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Histamine Promotes Pseudomonas aeruginosa Biofilm Formation and Renders P. aeruginosa Biofilms More Resistant to
1Welcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, UK.
Introduction:
Pseudomonas aeruginosa biofilms contribute to the persistent presence of this bacterium in the cystic fibrosis airways. P. aeruginosa produces histamine in vitro and expresses histamine receptors. We investigated whether histamine regulated P. aeruginosa biofilm formation in vitro and contributed to bacterial virulence in Galleria mellonella.
Methods:
P. aeruginosa biofilms were measured by staining bacteria adhered on polystyrene with crystal violet. Histamine concentrations were measured by ELISA. G. mellonella survival upon inoculation with P. aeruginosa was measured in the absence or presence of histamine.
Results:
The concentration of histamine in the BHI broth was 140 ng/mL (1.3 μ
Conclusion:
Histamine produced during periods of infection may augment P. aeruginosa virulence by promoting the biofilm mode of life of this bacterium.
Insights
Histamine, a molecule produced during infections, significantly enhances Pseudomonas aeruginosa biofilm formation and increases bacterial virulence. This suggests histamine plays a key role in persistent P. aeruginosa infections, particularly in cystic fibrosis.
Area of Science:
- Microbiology
- Infectious Diseases
- Biofilm Research
Background:
- Pseudomonas aeruginosa biofilms are a major factor in persistent airway infections, especially in cystic fibrosis.
- P. aeruginosa synthesizes histamine and possesses histamine receptors, indicating a potential role for histamine in its biology.
Purpose of the Study:
- To investigate the role of histamine in regulating P. aeruginosa biofilm formation in vitro.
- To determine if histamine contributes to P. aeruginosa virulence in a Galleria mellonella infection model.
Main Methods:
- Biofilm quantification using crystal violet staining.
- Histamine concentration measurement via ELISA.
- Galleria mellonella survival assays following P. aeruginosa inoculation with and without histamine.
Main Results:
- Diamine oxidase (DAO), an enzyme degrading histamine, reduced P. aeruginosa biofilms by twofold.
- Histamine addition augmented P. aeruginosa biofilm formation in a dose-dependent manner.
- Histamine exposure reduced the efficacy of antibiotics gentamicin and azithromycin against established biofilms.
- Histamine administration decreased Galleria mellonella survival rates when infected with P. aeruginosa.
Conclusions:
- Histamine promotes P. aeruginosa biofilm formation, contributing to its virulence.
- Histamine may enhance P. aeruginosa persistence in host infections by promoting biofilm development.
