An evaluation of five preservation techniques and conventional freezing temperatures of -20°C and -85°C for long-term preservation of Campylobacter jejuni

Aims: This study aimed to identify a simple, inexpensive preservation technique that will allow a quick and reliable recovery of Campylobacter jejuni following long-term periods of preservation. Methods and Results: Preservation techniques include (i) Cryobank microbial preservation system using hypertonic 'cryopreservative solution' and glass beads, (ii) Cryobank microbial preservation system using defibrinated lysed horse blood and glass beads, (iii) FBP medium, (iv) 15% glycerol/85% nutrient broth no. 2 culture, and (v) 50% glycerol/50% nutrient broth no. 2 culture. Each preservation technique was evaluated over a 1-year period at conventional freezing temperatures of -20°C and -85°C. Replacement of 'cryopreservative fluid' in commercially prepared vials of glass beads with lysed horse blood increased the duration of preservation of Camp. jejuni by up to 6 months. Conclusions: FBP medium proved the most successful preservation technique with 100 and 80% recovery after 1 year at -85°C and -20°C, respectively. Significance and Impact of the Study: This study demonstrated a simple inexpensive preservation method for long-term storage of Camp. jejuni.