Epidemiology and Infection

Salmonella

Optical genetic mapping defines regions of chromosomal variation in serovars of S. enterica subsp. enterica of concern for human and animal health

M. P. SAUNDERSa1a2, G. WUa1, M. ABUOUNa1, Z. PANa1a2, M. ANJUMa1 and M. J. WOODWARDa1 c1

a1 Department of Food and Environmental Safety (FES), Veterinary Laboratories Agency (Weybridge), Addlestone, Surrey, UK

a2 School of Biological Sciences, Royal Holloway, University of London, Egham, Surrey, UK

SUMMARY

Infections involving Salmonella enterica subsp. enterica serovars have serious animal and human health implications; causing gastroenteritis in humans and clinical symptoms, such as diarrhoea and abortion, in livestock. In this study an optical genetic mapping technique was used to screen 20 field isolate strains from four serovars implicated in disease outbreaks. The technique was able to distinguish between the serovars and the available sequenced strains and group them in agreement with similar data from microarrays and PFGE. The optical maps revealed variation in genome maps associated with antimicrobial resistance and prophage content in S. Typhimurium, and separated the S. Newport strains into two clear geographical lineages defined by the presence of prophage sequences. The technique was also able to detect novel insertions that may have had effects on the central metabolism of some strains. Overall optical mapping allowed a greater level of differentiation of genomic content and spatial information than more traditional typing methods.

(Accepted August 10 2010)

(Online publication September 22 2010)

Correspondence:

c1 Author for correspondence: Dr M. J. Woodward, Department of Food and Environmental Safety (FES), Veterinary Laboratories Agency (Weybridge), Addlestone, Surrey, KT15 3NB, UK. (Email: m.j.woodward@vla.defra.gsi.gov.uk)

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