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Dona Wijetunge

Insights from sequencing of Escherichia coli RS218 genome in identifying potential virulence traits common to meningitic and other extra-intestinal pathogenic Escherichia coli

Wijetunge, D.S.S., Katani, R., Kapur, V., and Kariyawasam, S.

Escherichia coli RS218 is the prototypic strain of neonatal meningitis causing Escherichia coli (NMEC) recovered from the cerebrospinal fluid of an infected neonate. This strain of NMEC  has been used in many studies relevant to NMEC pathogenesis. However, its complete genome sequence is not available hampering the efforts to fully elucidate NMEC virulence and pathogenesis. In this study, the entire genome of E. coli RS218 was sequenced. Analysis of the genome revealed a circular chromosome of 5.087 Mb in size and a 114-kbp plasmid (pRS218) both with an average G+C content of 50.6%. The E. coli RS218 chromosome contains 4,658 coding sequences, 88 transfer RNAs, 22 ribosomal RNAs (rRNA), one Clustered Regularly Interspaced Short Palindromic Repeats array, and five noncoding rRNAs. This genome was compared with eight other genomes of extra intestinal pathogenic E. coli and the laboratory strain of E. coli, K12. Complete sequence analysis of E. coli RS218 revealed 98% similarity to cystitis causing E. coli strain UTI89. A total of 51 genomic islands (GIs) were present in E. coli RS218 which were absent from E. coli K12. Out of these 51 GIs, 2 GIs were common to all extra-intestinal pathogenic E. coli whereas 16 were present in all NMEC strains studied.  The GIs shared by all NMEC encode for several sugar uptake pathways, an acid tolerance operon, iron uptake systems, and putative adhesins and invasins which may contribute to NMEC pathogenesis.