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Autofluorescence in samples obtained from chronic biofilm infections--"all that glitters is not gold"
Steffen Eickhardt1, Kasper N Kragh2, Stine Schrøder3
1Costerton Biofilm Center, Department of International Health, Immunology & Microbiology, The faculty of Health and Medical Sciences, The University of Copenhagen, Denmark The Department of Clinical Microbiology, Rigshospitalet, Denmark sreis@sund.ku.dk.
Abstract:
When looking at tissue sections of ex vivo samples, autofluorescence can be a major cause of artifacts and misinterpretations. We here reiterate evidence that autofluorescing granules, often hemosiderin but also ceroid or mucinogen granules, are severe obstacles when imaging and diagnosing biofilm infections through fluorescent imaging techniques. We used confocal laser scanning microscopy with spectral analysis for autofluorescence detection as well as standard histological stains in order to identify the culprit and show that these granules might very well be mistaken for bacterial biofilms. Furthermore, we hypothesize that the increased amount of autofluorescing granules may be a consequence of prolonged inflammation as a consequence of chronic biofilm infections.
Insights
Autofluorescent granules in tissue samples can mimic bacterial biofilms, leading to misdiagnosis in fluorescence imaging. Increased granules may indicate chronic inflammation from biofilm infections.
Area of Science:
- Microscopy
- Histopathology
- Biomedical Imaging
Background:
- Autofluorescence in ex vivo tissue samples causes artifacts and misinterpretations.
- Autofluorescing granules like hemosiderin, ceroid, and mucinogen can obscure bacterial biofilms.
- Accurate diagnosis of biofilm infections using fluorescence imaging is challenged by these autofluorescent artifacts.
Purpose of the Study:
- To identify the source of autofluorescence that mimics bacterial biofilms in histological samples.
- To investigate the potential link between increased autofluorescing granules and chronic biofilm infections.
Main Methods:
- Confocal laser scanning microscopy with spectral analysis was employed for autofluorescence detection.
- Standard histological stains were utilized to identify the autofluorescing components.
- Ex vivo tissue sections were analyzed to differentiate granules from bacterial biofilms.
Main Results:
- Autofluorescing granules, including hemosiderin, ceroid, and mucinogen, were confirmed as significant obstacles in biofilm imaging.
- These granules can be erroneously identified as bacterial biofilms during fluorescence microscopy.
- A hypothesis was proposed suggesting that chronic inflammation from biofilm infections may increase autofluorescing granule accumulation.
Conclusions:
- Autofluorescence from endogenous granules presents a diagnostic challenge in identifying bacterial biofilms via fluorescence microscopy.
- Distinguishing these granules from actual biofilms is crucial for accurate diagnosis and treatment of chronic infections.
- Further research is warranted to explore the relationship between inflammation and autofluorescent granule accumulation in chronic biofilm diseases.
