A novel method for isolation of Campylobacter spp. from environmental samples, involving sample processing, and blood- and antibiotic-free medium M. Baserisalehi, N. Bahador and B.P. Kapadnis Department of Microbiology, University of Pune, Pune, India 2003/1144: received 13 Decmeber 2003, revised 21 May 2004 and accepted 21 May 2004 ABSTRACT M. BASERISALEHI, N. BAHADOR AND B.P. KAPADNIS. 2004. 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. Keywords: Campylobacter, faeces, KB medium, sample processing, water. INTRODUCTION Campylobacter is now recognized as the most common cause of acute bacterial diarrhoea worldwide and is estimated to cause approximately 4 million cases each year in the USA alone (Altekruse et al. 1998). The natural habitat for most Campylobacter spp. is the intestine of birds and warm-blooded animals, including sea gulls and several other wild birds (Kapperud and Rosef 1983). Campylobacter may enter the environment including, drinking water through the faeces of animals, birds or infected humans (Blaser et al. 1980, 1984). The presence of Campylobacter, in the environmental samples can be taken as a sign of recent contamination, because they are unable to multiply outside warm-blooded animals, and their short survival Correspondence to: B.P. Kapadnis, Department of Microbiology, University of Pune, Pune 411007, India (e-mail: bpkap@unipune.ernet.in). ª 2004 The Society for Applied Microbiology Journal of Applied Microbiology 2004, 97, 853–860 doi:10.1111/j.1365-2672.2004.02375.x