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Porin A and α/β-hydrolase are necessary and sufficient for hemolysis induced by Bartonella bacilliformis

Alexander A Dichter1, Florian Winklmeier1, Diana Munteh1

  • 1Institute for Medical Microbiology and Infection Control, University Hospital, Goethe University, Frankfurt am Main, Germany.

Nature Communications
|November 28, 2025
PubMed

Insights

Two Bartonella bacilliformis proteins, porin A and α/β-hydrolase, are essential for causing hemolytic anemia in Carrion's disease. Understanding these virulence factors may lead to new anti-virulence therapies.

Area of Science:

  • Microbiology
  • Infectious Diseases
  • Molecular Biology

Background:

  • Carrion's disease, endemic to the Andes, is a fatal hemolytic anemia caused by Bartonella bacilliformis.
  • Bartonella bacilliformis is a challenging pathogen for genetic studies due to its slow growth and fastidious nature.

Purpose of the Study:

  • To identify the specific factors of Bartonella bacilliformis responsible for inducing hemolysis.
  • To elucidate the molecular mechanisms underlying the hemolytic activity of B. bacilliformis.

Main Methods:

  • Screening of a Tn5 transposon mutant library to identify hemolytic genes.
  • Markerless deletion mutagenesis to generate porin A and α/β-hydrolase deletion mutants.
  • In silico analysis, site-directed mutagenesis, and inhibitor screening to characterize protein function.

Main Results:

  • Porin A and α/β-hydrolase were identified as necessary and sufficient for B. bacilliformis-induced hemolysis.
  • The catalytic triad of α/β-hydrolase (Ser205, Asp267, His310) is crucial for its hemolytic activity.
  • Compound 48/80 was found to be a potent inhibitor of hemolysis in the micromolar range.

Conclusions:

  • Porin A and α/β-hydrolase are key virulence factors in Bartonella bacilliformis.
  • Targeting these factors or their activity could lead to novel anti-virulence strategies against Carrion's disease.
  • These findings are particularly relevant given the rising antibiotic resistance in B. bacilliformis.

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