The BOX-rep-APD - A rapid and efficient method for the identification and differentiation of listeria

The BOX-rep-APD is a new, relatively simple and fast technique for genotypi ng bacteria. The polymerase chain reaction (PCR) is used to amplify DNA str etches between repetitive (rep) genetic elements of the bacterial genome in the presence of the BOX primer. The random distribution of these elements within the genome results in a number of amplified DNA fragments of differe nt length which, after electrophoretical separation, give a characteristic banding pattern (fingerprint). We show here that BOX-rep-APD delivers chara cteristic genetic fingerprints for different Listeria species. L. monocytog enes could be separated into two main clusters. Within the species L. innoc ua four clusters were obtained. L. welshimeri showed three BOX-rep-APD prof iles, while the investigated strains of L. seeligeri were quite similar amo ng each other. According to the results obtained so far the BOX-rep-APD see ms to be well suited for the identification of listeria. With an appropriat e set of known BOX-rep-APD profiles available, unknown isolates can be assi gned clearly to one of the described species. In addition, within individua l species different genotypes can be identified. Thus, the BOX-rep-APD can also give hints for epidemiological questions or strain specific contaminat ions in food and food production plants.