Enhanced biofilm and extracellular matrix production by chronic carriage versus acute isolates of Salmonella Typhi

PLoS Pathog. 2021 Jan 19;17(1):e1009209. doi: 10.1371/journal.ppat.1009209. eCollection 2021 Jan.

Abstract

Salmonella Typhi is the primary causative agent of typhoid fever; an acute systemic infection that leads to chronic carriage in 3-5% of individuals. Chronic carriers are asymptomatic, difficult to treat and serve as reservoirs for typhoid outbreaks. Understanding the factors that contribute to chronic carriage is key to development of novel therapies to effectively resolve typhoid fever. Herein, although we observed no distinct clustering of chronic carriage isolates via phylogenetic analysis, we demonstrated that chronic isolates were phenotypically distinct from acute infection isolates. Chronic carriage isolates formed significantly thicker biofilms with greater biomass that correlated with significantly higher relative levels of extracellular DNA (eDNA) and DNABII proteins than biofilms formed by acute infection isolates. Importantly, extracellular DNABII proteins include integration host factor (IHF) and histone-like protein (HU) that are critical to the structural integrity of bacterial biofilms. In this study, we demonstrated that the biofilm formed by a chronic carriage isolate in vitro, was susceptible to disruption by a specific antibody against DNABII proteins, a successful first step in the development of a therapeutic to resolve chronic carriage.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies, Monoclonal / pharmacology
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Biofilms / drug effects
  • Biofilms / growth & development*
  • DnaB Helicases / antagonists & inhibitors
  • DnaB Helicases / genetics
  • DnaB Helicases / metabolism*
  • Extracellular Matrix / metabolism*
  • Humans
  • Integration Host Factors / genetics
  • Integration Host Factors / metabolism*
  • Salmonella typhi / classification
  • Salmonella typhi / genetics
  • Salmonella typhi / pathogenicity*
  • Typhoid Fever / drug therapy
  • Typhoid Fever / immunology
  • Typhoid Fever / microbiology*

Substances

  • Antibodies, Monoclonal
  • Bacterial Proteins
  • Integration Host Factors
  • DnaB Helicases