A novel method for isolation of Campylobacter spp. from environmental samples, involving sample processing, and blood- and antibiotic-free medium

Aims: To develop a method that involves sample processing, and blood- and antibiotic-free medium for isolation and enumeration of Campylobacter spp. from environmental samples. Methods and Results: The sample processing (preT) was standardized to minimize the population of competing bacteria. A blood- and antibiotic-free differential, Kapadnis-Baseri medium (KB medium) was formulated and tested for isolation of Campylobacter spp. in comparison with CAT medium. PreT-KB method was evaluated in comparison with the conventional viable count method and with the conventional most probable number (C. MPN) method for enumeration of Campylobcater from environmental samples. The results indicated that sample processing significantly reduced population of competing bacteria. The KB medium selected Gram-negative bacteria and differentiated Campylobacter from lactose-fermenting competing bacteria. The population of Campylobacter detected by preT-KB method was similar to that by conventional viable count method. While, the population of Campylobacter spp. determined by preT-KB method was higher than that by C. MPN method. In addition, the preT-KB method detected antibiotic sensitive campylobacters. Conclusion: The preT minimizes population of competing bacteria and the KB medium selects Gram-negative bacteria and differentiates Campylobacter from them. Therefore, Campylobacter can be isolated from environmental samples without using antibiotics. Significance and Impact of the Study: The preT-KB method is simple and facilitates isolation of antibiotic sensitive and enumeration of Campylobacter in the environmental samples. Therefore, the new method will be useful for isolation and enumeration of Campylobacter from water, food and sewage samples. Besides, it would also detect antibiotic-sensitive campylobacters, which are not detected by conventional viable count and MPN methods.