Metabolic Proteins Expression Up-Regulated in Blood-Borne Extensively Drug-Resistant Salmonella Typhi Isolates from Pakistan

: In the undertaken study, proteomics alterations of blood-borne XDR Typhi isolated from Pakistan were investigated using mass spectrometry. : MDR and XDR Typhi total protein lysates were fractionated, digested, and processed for nanoflow LC-LTQ- analysis. : Among the 1267 identified proteins, 37 were differentially regulated, of which 28 were up-regulated, and 9 were down-regulated in XDR Typhi as compared to MDR Typhi. Based on the functional annotation, proteins found up-regulated are involved mainly in metabolic pathways (ManA, FadB, DacC, GpmA, AphA, PfkB, TalA, FbaB, OtsA, 16504242), the biosynthesis of secondary metabolites (ManA, FadB, GlpB, GpmA, PfkB, TalA, FbaB, OtsA), microbial metabolism in diverse environments (FadB, GpmA, PfkB, NfnB, TalA, FbaB), and ABC transporters (PstS, YbeJ, MglB, RbsB, ArtJ). Proteins found down-regulated are involved mainly in carbon metabolism (FadB, GpmA, PfkB, FalA, FbaB) and the biosynthesis of amino acids (GpmA, PfkB, TalA, FbaB). Most of the identified differential proteins were predicted to be antigenic, and matched with resistome data. : A total of 28 proteins were up-regulated, and 9 were down-regulated in XDR Typhi. Further characterization of the identified proteins will help in understanding the molecular signaling involved in the emergence of XDR . Typhi.