Characterisation of ropy slime-producing Lactobacillus sakei using repetitive element sequence-based PCR

Abstract

Eighteen previously characterised Lactobacillus sakei strains exhibiting varying slime production capabilities in vacuum-packaged meat products were analysed using repetitive element sequence-based PCR (rep-PCR). The single primers BOXA1R and RW3A and the primer pair REP1R-Dt and REP2R-Dt were evaluated for their applicability in L. sakei genotyping. The five different patterns produced by RW3A were the least useful, with the discriminatory power equal to ribotyping. BOXA1R and REP–primer pair both produced six different banding patterns and the combination of these results yielded seven different rep-types. Rep-PCR was concluded to have approximately the same discriminatory power as randomly amplified polymorphic DNA (RAPD) analysis, but was inferior to pulsed-field gel electrophoresis (PFGE). However, if the results of rep-PCR and RAPD were combined, the discrimination was comparable to PFGE, with the exception that within Ribogroup I non-slime-producing strains were indistinguishable from weak slime producers. It was concluded that the combination of the two PCR-based typing techniques, rep-PCR and RAPD, would be a valuable tool in large scale contamination studies at meat processing plants, since results can be obtained rapidly with fewer isolates needing further analysis by PFGE.