Reference collection of strains of the Salmonella typhimurium complex from natural populations

Beltran, P.; Plock, S. A.; Smith, Noel H.; Whittam, Thomas S.; Old, D. C.; Selander, Robert K.

doi:10.1099/00221287-137-3-601

Cited by 131 publications

(94 citation statements)

References 5 publications

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“…Comparison of the serotype Typhimurium LT2 genome with that of the pigeon isolate phage types DT2 and DT99 by microarray analysis supports several lines of previously published work. First, the results of the microarray analysis showed that the genetic differences between these isolates are small, and they confirmed previous results that different isolates of the same serotype are very closely related (3,4). A recent pulsed-field gel electrophoretic analysis of 38 DT99 pigeon isolates and 18 isolates from other species indicated that the DT99 isolates examined were essentially clonal (24).…”

Section: Vol 186 2004 Differences Between Serotype Typhimurium Isolsupporting

confidence: 69%

“…Serotype Typhimurium consists of a collection of isolates that are more closely related to each other than they are to other S. enterica serotypes (3,4) and are distinguishable from each other by phage typing and other epidemiologic typing methods (27). Epidemiologic evidence indicates that certain phage types of serotype Typhimurium have a narrow host range and are very frequently isolated from particular host species and rarely from other mammals or birds.…”

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Host Restriction of Salmonella enterica Serotype Typhimurium Pigeon Isolates Does Not Correlate with Loss of Discrete Genes

et al. 2004

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The definitive phage types (DT) 2 and 99 of Salmonella enterica serotype Typhimurium are epidemiologically correlated with a host range restricted to pigeons, in contrast to phage types with broader host ranges such as epidemic cattle isolates (DT104 and DT204). To determine whether phage types with broad host range possess genetic islands absent from host-restricted phage types, we compared the genomes of four pigeon isolates to serotype Typhimurium strain LT2 using a DNA microarray. Three of the four isolates tested caused fluid accumulation in bovine ligated ileal loops, but they had reduced colonization of liver and spleen in susceptible BALB/c mice and were defective for intestinal persistence in Salmonella-resistant CBA mice. The genomes of the DT99 and DT2 isolates were extremely similar to the LT2 genome, with few notable differences on the level of complete individual genes. Two large groups of genes representing the Fels-1 and Fels-2 prophages were missing from the DT2 and DT99 phage types we analyzed. One of the DT99 isolates examined was lacking a third cluster of five chromosomal genes (STM1555 to -1559). Results of the microarray analysis were extended using Southern analysis to a collection of 75 serotype Typhimurium clinical isolates of 24 different phage types. This analysis revealed no correlation between the presence of Fels-1, Fels-2, or STM1555 to -1559 and the association of phage types with different host reservoirs. We conclude that serotype Typhimurium phage types with broad host range do not possess genetic islands influencing host restriction, which are absent from the host-restricted pigeon isolates.

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Section: Vol 186 2004 Differences Between Serotype Typhimurium Isolsupporting

confidence: 69%

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confidence: 99%

Host Restriction of Salmonella enterica Serotype Typhimurium Pigeon Isolates Does Not Correlate with Loss of Discrete Genes

et al. 2004

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“…The name "virulence antigen" notwithstanding, a casual relationship of this polysaccharide to virulence has not been convincingly demonstrated, even for S. typhi, in which it has been extensively studied (12,33). When tested in the mouse model, several Vi-positive strains of S. dublin have been found to be no more virulent than Vi-negative strains (6,29 typhimurium (4,5). Table 4.…”

