RESUMEN
AIMS: To examine the influence of pH of triple sugar iron (TSI) agar medium on the detection of hydrogen sulfide (H(2)S) production in Campylobacter hyointestinalis ssp. hyointestinalis (CHH). METHODS AND RESULTS: TSI medium was adjusted by the addition in HCl or NaOH to cover a pH 6.0-9.0. One loopful of bacterial growth of CHH strain ATCC 35217 was inoculated into each different pH medium, and incubated at 37 degrees C under micro-aerobic conditions. The H(2)S production was not detectable even after incubation for 72 h in acidic medium pH; however, TSI with alkaline pH (8.0-9.0) allowed detection as early as 3 h of incubation. A total of 20 CHH strains from various animal sources were examined for the detection of H(2)S production in TSI medium with pH 9.0. The H(2)S was detected in all the strains examined within 12 h, and the judgment was unambiguous. CONCLUSION: The results showed that the detection of H(2)S production by CHH was influenced by medium pH, and TSI with alkaline condition is highly sensitive. SIGNIFICANCE AND IMPACT OF THE STUDY: The findings of the present study suggest that TSI medium with alkaline pH contributes to fast detection and led to unambiguous judgment of H(2)S production by CHH.