Interplay between bladder microbiota and urinary antimicrobial peptides: mechanisms for human urinary tract infection risk and symptom severity

PLoS One. 2014 Dec 8;9(12):e114185. doi: 10.1371/journal.pone.0114185. eCollection 2014.

Abstract

Resident bacterial communities (microbiota) and host antimicrobial peptides (AMPs) are both essential components of normal host innate immune responses that limit infection and pathogen induced inflammation. However, their interdependence has not been investigated in the context of urinary tract infection (UTI) susceptibility. Here, we explored the interrelationship between the urinary microbiota and host AMP responses as mechanisms for UTI risk. Using prospectively collected day of surgery (DOS) urine specimens from female pelvic floor surgery participants, we report that the relative abundance and/or frequency of specific urinary microbiota distinguished between participants who did or did not develop a post-operative UTI. Furthermore, UTI risk significantly correlated with both specific urinary microbiota and β-defensin AMP levels. Finally, urinary AMP hydrophobicity and protease activity were greater in participants who developed UTI, and correlated positively with both UTI risk and pelvic floor symptoms. These data demonstrate an interdependency between the urinary microbiota, AMP responses and symptoms, and identify a potential mechanism for UTI risk. Assessment of bacterial microbiota and host innate immune AMP responses in parallel may identify increased risk of UTI in certain populations.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Monophosphate / chemistry
  • Adenosine Monophosphate / urine
  • Anti-Infective Agents / pharmacology
  • Antimicrobial Cationic Peptides / urine*
  • Bacteria / classification
  • Bacteria / drug effects
  • Bacteria / genetics
  • Biodiversity
  • Cohort Studies
  • Enzyme Activation
  • Female
  • Humans
  • Hydrophobic and Hydrophilic Interactions
  • Microbial Sensitivity Tests
  • Microbiota*
  • Peptide Hydrolases / urine
  • Phylogeny
  • Risk Factors
  • Severity of Illness Index
  • Urinary Bladder / microbiology*
  • Urinary Tract Infections / diagnosis
  • Urinary Tract Infections / microbiology*
  • Urinary Tract Infections / urine*
  • beta-Defensins / urine

Substances

  • Anti-Infective Agents
  • Antimicrobial Cationic Peptides
  • DEFB1 protein, human
  • beta-Defensins
  • Adenosine Monophosphate
  • Peptide Hydrolases

Grants and funding

This study was funded by the Loyola University Chicago Stritch School of Medicine Research Funding Committee and the Marion and Ralph C. Falk Medical Research Trust for KAR, AJW and LB. This study was also funded by the Indiana University Foundation for DEN.