water samples were checked. Of 156 water samples, 116 strains of Campylobacter species were isolated. They were 63.79 per cent (74 strains) of C. cryaerophila and 36.21 per cent (42 strains) of C. cryaerophila-like organisms. The differentiation was determined by urease activity test. C. cryaerophila was isolated from 44.23 per cent (23 strains), 51.19 per cent (27 strains) and 46.15 per cent (24 strains) and also C. cryaerophila-like organism from 28.85 per cent (15 strains), 19.23 per cent (10 strains) and 32.69 per cent (17 strains) of the 52 samples during each period respectively. Since C. cryaerophila and C. cryaerophila-like are aerotolerant Campylobacter, they grow well in aerobic conditions at 25 degrees-36 degrees C. On the contrary, thermophilic Campylobacter such as C. jejuni, C. coli and C. laridis require atmosphere containing 5 per cent O2, 10 per cent CO2, 85 per cent N2 and temperature at 36 degrees-42 degrees C, so the environment in the canals is unfavorable for their growth. The etiological role of C. cryaerophila in pathogenesis in humans is still unknown, and requires furthers study. This study shows that canals can be an important source of these two Campylobacter species that might be potential pathogens in the future.