Preferential use of carbon central metabolism and anaerobic respiratory chains in porcine extraintestinal pathogenic Escherichia coli during bloodstream infection

Porcine extraintestinal pathogenic Escherichia coli delivers two serine protease autotransporters coordinately optimizing the bloodstream infection

“…Furthermore, inactivation of Vat PU-1 alone or Tsh PU-1 alone did not affect the bacterial survival in host blood, suggesting that these two SPATEs of strain PU-1 have obvious compensatory effects on each other, while they do not seem functionally redundant, as the encoding features of genes located in chromosome and plasmid may regulated by different mechanisms. Otherwise, the above analyses partially explain why we could not screen these two SPATEs as blood colonization factors in strain PU-1 through high-throughput technologies in previous studies ( Ma et al., 2020 ; Ma et al., 2021 ). Although these studies have identified the carbon central metabolism, anaerobic respiratory chains, de novo biosynthetic pathways of nucleotide, extracellular polysaccharide biosynthesis and iron uptake playing critical roles for heavy bacterial load within bloodstream, the underlying mechanisms of strain PU-1 escaping from the host immune clearance via the interaction with the blood components (including RBCs, leukocytes, lymphocytes, et al.)…”

“…Comparative analysis based on our previous transcriptome data ( Ma et al., 2020 ) found two special genes, FQU83_21385 (chromosome encoding) and FQU83_01245 (plasmid encoding), which encoded two serine protease autotransporters of enterobacteria (SPATEs), and showed the significant upregulation of more than 3 folds in animal blood but not in serum ( Figure 2A ). Phylogenetic analysis showed that the FQU83_21385 and FQU83_01245 belong to the class-2 of SPATEs ( Figure 2B ), and share highest sequence identities with the well-studied virulence factors Vat homologue of strain LF82 and Tsh homologue of strain APEC O1, respectively, thereby were redesignated as Vat PU-1 and Tsh PU-1 in strain PU-1.…”

“…PU-1 is an O2:K1 ExPEC strain causing acute sepsis in mouse infection model ( Ma et al., 2020 ; Ma et al., 2021 ). The curve of blood bacterial loads in mice infected by strain PU-1 showed the maximum value (more than 10 8 CFU/mL) at 12 h post-infection ( Figure 1A ), which was remarkably higher than the infection groups of virulent ExPEC strain DCE7 from phylogenetic group D ( Zhu et al., 2017 ), and strain DCE1 from group A.…”

“…Bacterial strains and plasmids used in this study were listed in Table S1 . PU-1 is an O2:K1 ExPEC strain (isolated from the blood of a piglet) causing acute sepsis in mouse infection model ( Ma et al., 2020 ; Ma et al., 2021 ). All strains were grown on Luria-Bertani (LB) broth medium at 37°C with 180 rpm, supplemented with corresponding antibiotics, or isopropyl–D-thiogalactopyranoside (IPTG) when necessary.…”

Comparative Metabolic Characterization of Extraintestinal Pathogenic Escherichia coli Blood Isolates from Saudi Arabia

“…However, very little is known about the metabolic factors used by ExPEC to trigger their pathogenesis in the bloodstream. In this regard, a recent Chinese analysis, of the mechanisms of porcine ExPEC blood colonization, has identified the upregulation of many genes included in carbon central metabolism, which might play the main role in porcine ExPEC fitness in bloodstream [ 42 ]. It is our opinion that the significant association between ST131 and rhamnose shown here merits extensive study in the future to look for the role of this relationship in aiding its survival in the bloodstream.…”