Stability of pathogenic bacteria from laboratory animals in various transport media

Abstract

The stability of pathogenic bacteria from laboratory animals was investigated in various transport media at different temperatures. Bordetella bronchiseptica and Salmonella typhimurium survived for 8 days in phosphate-buffered saline (PBS, pH 7·0) at 37, 24, 4 and -20°C; Brucella canis at 24, 4 and -20°C; Corynebacterium kutscheri at 4 and -20°C; and Pseudomonas aeruginosa at all but -20°C. A marked decrease in numbers of Pasteurella multocida and Past. pneumotropica was observed in PBS at all temperatures. Skimmed milk in PBS improved the survival of Pasteurella spp. and Ps. aeruginosa at -20°C. Neither glycerin, ascorbic acid nor sodium thioglycollate improved survival. The numbers of viable B. canis, Ps. aeruginosa and S. typhimurium were maintained in blood or faecal specimens held for 8 days at 4°C. These results indicated that transport in PBS at 4°C was the only method satisfactory for all species of pathogenic organisms tested, but Pasteurella spp. were the most difficult to maintain.