Molecular epidemiology and population genetics of Salmonella subspecies diarizonae in sheep in Norway and Sweden

Abstract

Fifty-four isolates of Salmonella enterica subsp. diarizonae (IIIb) in Norway, Sweden, England, the United States, France and Australia were characterized by pulsed-field gel electrophoresis (PFGE). This study focuses on serovar 61:k:1,5,(7) [S. IIIb 61:k:1,5,(7)] isolated from sheep. Digestion of the bacterial DNA with restriction enzyme XhaI yielded 15 distinct PFGE profiles comprising 12-16 fragments in the range 48.5-630.5 kbp. Four different profiles were identified in Norwegian sheep isolates and a single profile in Swedish isolates. The spatial and temporal distribution of profiles is discussed.

Nationwide pseudo-outbreak of Salmonella enterica ssp. diarizonae, France

“…The PFGE subtyping method was very discriminative for this serotype, as reported previously in Norwegian and Swedish sheep [6].…”

“…Thorough investigations revealed that nine of the ten isolates had grown on sheep blood agar from the same manufacturer and that the batch number was similar for three cases. Moreover, SIIIb 61:k:1,5,7 infections in European sheep flocks had previously been described [6].…”

“…B. henselae is found in cats, and cat fleas are well established vectors for B. henselae transmission among cats [4]. Infection of humans seems to occur via cat scratches or bites, however, transmission by other arthropods, in particular ticks, is suggested [5,6].…”

High prevalence of Salmonella enterica subsp. diarizonae in tonsils of sheep at slaughter

“…diarizonae 61:k:1,5,(7) strains of which 17 were found in only one animal. Alvseike et al (2004) found only 15 distinct XbaI patterns among 54 S. enterica subsp. diarizonae belonging to different serotypes.…”

Subspecies IIIa and IIIb Salmonellae Are Defective for Colonization of Murine Models of Salmonellosis Compared to Salmonella enterica subsp. I Serovar Typhimurium

“…Subspecies IIIa and IIIb are considered reptile associated, and they colonize the reptilian intestinal tract asymptomatically and are excreted in feces (6,11,49,58). Both subspecies IIIa and IIIb can cause disease in various warm-blooded vertebrates, including humans, domestic poultry, sheep, wild birds, and cats (1,2,18,50). Subspecies IIIa and IIIb are observed as the cause of disease in humans, especially in the young and in immunocompromised individuals.…”