Rapid detection of Listeria monocytogenes in food using culture enrichment combined with real-time PCR.

A rapid method for the detection of Listeria monocytogenes in foods combining culture enrichment and real-time PCR was compared to the ISO 11290-1 standard method. The culture enrichment component of the rapid method is based on the ISO standard and includes 24h incubation in half-Fraser broth, 4h incubation in Fraser broth followed by DNA extraction and real-time PCR detection of the ssrA gene of L. monocytogenes. An internal amplification control, which is co-amplified with the same primers as the L. monocytogenes DNA, was also included in the assay. The method has a limit of detection of 1-5CFU/25g food sample and can be performed in 2 working days compared to up to 7days for the ISO standard. A variety of food samples from retail outlets and food processing plants (n=175) and controls (n=31) were tested using rapid and conventional methods. The rapid method was 99.44% specific, 96.15% sensitive and 99.03% accurate when compared to the standard method. This method has the potential to be used as an alternative to the standard method for food quality assurance providing rapid detection of L. monocytogenes in food

Oceanivirga salmonicida gen. nov., sp. nov., a member of the leptotrichiaceae isolated from atlantic salmon (salmo salar)

A pleomorphic, Gram-negative, rod-shaped, indole-, oxidase- and catalase-negative, non-spore-forming, non-motile bacterium was originally isolated in 1992 from moribund, seawater farmed Atlantic salmon with multifocal tissue necrosis. Strain AVG 2115(T) displayed considerable similarities with Streptobacillus moniliformis, one of the two etiological agents of rat bite fever, and has been stored as Streptobacillus sp. NCIMB 703044(T). On the basis of 16S rRNA gene sequence analyses, this strain displayed >99 % sequence similarities with uncultured bacterial clones from the digestive tracts of marine mammals, followed by Sneathia sanguinegens CCUG 41628(T) (92.7 %), 'Sneathia amnii' Sn35 (92.5 %), Caviibacter abscessus CCUG 39713(T) (92.2 %), Streptobacillus rattiOGS16(T) (91.3 %), Streptobacillus notomytis AHL 370-1(T) (91.2 %), S. moniliformis DSM 12112(T) (91.0 %), Streptobacillus fells 131000547(T) (90.9 %) and Streptobacillus hongkongensis DSM 26322(T) (89.7 %). Sequence similarities to all other taxa were below 89 %. Phylogenetic analysis for strain NCIMB 703044(T) revealed highly similar results for gyrB, groEL and recA nucleotide and deduced amino acid sequence analyses independent of the employed treeing method. Average nucleotide identities (ANI) for complete genomes ranged from 66.00 % to 72.08 % between strain NCIMB 703044(T) and the type strains of Sebaldella termitidis, Leptotrichia buccalis, Streptobacillus moniliformis, Sneathia sanguinegens and Caviibacter abscessus. Chemotaxonomic and physiological data of strain NCIMB 703044(t) were in congruence with closely related members of the family Leptotrichiaceae, represented by highly similar enzyme profiles and fatty acid patterns. MALDI-TOF MS analysis was capable to clearly discriminate strain NCIMB 703044(T) from all currently described taxa of the family Leptotrichiaceae. On the basis of these data we propose the novel taxon Oceanivirga salmonicida gen. nov. sp. nov. with the type strain AVG 2115(T) (= NCIMB 7030441(T)) (=DSM 101867(T)). The G+C content is 25.40 %, genome size is 1.77 Mbp

Oceanivirga salmonicida gen. nov., sp. nov., a member of the leptotrichiaceae isolated from atlantic salmon (salmo salar)

A pleomorphic, Gram-negative, rod-shaped, indole-, oxidase- and catalase-negative, non-spore-forming, non-motile bacterium was originally isolated in 1992 from moribund, seawater farmed Atlantic salmon with multifocal tissue necrosis. Strain AVG 2115(T) displayed considerable similarities with Streptobacillus moniliformis, one of the two etiological agents of rat bite fever, and has been stored as Streptobacillus sp. NCIMB 703044(T). On the basis of 16S rRNA gene sequence analyses, this strain displayed >99 % sequence similarities with uncultured bacterial clones from the digestive tracts of marine mammals, followed by Sneathia sanguinegens CCUG 41628(T) (92.7 %), \u27Sneathia amnii\u27 Sn35 (92.5 %), Caviibacter abscessus CCUG 39713(T) (92.2 %), Streptobacillus rattiOGS16(T) (91.3 %), Streptobacillus notomytis AHL 370-1(T) (91.2 %), S. moniliformis DSM 12112(T) (91.0 %), Streptobacillus fells 131000547(T) (90.9 %) and Streptobacillus hongkongensis DSM 26322(T) (89.7 %). Sequence similarities to all other taxa were below 89 %. Phylogenetic analysis for strain NCIMB 703044(T) revealed highly similar results for gyrB, groEL and recA nucleotide and deduced amino acid sequence analyses independent of the employed treeing method. Average nucleotide identities (ANI) for complete genomes ranged from 66.00 % to 72.08 % between strain NCIMB 703044(T) and the type strains of Sebaldella termitidis, Leptotrichia buccalis, Streptobacillus moniliformis, Sneathia sanguinegens and Caviibacter abscessus. Chemotaxonomic and physiological data of strain NCIMB 703044(t) were in congruence with closely related members of the family Leptotrichiaceae, represented by highly similar enzyme profiles and fatty acid patterns. MALDI-TOF MS analysis was capable to clearly discriminate strain NCIMB 703044(T) from all currently described taxa of the family Leptotrichiaceae. On the basis of these data we propose the novel taxon Oceanivirga salmonicida gen. nov. sp. nov. with the type strain AVG 2115(T) (= NCIMB 7030441(T)) (=DSM 101867(T)). The G+C content is 25.40 %, genome size is 1.77 Mbp