Use of Salicin-Rhamnose-Cellobiose-4-Methylumbelliferyl-b-D Glucuronide–Sorbitol MacConkey (SRC-MUG-SMAC) Differential Agar for the Presumptive Identification of Escherichia coli O157 from the Primary Isolation Step

Authors : Murat GÜLMEZ, Leyla VATANSEVER, Abamüslüm GÜVEN, Berna DUMAN, Çiğdem SEZER

Pages : 1137-1141

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Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :A differential agar for the further detection of presumptive Escherichia coli O157 strains among typical sorbitol negative and cefixime-tellurite resistant strains was investigated. For this purpose, in parallel to colonies of 8 reference strains, 1130 suspect colonies picked from the surface of cefixime-tellurite insert ignore into journalissuearticles values(CT);-sorbitol MacConkey insert ignore into journalissuearticles values(SMAC); insert ignore into journalissuearticles values(CT-SMAC); agar plates of food samples insert ignore into journalissuearticles values(white cheese, raw milk and ground beef); were transferred to differential agar plates. After a 6-h incubation period at 42 ºC, only 47 insert ignore into journalissuearticles values(4.15%); of the 1130 colonies appeared as typical E. coli O157 on the differential agar plates insert ignore into journalissuearticles values(100 x 15 mm); gridded into 25 numbered sections. Salicin insert ignore into journalissuearticles values(S);, rhamnose insert ignore into journalissuearticles values(R); and cellobiose insert ignore into journalissuearticles values(C); were tested separately and together in combination with MUG. The best results were obtained from the combined use of the 3 in SMAC medium insert ignore into journalissuearticles values(SRC-MUG-SMAC);. When violet red bile lactose agar insert ignore into journalissuearticles values(VL); was used in the same manner as SRC-MUG-SMAC, only 16 insert ignore into journalissuearticles values(1.41%); of the 1130 colonies remained typical. In this procedure, no biochemical test was required for further identification. The use of an SRC-MUG-SMAC plate immediately after the colony selection step appeared to be more discriminative than the addition of these sugars and MUG to the primary isolation media. As a result, the testing of presumptive E. coli O157 colonies using a differential agar plate including MUG and 3 insert ignore into journalissuearticles values(or more); sugars that are not fermented by this organism is a rapid, easy, precise and relatively inexpensive isolation procedure, and it is particularly ideal for use in routine screening laboratories.
Keywords : E coli O157, salicin, rhamnose, cellobiose, MUG