Vet. Res. 36 (2005) 267-288
DOI: 10.1051/vetres:2005005

Emergence of Salmonella epidemics: The problems related to Salmonella enterica serotyp Enteritidis and multiple antibiotic resistance in other major serotypes

Philippe Velge^a, Axel Cloeckaert^b and Paul Barrow<sup>c

a</sup>  Institut National de Recherche Agronomique, Centre de Tours-Nouzilly, UR 918, Pathologie Infectieuse et Immunologie, 37380 Nouzilly, France
^b  Institut National de Recherche Agronomique, Centre de Tours-Nouzilly, UR 086, BioAgresseurs, Santé, Environnement, 37380 Nouzilly, France
^c  Institute for Animal Health, Compton Lab, Newbury RG20 7NN, Berks, United Kingdom

(Received 9 June 2004; accepted 2 November 2004)

Abstract - Two major changes in the epidemiology of salmonellosis occurred in the second half of the 20th century: the emergence of food-borne human infections caused by S. Enteritidis and by multiple-antibiotic resistant strains of Salmonella. This review updates information on the S. Enteritidis pandemic and focuses on the emergence of Salmonella, carrying the SGI1 antibiotic resistance gene cluster, resistant to extended-spectrum cephalosporins, or resistant to fluoroquinolones. The factors responsible for the emergence of these Salmonella strains could be either of human origin or related to bacterial genome evolution. However, our increasing understanding of the molecular fluidity of the genome shows that any attempt to counteract bacteria results in further bacterial evolution or adaptation of other bacteria to take place in the new free ecological niche. In these conditions, we can ask who is faster: humans who want to eliminate bacterial pathogens or bacteria that continuously evolve to gain new niches.

Key words: Salmonella / emergence / antibiotic resistance / virulence / genome evolution

Corresponding author: Philippe Velge velge@tours.inra.fr

© INRA, EDP Sciences 2005