THE ISOLATION OF SUCROSE-FERMENTING SALMONELLA-MBANDAKA

During media trials to evaluate the use of Brilliant Green Agar for th e primary recognition of Salmonella, strains presenting fermentation r eactions were observed. All fermenting strains (84 out of 145) belonge d to the serotype Salmonella mbandaka (58%), and the activity was expr essed on three batches of Brilliant Green Agar and one of Xylose-Lysin e Desoxycholate Agar. It was established using individual lactose and sucrose broth that the reaction in these media was due to sucrose ferm entation. The most frequently isolated Salmonella in this laboratory d uring 1990 was S. mbandaka (61%) i.e. 65 of the 106 isolates during th is period. Primary differentiation of Salmonella from other members of the family Enterobacteriaceae on media incorporating sucrose would ha ve resulted in 36% of Salmonella isolates not being recognised. BGA an d XLD agar therefore would not be suitable for primary isolation of Sa lmonella from clinical material with such a high percentage of the maj or isolate, S. mbandaka, having the ability to ferment surcrose.