title: The use of aqueous cetylpyridinium chloride as a transport medium for suspected tuberculous tissues from badgers.
abstract: Deterioration of tuberculous tissue specimens from badgers during transit in the post was simulated in the laboratory, and it was found that unpreserved tissues showing miliary lesions and initially producing a confluent growth of Mycobacterium bovis became culture-negative over a period of 4 days at ambient summer temperatures (>20 degrees C). These findings implied that false negative results may be obtained from specimens containing only small numbers of bacilli following delays of 2 days between collection and culture. A bench trial of cetyl pyridinium chloride and bromide as preservatives showed viable bacillary numbers were maintained well. A field trial of a 1% aqueous solution of the chloride salt as a transport medium was carried out on 666 split tissue submissions and a significantly improved isolation rate was found from the preserved samples, with 40 (93%) of the total of 43 isolates of M. bovis compared with 27 isolates (63%) when no preservative was used. Isolation using the guinea pig test was attempted on 354 of these samples and yielded 38 (93%) of the 41 isolates, compared with culture of preserved samples which yielded 39 isolates (95%), an insignificant difference. The use of this transport medium maximised cultural isolations, such that no significant gain was achieved by the continued use of the animal test.
authors: Tuberculosis Unit, MAFF Veterinary Investigation Centre, Cheltenham Road, Gloucester, England.
authors: J
authors: J
authors: Gallagher
authors: G W
authors: GW
authors: Davis
authors: D M
authors: DM
authors: Horwill