Evaluation of the use of CRISPR loci for discrimination of subsp. serovar Enteritidis strains recovered in Canada and comparison with other subtyping methods.

subsp. serovar Enteritidis remains one of the most important foodborne pathogens worldwide. To minimise its public health impact when outbreaks of the disease occur, timely investigation to identify and recall the contaminated food source is necessary.

An Unusual Enteritidis Strain Carrying a Modified Virulence Plasmid Lacking the Gene Represents a Geographically Widely Distributed Lineage.

This study identifies a strain of subspecies serovar Enteritidis that harbors a highly unusual virulence plasmid. During the characterisation of a group of Enteritidis isolates, 10 isolates recovered from Canadian duck production facilities, of which seven were phage type 9b and three were closely related atypical phage types, failed detection by a PCR targeting the gene, a marker located on the virulence plasmid often employed for identification of this serovar. Comparison to + isolates by several standard genetic typing tools, further revealed their distinctive genomic makeup.

Evaluation of a Multiplex PCR Assay for the Identification of Salmonella Serovars Enteritidis and Typhimurium Using Retail and Abattoir Samples.

A multiplex PCR was developed to identify the two most common serovars of Salmonella causing foodborne illness in Canada, namely, serovars Enteritidis and Typhimurium. The PCR was designed to amplify DNA fragments from four Salmonella genes, namely, invA gene (211-bp fragment), iroB gene (309-bp fragment), Typhimurium STM 4497 (523-bp fragment), and Enteritidis SE147228 (612-bp fragment). In addition, a 1,026-bp ribosomal DNA (rDNA) fragment universally present in bacterial species was included in the assay as an internal control fragment.

Draft Genome Sequences of Two Strains of Serovar Typhimurium Displaying Different Virulence in an Experimental Chicken Model.

serovar Typhimurium strains 22495 and 22792, obtained from wild birds, were found to display different virulence attributes in an experimental chicken model. Closed genome sequences were assembled after sequencing with the Roche 454 and Illumina MiSeq platforms. An additional plasmid was present in the more virulent strain 22495.

Microplate fluorescence assay for the quantification of double stranded DNA using SYBR Green I dye.

A high-throughput, 96-well microplate fluorescence assay (MFA) was developed for DNA quantification using the double-stranded DNA-binding dye SYBR Green I. Samples mixed with SYBR Green I in the wells of a microtiter plate produced fluorescence in proportion with DNA concentration which was measured using a fluorescence plate reader. The performance characteristics of the assay were compared with spectrophotometric quantification based on ultraviolet absorption and the Hoefer DyNA Quant assay utilizing the fluorescent dye, Hoechst 33258.