Multiplex Polymerase Chain Reaction amplification products shown following gel electrophoresis.

Lanes 1 and 12 contain HyperLadder V (Bioline), with the remaining lanes containing products derived from 6 ng genomic DNA from as shown. Internal amplification control (IAC) template DNA was included in all reactions. Templates were amplified in isolation (apart from universal inclusion of the IAC) or in combination as described in the figure using a 15-primer multiplex PCR. Codes used are as follows: SE, Salmonella enterica MISE807439; LM, Listeria monocytogenes CMCC2993; LW, Listeria welshimeri CMCC3366; LG, Listeria grayi CMCC3362. Patterns for L. seeligeri, L. murrayi, L. ivanovii and L. innocua were identical to that of L. welshimeri, and all patterns shown were representative of all other strains tested of the same species. Size standards are descirbed on the left of the figure in base pairs (bp), while PCR products are described on the right of the figure with both their name and size in bp. ² indicates the prs amplimer from Listeria grayi only, with ¹ denoting the corresponding product from all other Listeria species. Electrophoresis was performed on a 1.7% agarose gel at 70 volts for 1.5 hrs with EtBr, with 4 ul of each product loaded.