RT-qPCR for the diagnosis of dermatophilosis in horses.
Abstract: Dermatophilus congolensis causes a crusting dermatitis that affects horses. Diagnosis requires the identification of the organism with cytological evaluation of crust samples. This method can lack sensitivity in chronic cases. Objective: To develop a probe-based real time quantitative polymerase chain reaction (RT-qPCR) test to assist with the diagnosis of dermatophilosis in horses. Methods: Twenty six privately owned horses and seven horses from a research colony were used. Methods: Crust samples, collected from 14 horses with suspected dermatophilosis and 12 horses with crusting skin disease not characteristic of dermatophilosis, were evaluated by cytological evaluation and RT-qPCR; the latter was also performed on hair samples collected from seven healthy horses. Results: Cytological evaluation revealed organisms consistent with Dermatophilus congolensis from nine horses with suspected dermatophilosis, with only a few organisms seen from five samples. Cytological evaluation of all other crusts was negative for Dermatophilus. Other bacterial organisms were detected on cytological evaluation from 15 samples. RT-qPCR for Dermatophilus was positive from 11 crusts, whereas all other samples were negative. Two samples were cytologically negative but RT-qPCR positive for Dermatophilus. No samples were cytologically positive but RT-qPCR negative for Dermatophilus. Conclusions: Results of this study show that RT-qPCR may be a more sensitive and easier method than cytological evaluation for the diagnosis of dermatophilosis in horses.
© 2016 ESVD and ACVD.
Publication Date: 2016-08-03 PubMed ID: 27485381DOI: 10.1111/vde.12368Google Scholar: Lookup
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- Journal Article
Summary
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The research is about developing a more sensitive method for diagnosing dermatophilosis, a skin disease in horses, using real-time quantitative polymerase chain reaction (RT-qPCR) testing. The results of the study suggest that RT-qPCR may be more efficient and accurate than the traditional cytological evaluation method.
Objective and Methodology
- The goal of the study was to devise a more sensitive and easier method for diagnosing dermatophilosis, a common skin condition in horses caused by the bacteria Dermatophilus congolensis.
- Traditionally, diagnosis is performed through a cytological evaluation of the skin crust samples, a method that can lack sensitivity, particularly in chronic cases.
- The researchers hypothesized that real-time quantitative polymerase chain reaction (RT-qPCR), a method used to amplify and simultaneously monitor the amplification of a targeted DNA molecule, could prove to be a more effective testing procedure.
- The study involved twenty-six privately-owned horses, along with seven horses from a research colony. Crust and hair samples were collected from horses with suspected dermatophilosis and horses with other types of crusting skin disease for comparison.
Results
- The traditional cytological evaluation method detected Dermatophilus bacteria in nine out of fourteen horses with suspected dermatophilosis. However, in five of those samples, only a few organisms were observed, indicating a possible lack of sensitivity.
- On the contrary, RT-qPCR testing gave positive results for Dermatophilus in eleven out of the fourteen suspected dermatophilosis samples, suggesting higher sensitivity than cytological evaluation.
- More importantly, two samples that tested negative with cytological evaluation tested positive with RT-qPCR, reinforcing the notion that RT-qPCR might be the superior diagnostic method.
- None of the samples produced conflicting results where they were cytologically positive but RT-qPCR negative.
Conclusion
- The outcome of this study suggested that RT-qPCR has the potential to be a more sensitive and easier method for diagnosing dermatophilosis in horses than the current cytological evaluation practice.
- This could lead to quicker and more accurate diagnoses, enabling more effective treatment plans for the horses affected by this condition.
Cite This Article
APA
Frank LA, Kania SA, Weyant E.
(2016).
RT-qPCR for the diagnosis of dermatophilosis in horses.
Vet Dermatol, 27(5), 431-e112.
https://doi.org/10.1111/vde.12368 Publication
Researcher Affiliations
- Department of Small Animal Clinical Sciences, University of Tennessee, 2407 River Drive, Knoxville, TN, 37996, USA. lfrank@utk.edu.
- Department of Biomedical and Diagnostic Sciences, University of Tennessee, 2407 River Drive, Knoxville, TN, 37996, USA.
- Department of Biomedical and Diagnostic Sciences, University of Tennessee, 2407 River Drive, Knoxville, TN, 37996, USA.
MeSH Terms
- Actinobacteria / isolation & purification
- Animals
- Gram-Positive Bacterial Infections / diagnosis
- Gram-Positive Bacterial Infections / microbiology
- Gram-Positive Bacterial Infections / veterinary
- Horse Diseases / microbiology
- Horses
- Reverse Transcriptase Polymerase Chain Reaction / methods
- Reverse Transcriptase Polymerase Chain Reaction / veterinary
- Skin Diseases, Bacterial / microbiology
- Skin Diseases, Bacterial / pathology
- Skin Diseases, Bacterial / veterinary
Citations
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