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In vitro Biofilm Formation in an 8-well Chamber Slide
Published on: January 20, 2011
Haemophilus parainfluenzae Strain ATCC 33392 Forms Biofilms In Vitro and during Experimental Otitis Media Infections
Bing Pang1, W Edward Swords2,3
1Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA.
Abstract:
Haemophilus parainfluenzae is a nutritionally fastidious, Gram-negative bacterium with an oropharyngeal/nasopharyngeal carriage niche that is associated with a range of opportunistic infections, including infectious endocarditis and otitis media (OM). These infections are often chronic/recurrent in nature and typically involve bacterial persistence within biofilm communities that are highly resistant to host clearance. This study addresses the primary hypothesis that H. parainfluenzae forms biofilm communities that are important determinants of persistence in vivo The results from in vitro biofilm studies confirmed that H. parainfluenzae formed biofilm communities within which the polymeric matrix was mainly composed of extracellular DNA and proteins. Using a chinchilla OM infection model, we demonstrated that H. parainfluenzae formed surface-associated biofilm communities containing bacterial and host components that included neutrophil extracellular trap (NET) structures and that the bacteria mainly persisted in these biofilm communities. We also used this model to examine the possible interaction between H. parainfluenzae and its close relative Haemophilus influenzae, which is also commonly carried within the same host environments and can cause OM. The results showed that coinfection with H. influenzae promoted clearance of H. parainfluenzae from biofilm communities during OM infection. The underlying mechanisms for bacterial persistence and biofilm formation by H. parainfluenzae and knowledge about the survival defects of H. parainfluenzae during coinfection with H. influenzae are topics for future work.
Insights
Haemophilus parainfluenzae forms persistent biofilms in otitis media, crucial for survival. Coinfection with Haemophilus influenzae promotes H. parainfluenzae clearance from these biofilms.
Area of Science:
- Microbiology
- Bacterial Pathogenesis
- Host-Pathogen Interactions
Background:
- Haemophilus parainfluenzae is a Gram-negative bacterium causing opportunistic infections like otitis media (OM).
- Bacterial persistence in chronic/recurrent infections is often linked to biofilm formation, which resists host clearance.
- Haemophilus parainfluenzae's role in persistent infections and biofilm dynamics requires further investigation.
Purpose of the Study:
- To test the hypothesis that Haemophilus parainfluenzae forms biofilms that are key to its persistence in vivo.
- To investigate the composition of H. parainfluenzae biofilms.
- To examine the impact of Haemophilus influenzae coinfection on H. parainfluenzae persistence within biofilms during OM.
Main Methods:
- In vitro biofilm formation assays.
- Chinchilla model of otitis media infection.
- Analysis of biofilm composition, including bacterial and host factors.
- Comparative analysis of H. parainfluenzae monoinfection and coinfection with H. influenzae.
Main Results:
- In vitro studies confirmed H. parainfluenzae forms biofilms with extracellular DNA and proteins.
- In vivo, H. parainfluenzae formed surface-associated biofilms containing bacterial and host components, including neutrophil extracellular traps (NETs).
- Coinfection with H. influenzae led to the clearance of H. parainfluenzae from biofilms during OM.
Conclusions:
- Haemophilus parainfluenzae forms biofilms that are critical for its persistence in otitis media.
- Neutrophil extracellular traps are components of H. parainfluenzae biofilms in vivo.
- Haemophilus influenzae coinfection negatively impacts H. parainfluenzae persistence by promoting its clearance from biofilms.
