Source Attribution Study of Sporadic Salmonella Derby Cases in France

Abstract

Salmonella enterica subsp. enterica serovar Derby is one of the most frequent causes of gastroenteritis in humans. In Europe, this pathogen is one of the top five most commonly reported serovars in human cases. In France, S. Derby has been among the ten most frequently isolated serovars in humans since the year 2000. The main animal hosts of this serovar are pigs and poultry, and white meat is the main source of human contamination. We have previously shown that this serovar is polyphyletic and that three distinct genetic lineages of S. Derby cohabit in France. Two of them are associated with pork and one with poultry. In this study, we conducted a source attribution study based on single nucleotide polymorphism analysis of a large collection of 440 S. Derby human and non-human isolates collected in 2014-2015, to determine the contribution of each lineage to human contamination. In France, the two lineages associated with pork strains, and corresponding to the multilocus sequence typing (MLST) profiles ST39-ST40 and ST682 were responsible for 94% of human contaminations. Interestingly, the ST40 profile is responsible for the majority of human cases (71%). An analysis of epidemiologic data and the structure of the pork sector in France allowed us to explain the spread and the sporadic pattern of human cases that occurred in the studied period.

Genome-Wide Identification of Genes Involved in Acid Stress Resistance of Salmonella Derby

“…The stomach's acidic environment can be considered the first barrier against foodborne pathogens, and several organic acids can be produced in the stomach, including lactic, acetic, propionic, and butyric acid [12]. Recent epidemiological studies have demonstrated that S. Derby has become one of the most prevalent Salmonella serotypes in pigs and humans [1][2][3]. As a foodborne pathogen, S. Derby also needs to resist acid stress in the stomach during the infection process, before it can colonize the ileum and cecum [15].…”

“…Recent epidemiological studies have demonstrated that S . Derby has become one of the most prevalent Salmonella serotypes in pigs and humans [ 1 , 2 , 3 ]. As a foodborne pathogen, S .…”

“…Salmonella Derby is one of the most prevalent Salmonella serotypes worldwide, and can be isolated from pigs, poultry, and humans, particularly children and the elderly [1][2][3]. In Europe, S. Derby is the 5th most frequently identified serotypes in humans [4].…”

“…In France, the S. Derby strains isolated from pork and poultry were spread across four different genetic lineages corresponding to four multi-locus sequence types (MLST): ST39, ST40, ST71, and ST682 [5]. The S. Derby strains isolated from pork samples were mainly affiliated with ST40, and the ST40 strains was responsible for 94% of human infections [2]. In China, S. Derby was also identified as one of the common serotypes in pigs and humans, with the strains divided into two MLSTs: ST71 and ST40 [6].…”

“…The S . Derby strains isolated from pork samples were mainly affiliated with ST40, and the ST40 strains was responsible for 94% of human infections [ 2 ]. In China, S .…”