Section: Methodsmentioning

confidence: 99%

Molecular evolutionary genetics of the cattle-adapted serovar Salmonella dublin

Selander

Smith

et al. 1992

J Bacteriol

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An electrophoretic analysis of allelic variation at 24 enzyme loci among 170 isolates of the serovar Salmonella dublin (serotype 1,9,12[ViJ:g, identified three electrophoretic types (Du 1, Du 3, and Du 4), marking three closely related clones, one of which (Du 1) is globally distributed and was represented by 95% of the randomly selected isolates. All but 1 of 114 nonmotile isolates of serotype 1,9,12:-:-recovered from cattle and swine in the United States were genotypically Du 1. The virulence capsular polysaccharide (Vi antigen) is confined to clone Du 3, which apparently is limited in distribution to France and Great Britain. For all 29 isolates of Du 3, positive signals were detected when genomic DNA was hybridized with a probe specific for the ViaB region, which contains the structurally determinant genes for the Vi antigen; and 23 of these isolates had been serologically typed as Vi positive. In contrast, all 30 isolates of Du 1 tested with the ViaB probe were negative.These findings strongly suggest that the ViaB genes were recently acquired by S. dublin via horizontal transfer and additive recombination. The clones of S. dublin are closely similar to the globally predominant clone (En 1) of Salmonella enteritidis (serotype 1,9,12:g,m:-) in both multilocus enzyme genotype and nucleotide sequence of thefliC gene encoding phase 1 flagellin. Comparative sequencing offliC has revealed the molecular genetic basis for expression of the p and m flagellar epitopes by which these serovars are distinguished in the Kauffmann-White serological scheme of classification.The serovar Salmonella dublin (serotype 1,9,12 [Vi]:g, p:-) is most frequently recovered from cattle, to which it is regarded as strongly host adapted (7, 34), although it has shown a tendency to spread to swine and occasionally infects sheep and other domesticated animals (27, 48). In cattle, S. dublin causes enteric fever in both calves and adults and also induces abortion by invading the fetal blood system; and the frequent development of a carrier state, including a condition in which cows shed bacteria in their milk (40), provides the main reservoir of infection (10,46,54). Human infections with S. dublin, which are severe and may be fatal, especially in AIDS patients and other immunocompromised persons (8,19,26,53), are usually associated with the consumption of unpasteurized dairy products (13,15).An unusual feature of variation in S. dublin is that some strains express the virulence capsular antigen (Vi antigen), an acetylated polymer of galactosaminuronic acid that forms a coat on the external surface of the bacterial cell (1, 14, 25). The only other bacteria known to express this polysaccharide are the distantly related serovars Salmonella typhi and Salmonella paratyphi C (11,38,44) and a few strains of Citrobacterfreundii (12,45). For these bacteria, it has been established that the genes determining the structure of the Vi antigen are located in the ViaB region of the chromosome (20,22,44,45).Strains of S. dublin are normally motile and mono...

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“…Inversions with endpoints in the seven copies of the rrn operons are common in S. typhimurium (15) and E. coli (17); the frequency of inversions at other sites varies from low to undetectable (18). This high frequency of rearrangements in culture, combined with the stability of the chromosome through evolution, indicates that cells with rearrangements are strongly selected of which has a cleavage site for the endonuclease I-CeuI (6,7). The seven I-Ceul fragments are in the order ABCDEFG.…”

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confidence: 99%

Highly plastic chromosomal organization in Salmonella typhi.

Liu

Sanderson

1996

Proc. Natl. Acad. Sci. U.S.A.

159

124

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Gene order in the chromosomes of Escherichia coli K-12 and Salmonella typhimurium LT2, and in many other species of Salmonella, is strongly conserved, even though the genera diverged about 160 million years ago. However, partial digestion of chromosomal DNA ofSalmonella typhi, the causal organism of typhoid fever, with the endonuclease I-Ceul followed by separation of the DNA fragments by pulsed-field gel electrophoresis showed that the chromosomes of independent wild-type isolates of S. typhi are rearranged due to homologous recombination between the seven rrn genes that code for ribosomal RNA. The order of genes within the I-Ceul fragments is largely conserved, but the order of the fragments on the chromosome is rearranged. Twenty-one different orders of the I-CeuI fragments were detected among the 127 wild-type strains we examined. Duplications and deletions were not found, but transpositions and inversions were common. Transpositions of I-CeuI fragments into sites that do not change their distance from the origin of replication (oriC) are frequently detected among the wild-type strains, but

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Reference collection of strains of the Salmonella typhimurium complex from natural populations

Cited by 131 publications

References 5 publications

Host Restriction of Salmonella enterica Serotype Typhimurium Pigeon Isolates Does Not Correlate with Loss of Discrete Genes

Host Restriction of Salmonella enterica Serotype Typhimurium Pigeon Isolates Does Not Correlate with Loss of Discrete Genes

Molecular evolutionary genetics of the cattle-adapted serovar Salmonella dublin

Highly plastic chromosomal organization in Salmonella typhi.

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