Enteritidis PT4 P125109 [27] which encodes two type I restriction/modification systems. All of these genes were not detected in the Kenyan S. Enteritidis isolate AF3176 and partially detected in isolate 47/03, which lacks one of the restriction enzyme subunits. In addition to variation in genes found in large clusters in S. Enteritidis PT4 P125109 there was also variation in genes found as https://www.selleckchem.com/products/jq1.html singletons (summarised in Tables 3 and 4). Of note is the absence of the gene ratB in
S. Enteritidis isolate 32/00. This gene is located within the CS54 genomic island in S. Typhimurium, a region that is important for intestinal persistence in a mouse model [47]. In S. Enteritidis PT4 P125109, the genomic island is maintained but ratB is a pseudogene, as it is in the sequenced strains of the host-adapted serovars S. Typhi and S. Gallinarum. Variation in plasmid-encoded genes Besides chromosomal genes, the microarray incorporated genes found on Salmonella virulence plasmids from serovars Enteritidis, Gallinarum, Typhimurium and plasmids, pHCM1 and pHCM2, from the multi-drug resistant S. Typhi strain CT18. Five Uruguayan isolates, 2 from food (206/99
and 32/02) and 3 from human disease (130/99, 199/02 and 214/02), lack the characteristic S. Enteritidis virulence plasmid. This was confirmed by attempts to purify the plasmid (Table 2). Two other Uruguayan isolates, 92/05 and 132/99, exhibited divergence in more than 30 genes and isolates 57/94 and 49/98 diverged in 15 genes found within the plasmid of S. Enteritidis PT4 GSK2245840 in vitro P125109 (see Table 2 and Figure 2). Included in the genes predicted as absent or divergent are the spv genes, the pef fimbrial operon as well as repA (DNA replication) and rsdB (resolvase). Of note, isolates from 92/05 and 132/99 also lack the few tra genes remaining in S. Enteritidis PT4 P125109. Figure 2 Graphical representation of the 57 genes from the Salmonella virulence plasmid as found in isolates that showed differences in plasmid content by CGH. In blue, genes present in the S. Enteritidis PT4 P125109 virulence
plasmid and predicted as absent in the test strain. In white, genes present in both reference and test strains. Despite the high degree of variability seen in these plasmids all had similar molecular weights when compared to that in S. Enteritidis PT4 P125109 (data not shown), suggesting potential divergence in gene sequence or acquisition of novel genes. However none of the isolates with high variation in plasmid gene content showed a positive signal for non-S. Enteritidis plasmid features included in the array, suggesting that they may harbour sequence divergence or novel sequences. In fact the only isolate showing a positive signal for non-S. Enteritidis plasmid features was the Kenyan S. Enteritidis isolate AF3353 which harbours the complete S.