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In Vivo Biofilm Formation of Pathogenic Leptospira spp. in the Vitreous Humor of Horses with Recurrent Uveitis.
Abstract: Equine recurrent uveitis (ERU) causes painful inflammatory attacks and oftentimes blindness in the affected eyes. The disease is considered a late sequela of systemic leptospirosis. The most effective therapy is the surgical removal of the vitreous (vitrectomy), which is not only therapeutic, but provides vitreous material that can be assessed diagnostically. For example, the lipL32 gene, culturable Leptospira spp., and anti-Leptospira antibodies have all been detected in vitreous samples obtained from eyes with chronic ERU. Despite this clear evidence of leptospiral involvement, the systemic administration of antibiotics in infected horses is ineffective at resolving ERU. This syndrome of chronic recurrent inflammation, which is unresponsive to antibiotic therapy, combined with apparent bacteria evading the immune response, is consistent with a biofilm-associated infection. The purpose of this study, therefore, was to detect the in vivo biofilm formation of Leptospira spp. in vitreous samples collected during vitrectomy and examined using a Warthin-Starry silver stain and immunohistochemistry. All known steps of biofilm formation were visualized in these samples, including individual Leptospira spp., leptospiral microcolonies and dense roundish accumulations of Leptospira spp. In many instances spirochetes were surrounded by an extracellular substance. Taken together, data from the present study show that ERU is a biofilm-associated intraocular leptospiral infection, which best explains the typical clinical course.
Publication Date: 2021-09-09 PubMed ID: 34576809PubMed Central: PMC8464839DOI: 10.3390/microorganisms9091915Google Scholar: Lookup The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
Summary
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The research article discusses how bacteria known as Pathogenic Leptospira are able to form biofilms in the eye fluids of horses with recurrent inflammation, a condition known as Equine Recurrent Uveitis (ERU), leading to blindness. Despite the bacteria’s presence, traditional antibiotic treatment appears ineffective, suggesting a biofilm-associated infection.
Background and Purpose
- The study aims to shed light on Equine Recurrent Uveitis (ERU), a disease in horses that results in painful inflammation and often blindness. This condition is believed to be a terminal event in systemic leptospirosis, a bacterial infection.
- Typically, a surgical procedure called vitrectomy, which involves the removal of the vitreous humor from the eye, offers the most effective treatment for ERU. The extracted vitreous humor can be assessed to help in diagnosis.
- The key goal of the study is the detection and investigation of in vivo biofilm formation by Leptospira spp in vitreous samples obtained from vitrectomy.
Methodology
- Researchers used a Warthin-Starry silver stain and immunohistochemical techniques to examine the vitreous samples collected during the vitrectomy procedure.
Main Findings
- The study found that traditional antibiotic treatment appears largely ineffective at curing ERU, even though there is a clear presence of leptospiral bacteria. This could indicate a biofilm-associated infection, a condition in which bacteria form a protective layer that helps them evade immune responses and resist antibiotics.
- All known stages of biofilm formation, including individual bacteria, bacterial microcolonies, and dense round accumulations of bacteria, were observed in the vitreous samples. In many cases, these spirochetes were found surrounded by an extracellular substance.
Conclusion
- The study concludes that ERU is an intraocular infection associated with biofilm formation by leptospiral bacteria. This observation could explain why the condition follows a typical clinical course and remains resistant to standard antibiotic therapy.
Cite This Article
APA
Ackermann K, Kenngott R, Settles M, Gerhards H, Maierl J, Wollanke B.
(2021).
In Vivo Biofilm Formation of Pathogenic Leptospira spp. in the Vitreous Humor of Horses with Recurrent Uveitis.
Microorganisms, 9(9).
https://doi.org/10.3390/microorganisms9091915 Publication
Researcher Affiliations
- Equine Clinic, Clinical Department, Ludwig-Maximilians-University, 80539 Munich, Germany.
- Institute for Anatomy, Histology and Embryology, Department of Veterinary Science, Ludwig-Maximilians-University, 80539 Munich, Germany.
