Genetic diversity within Lactobacillus sakei and Lactobacillus curvatus and design of PCR primers for its detection using randomly amplified polymorphic DNA

The genotypic and phenotypic diversity among isolates of the Lactobacillus curvatus/Lactobacillus graminis/Lactobacillus sakei group was evaluated by comparing RAPD data and results of biochemical tests, such as hydrolysis of arginine, a-lactate production, melibiose and xylose fermentation, and the presence of haem-dependent catalase. Analyses were applied to five type st rains and to a collection of 16S isolates previously assigned to L. sakei o r L. curvatus. Phenotypic and RAPD data were compared with each other and w ith previous DNA-DNA hybridization data. The phenotypic and genotypic separ ation between L. sakei, L. curvatus and L. graminis was clear, and new insi ghts into the detailed structure within L. sakei and L. curvatus were obtai ned. Individual strains could be typed by RAPD and, after the elimination o f similar or identical isolates, two sub-groups in both L. curvatus and L. sakei were defined. The presence or absence of catalase activity further di stinguished the two L. curvatus sub-groups. By cloning and sequencing speci fic RAPD products, pairs of PCR primers were developed that can be used to specifically detect L. curvatus, L. sakei and each of the L. sakei sub-grou ps.