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Updated: Jul 13, 2026
Swine Model of Biofilm Infection and Invisible Wounds
Published on: June 16, 2023
A sheep model for the study of biofilms in rhinosinusitis
Kien R Ha1, Alkis J Psaltis, Lorwai Tan
1Department of Surgery-Otorhinolaryngology, Head and Neck Surgery, The Queen Elizabeth Hospital, Adelaide, Australia and University of Adelaide, Adelaide, SA, Australia.
Background:
Bacterial biofllms have been shown in chronic diseases such as cystic fibrosis, cholesteatoma, and otitis media with effusion. Recently, their detection on the mucosal tissue of sinusitis patients has implicated them in the pathogenesis of this condition. We present an animal model using sheep experimentally infected with Staphylococcus aureus to study the possible association between biofilm and sinusitis.
Methods:
Twenty-four sheep underwent bilateral endoscopic sinus surgery to identify their frontal ostia. The frontal sinuses were treated in one of the following ways according to preoperative randomization: (1) ostium left patent, (2) ostium left patent and bacteria instilled, (3) ostium occluded, or (4) ostium occluded and bacteria instilled. The frontal mucosa was harvested at day 7 and examined for biofilm presence using confocal scanning laser microscopy (CSLM) as well as scanning electron microscopy (SEM) and transmission electron microscopy (TEM).
Results:
All three modalities showed different rates of biofilm detection. Three-dimensional structures that could be interpreted as biofilms were documented in 86% (n = 36) of the sinuses analyzed using SEM. These structures were seen in all four study groups. The detection rate using the other two modalities was much lower with CSLM, showing biofilms in 48% (n = 20) and TEM in only 29% (n = 12) of the sinuses analyzed. Unlike SEM, these two modalities only detected bacterial biofilms in sinuses randomized to bacterial instillation.
Conclusion:
The demonstration of bacterial biofilms in this animal model of sinusitis further supports the hypotheses that biofilms may play a role in the pathogenesis of this condition. There is an obvious discrepancy in the sensitivity and specificity of biofilm detection using the three modalities mentioned. CSLM appears to be the most objective technique. The inherent flaws, sampling error, and subjectivity involved in SEM and TEM make these less reliable in documenting biofilm existence.
Insights
Bacterial biofilms are implicated in sinusitis. This sheep model demonstrated biofilms in infected sinuses, supporting their role in disease pathogenesis and highlighting discrepancies in detection methods. Confocal scanning laser microscopy (CSLM) is most reliable.
Area of Science:
- Otorhinolaryngology
- Microbiology
- Pathogenesis
Background:
- Bacterial biofilms are linked to chronic diseases like cystic fibrosis and otitis media.
- Recent findings suggest biofilms contribute to sinusitis pathogenesis.
- This study investigates biofilms in a novel sheep model of sinusitis.
Purpose of the Study:
- To establish and utilize a sheep model for studying bacterial biofilms in sinusitis.
- To assess the association between Staphylococcus aureus biofilms and sinusitis development.
- To compare the efficacy of different microscopy techniques in detecting biofilms.
Main Methods:
- Twenty-four sheep underwent endoscopic sinus surgery.
- Frontal sinuses were randomized into four groups: patent ostium, patent ostium with bacterial instillation, occluded ostium, and occluded ostium with bacterial instillation.
- Frontal mucosa was harvested on day 7 and analyzed for biofilms using scanning electron microscopy (SEM), confocal scanning laser microscopy (CSLM), and transmission electron microscopy (TEM).
Main Results:
- SEM detected biofilm-like structures in 86% of sinuses across all groups.
- CSLM detected biofilms in 48% of sinuses, and TEM in 29%, primarily in groups with bacterial instillation.
- Significant discrepancies were observed in biofilm detection rates among the three microscopy techniques.
Conclusions:
- The presence of bacterial biofilms in this sinusitis model supports their role in disease pathogenesis.
- CSLM demonstrated higher objectivity for biofilm detection compared to SEM and TEM.
- SEM and TEM showed limitations due to sampling error and subjectivity, making them less reliable for biofilm documentation.
