Genome evolution and plasticity of Serratia marcescens, an important multidrug-resistant nosocomial pathogen.
Bottom Line: Naturally, it is found in many environmental niches, and is capable of infecting plants and animals.We further show that pSMC1 is most closely related to plasmids circulating in Pseudomonas species.Our data will provide a valuable basis for future studies on S. marcescens and new insights into the genetic mechanisms that underlie the emergence of pathogens highly resistant to multiple antimicrobial agents.
Affiliation: Interdisciplinary Research Organization, University of Miyazaki, JapanPresent address: Department of Animal and Grassland Sciences, Faculty of Agriculture, University of Miyazaki, Japan.Show MeSH
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Mentions: To extend the analysis of unique and shared genes between the two strains, we performed a clustering analysis of the SM39 and Db11 CDSs using an all-against-all BLASTP approach (outlined in supplementary fig. S1, Supplementary Material online). This showed that 3,970 genes (or gene families) were conserved in both strains with additional 860 SM39-specific and 728 Db11-specific genes (fig. 2A). Functional classification of these genes based on the Cluster of Orthologous Groups (COG) categories indicated that genes belonging to “category L (replication, recombination, and repair)” and “category V (defense mechanisms)” are more highly represented in SM39 than in Db11 (fig. 2B). These differences are largely attributable to the presence of more genes associated with lateral gene transfer in SM39 such as insertion sequence (IS) transposases and integrases (category L), and genes for restriction-modification systems and multidrug transport systems (category V). For example, SM39 carries a higher variety and number of IS elements: 18 compared with the 5 carried by Db11 (table 1). These IS elements were classified into 11 distinct types, nine of which represent novel IS elements. Eight types were found in SM39 and four in Db11, with only ISSe5 being shared by both isolates (supplementary table S3, Supplementary Material online). More prophages were also found in SM39 (seven) than in Db11 (only two), with none of the prophages and other integrative elements being shared by the two strains (table 1 and supplementary table S4, Supplementary Material online).Fig. 2.—
Affiliation: Interdisciplinary Research Organization, University of Miyazaki, JapanPresent address: Department of Animal and Grassland Sciences, Faculty of Agriculture, University of Miyazaki, Japan.