An Evaluation of DNA-Based Methodologies for SubtypingSalmonella

Abstract

Bacteria of the genus Salmonella are major human and animal pathogens worldwide, with over 2000 serotypes. Although most authorities agree that there are only one or two true species of Salmonella, serotypes are accepted as pseudo-species. In addition, although serotype identification is important, without additional subtyping, serotyping has limited usefulness for epidemiology as three serotypes (S. typhimurium, S. enteriditis, and S. heidelberg) account for 50% of human infections worldwide. The purpose of this review is to evaluate different methods of DNA typing and fingerprinting of Salmonella strains and to report the most important epidemiological and phylogenetic discoveries that have been made using these methods. These include plasmid analysis (plasmid profiles and plasmid fingerprints, restriction fragment length polymorphism (RFLP) analysis, and polymerase chain reaction (PCR) fingerprinting).Plasmids are common but not universal in Salmonella isolates and can be used to discriminate isolates through plasmid profiles or restriction digests of plasmid DNA. They have been used with some success to subtype some serotypes. The correlation, however, is not always perfect. RFLP fingerprinting has also been used to subtype serotypes. Specifically, the IS200 insertion sequence has been used to probe restriction digests of chromosomal DNA. Probes derived from 16S sequences have been used similarly in 'ribotyping' studies but with less success. RFLP fingerprinting has been used in both phylogenetic and epidemiology studies of Salmonella and is considered to be a more stable and reliable method than plasmid analysis. PCR fingerprinting techniques, including arbitrarily primed PCR (AP PCR), repetitive sequence (REP) PCR and restriction digests of PCR-amplified 16S rDNA sequences have also been used to discriminate between Salmonella serotypes. The success of PCR methods is variable and depends on specific primers utilized. Overall, many fingerprinting techniques can discriminate between isolates but are often not successful in subtyping serotypes.

Μοριακή Ανάλυση Και Εξέλιξη Γονιδίων Παγοπυρήνωσης

“…Επομένως, αυτό το ζεύγος εκκινητών επιτρέπει την ενίσχυση αλληλουχιών 16S rDNA από τα περισσότερα βακτήρια (Weisburg et al, 1991 (Versalovic et al, 1991, de Bruijn, 1992, Louws et al, 1994, Burr et al, 1997, Lanoot et al, 2004, Cesaris et al, 2007 Στην παρούσα εργασία χρησιμοποιήθηκαν οι εκκινητές: α) ERIC1R: 5΄-ATGTAAGCTCCTGGGGATTCAC-3΄…”

“…Τέλος, το στέλεχος αυτό εμφανίζει ορισμένα χαρακτηριστικά του P. (Louws et al, 1994, Weingart and Volksch, 1997, Little et al, 1998, Vicente et al, 2007. Στην παρούσα εργασία χρησιμοποιήθηκαν εκκινητές που στοχεύουν στις ERIC και ΒΟΧ επαναλαμβανόμενες αλληλουχίες μεταξύ των γονιδίων, οι οποίες έχουν ανιχνευθεί στο γονιδίωμα αρκετών βακτηρίων (Versalovic et al, 1991, de Bruijn, 1992, Burr et al, 1997, Lanoot et al, 2004, Cesaris et al, 2007 ανάμεσά τους και μέλη του γένους Pseudomonas (Louws et al, 1994). (Hirano and Upper, 1995).…”