Towards the development of a DNA-sequence based approach to serotyping of <it>Salmonella enterica</it>

• Main Authors: Logan Julie MJ, Gharbia Saheer E, Peters Tansy M, Mortimer Chloe KB, Arnold Catherine
• Format: Article
• Language: English
• Published: BMC 2004-08-01
• Series: BMC Microbiology
• Online Access: http://www.biomedcentral.com/1471-2180/4/31

<p>Abstract</p> <p>Background</p> <p>The <it>fliC </it>and <it>fljB </it>genes in <it>Salmonella </it>code for the phase 1 (H1) and phase 2 (H2) flagellin respectively, the <it>rfb </it>cluster encodes the majority of enzymes for polysaccharide (O) antigen biosynthesis, together they determine the antigenic profile by which <it>Salmonella </it>are identified. Sequencing and characterisation of <it>fliC </it>was performed in the development of a molecular serotyping technique.</p> <p>Results</p> <p><it>FliC </it>sequencing of 106 strains revealed two groups; the g-complex included those exhibiting "g" or "m,t" antigenic factors, and the non-g strains which formed a second more diverse group. Variation in <it>fliC </it>was characterised and sero-specific motifs identified. Furthermore, it was possible to identify differences in certain H antigens that are not detected by traditional serotyping. A rapid short sequencing assay was developed to target serotype-specific sequence motifs in <it>fliC</it>. The assay was evaluated for identification of H1 antigens with a panel of 55 strains.</p> <p>Conclusion</p> <p><it>FliC </it>sequences were obtained for more than 100 strains comprising 29 different H1 alleles. Unique pyrosequencing profiles corresponding to the H1 component of the serotype were generated reproducibly for the 23 alleles represented in the evaluation panel. Short read sequence assays can now be used to identify <it>fliC </it>alleles in approximately 97% of the 50 medically most important <it>Salmonella </it>in England and Wales. Capability for high throughput testing and automation give these assays considerable advantages over traditional methods.</p>