Modification of Cary-Blair Transport Medium for Pasteurella multocida and Mannheimia haemolytica

Abstract

The aim of this study was to evaluate the effectiveness of Cary-Blair, Amies and modified Cary-Blair medium for transport of P. multocida and M. haemolytica strains. Pure cultures of nine strains of P. multocida, representing all subspecies, and nine strains of M. haemolytica were inoculated into the media to test their convenience. The ability of the strains to survive in each of these media was determined periodically (on days 5, 10, 15, 20, 30, 45, 60, 75, 90, respectively) at different temperatures (alternatively at 21°C and 4°C) and at room temperature (constantly at 21°C). Comparing with the Cary-Blair and Amies medium, P. multocida strains survived for 45 days and M. haemolytica strains for 30 days in modified Cary-Blair medium. Based on the present observation, Cary-Blair medium modified by the addition of horse blood serum is the most effective of those tested media for the transport of P. multocida and M. haemolytica strains.