- Institute for Anatomy, Histology and Embryology, Department of Veterinary Science, Ludwig-Maximilians-University, 80539 Munich, Germany.
- Equine Clinic, Clinical Department, Ludwig-Maximilians-University, 80539 Munich, Germany.
- Institute for Anatomy, Histology and Embryology, Department of Veterinary Science, Ludwig-Maximilians-University, 80539 Munich, Germany.
- Equine Clinic, Clinical Department, Ludwig-Maximilians-University, 80539 Munich, Germany.
Conflict of Interest Statement
The authors declare no conflict of interest.
References
This article includes 99 references
Citations
This article has been cited 12 times.- Kirmse L, Thieme K, Doherr MG, Eule JC. Evaluation of Laboratory Techniques for the Diagnosis of Leptospira-Associated Equine Recurrent Uveitis (ERU) With Focus on the Goldmann-Witmer Coefficient. Vet Ophthalmol 2026 Jan;29(1):e70132.
- Di Azevedo MIN, Kremer F, Ezepha C, Greco JPG, da Silva ICV, Bourhy P, Lilenbaum W. Comparative genomics of Leptospira santarosai reveals genomic adaptations in bovine genital strains. Front Microbiol 2024;15:1517151.
- Dias CS, Pinna MH. Leptospira biofilms: implications for survival, transmission, and disease management. Appl Environ Microbiol 2025 Feb 19;91(2):e0191424.
- Sonam A, Hameed A, Rekha PD, Stothard P, Tellis RC, Arun AB. Ketone body oxidation and susceptibility to ethyl acetoacetate in a novel hemolytic multidrug-resistant strain Leptospira interrogans KeTo originated from sewage water. Sci Rep 2024 Oct 24;14(1):25198.
- Davignon G, Pietrosemoli N, Benaroudj N, Soupé-Gilbert ME, Cagliero J, Turc É, Picardeau M, Guentas L, Goarant C, Thibeaux R. Leptospira interrogans biofilm transcriptome highlights adaption to starvation and general stress while maintaining virulence. NPJ Biofilms Microbiomes 2024 Sep 30;10(1):95.
- Ghosh Moulic A, Deshmukh P, Gaurkar SS. A Comprehensive Review on Biofilms in Otorhinolaryngology: Understanding the Pathogenesis, Diagnosis, and Treatment Strategies. Cureus 2024 Apr;16(4):e57634.
- Nesse LL, Osland AM, Vestby LK. The Role of Biofilms in the Pathogenesis of Animal Bacterial Infections. Microorganisms 2023 Feb 28;11(3).
- Geiger T, Gerhards H, Bjelica B, Mackenthun E, Wollanke B. Analysis of 1840 Equine Intraocular Fluid Samples for the Presence of Anti-Leptospira Antibodies and Leptospiral DNA and the Correlation to Ophthalmologic Findings in Terms of Equine Recurrent Uveitis (ERU)-A Retrospective Study. Vet Sci 2022 Aug 21;9(8).
- Bonhomme D, Werts C. Host and Species-Specificities of Pattern Recognition Receptors Upon Infection With Leptospira interrogans. Front Cell Infect Microbiol 2022;12:932137.
- Fingerhut L, Yücel L, Strutzberg-Minder K, von Köckritz-Blickwede M, Ohnesorge B, de Buhr N. Ex Vivo and In Vitro Analysis Identify a Detrimental Impact of Neutrophil Extracellular Traps on Eye Structures in Equine Recurrent Uveitis. Front Immunol 2022;13:830871.
- Wollanke B, Gerhards H, Ackermann K. Infectious Uveitis in Horses and New Insights in Its Leptospiral Biofilm-Related Pathogenesis. Microorganisms 2022 Feb 7;10(2).
- Geiger T, Gerhards H, Wollanke B. Detection of Anti-LipL32 Antibodies in Serum Samples from Horses with Chronic Intraocular Infection with Leptospira spp. Pathogens 2021 Oct 14;10(10).
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