Evaluation of a real-time quantitative polymerase chain reaction assay for detection and quantitation of virulent Rhodococcus equi.
Abstract: To evaluate a real-time quantitative polymerase chain reaction (QPCR) assay in the detection and quantitation of virulent Rhodococcus equi. Methods: 1 virulent, 2 intermediately virulent, and 2 avirulent strains of R. equi and 16 isolates of bacteria genetically related to R. equi. Methods: The QPCR assay was evaluated for detection and quantitation of the virulence-associated gene (vapA) of R. equi in pure culture and in samples of tracheobronchial fluid, which were inoculated with known numbers of virulent R. equi. Results were compared with those derived via quantitative microbial culture and standard polymerase chain reaction methods. Results: The QPCR assay detected the vapA gene in pure culture of R. equi and in tracheobronchial fluid samples that contained as few as 20 CFUs of virulent R. equi/mL and accurately quantitated virulent R. equi to 10(3) CFUs/mL of fluid. The assay was highly specific for detection of the vapA gene of virulent R. equi and was more sensitive than standard polymerase chain reaction for detection of R. equi in tracheobronchial fluid. Conclusions: The QPCR assay appears to be a rapid and reliable method for detecting and quantitating virulent R. equi. The accuracy of the QPCR assay is comparable to that of quantitative microbial culture. The increased sensitivity of the QPCR method in detection of virulent R. equi should facilitate rapid and accurate diagnosis of R. equi pneumonia in foals.
Publication Date: 2005-06-09 PubMed ID: 15940818DOI: 10.2460/ajvr.2005.66.755Google 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.
- Evaluation Study
- Journal Article
- Research Support
- Non-U.S. Gov't
- Bronchoalveolar Lavage
- Clinical Study
- Diagnosis
- Diagnostic Technique
- Disease Diagnosis
- Equine Health
- Foals
- Infectious Disease
- Laboratory Methods
- Microbiology
- Molecular biology
- Pneumonia
- Polymerase Chain Reaction
- Quantitative Analysis
- Real-Time PCR
- Respiratory Disease
- Rhodococcus equi
- Trachea
- Veterinary Medicine
- Virulence
Summary
This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.
This research tested a real-time quantitative polymerase chain reaction (QPCR) assay for detecting and measuring amounts of a bacteria called virulent Rhodococcus equi. The study found that the QPCR assay is a quick and reliable method that can detect even small amounts of the bacteria and could aid in accurately diagnosing diseases like foal pneumonia.
Objective and Methodology
- The main goal of this research was to assess the effectiveness of a real-time quantitative polymerase chain reaction (QPCR) assay in detecting and quantifying virulent Rhodococcus equi, a bacteria that can cause diseases like pneumonia in young horses.
- The study used one virulent strain, two intermediately virulent strains, and two avirulent strains of R. equi, along with 16 isolates of bacteria genetically related to R. equi.
- The QPCR assay’s task was to identify and measure the amount of virulence-associated gene (vapA) of R. equi in pure culture and in tracheobronchial fluid samples inoculated with this bacteria.
- Its results were then compared with those derived from quantitative microbial culture and standard polymerase chain reaction methods.
Results and Findings
- The QPCR assay could detect the vapA gene in pure culture of R. equi and in tracheobronchial fluid samples containing as few as 20 Colony Forming Units (CFUs) per mL of virulent R. equi.
- In addition, the method was able to accurately quantify the number of virulent R. equi to 103 CFUs/mL of fluid.
- It was highly specific for detecting the vapA gene and showed greater sensitivity than standard polymerase chain reaction in detecting R. equi in tracheobronchial fluid.
Conclusion and Applications
- The QPCR assay proved to be quick and efficient in detecting and quantifying virulent R. equi.
- Its accuracy is on par with that of the traditional quantitative microbial culture method.
- The assay’s enhanced sensitivity over standard detection methods can potentially lead to quicker and more precise diagnosis of diseases caused by R. equi, like foal pneumonia.
Cite This Article
APA
Harrington JR, Golding MC, Martens RJ, Halbert ND, Cohen ND.
(2005).
Evaluation of a real-time quantitative polymerase chain reaction assay for detection and quantitation of virulent Rhodococcus equi.
Am J Vet Res, 66(5), 755-761.
https://doi.org/10.2460/ajvr.2005.66.755 Publication
Researcher Affiliations
- Department of Large Animal Medicine, College of Veterinary Medicine, Texas A&M University, College Station, TX 77843, USA.
MeSH Terms
- Actinomycetales Infections / diagnosis
- Actinomycetales Infections / veterinary
- Animals
- Bronchoalveolar Lavage Fluid / microbiology
- DNA, Bacterial / analysis
- Horse Diseases / diagnosis
- Horse Diseases / microbiology
- Horses
- Polymerase Chain Reaction / methods
- Rhodococcus equi / isolation & purification
- Rhodococcus equi / pathogenicity
- Sensitivity and Specificity
- Virulence
Citations
This article has been cited 6 times.- Sting R, Schwabe I, Kieferle M, Münch M, Rau J. Fatal Infection in an Alpaca (Vicugna pacos) Caused by Pathogenic Rhodococcus equi. Animals (Basel) 2022 May 19;12(10).
- Narváez SÁ, Fernández I, Patel NV, Sánchez S. Novel Quantitative PCR for Rhodococcus equi and Macrolide Resistance Detection in Equine Respiratory Samples. Animals (Basel) 2022 May 3;12(9).
- Madrigal RG, Shaw SD, Witkowski LA, Sisson BE, Blodgett GP, Chaffin MK, Cohen ND. Use of Serial Quantitative PCR of the vapA Gene of Rhodococcus equi in Feces for Early Detection of R. equi Pneumonia in Foals. J Vet Intern Med 2016 Mar-Apr;30(2):664-70.
- Stefańska I, Witkowski L, Rzewuska M, Dzieciątkowski T. Development and evaluation of the internal-controlled real-time PCR assay for Rhodococcus equi detection in various clinical specimens. J Vet Med Sci 2016 May 3;78(4):543-9.
- Shaw SD, Cohen ND, Chaffin MK, Blodgett GP, Syndergaard M, Hurych D. Estimating the Sensitivity and Specificity of Real-Time Quantitative PCR of Fecal Samples for Diagnosis of Rhodococcus equi Pneumonia in Foals. J Vet Intern Med 2015 Nov-Dec;29(6):1712-7.
- Rodríguez-Lázaro D, Lewis DA, Ocampo-Sosa AA, Fogarty U, Makrai L, Navas J, Scortti M, Hernández M, Vázquez-Boland JA. Internally controlled real-time PCR method for quantitative species-specific detection and vapA genotyping of Rhodococcus equi. Appl Environ Microbiol 2006 Jun;72(6):4256-63.
Use Nutrition Calculator
Check if your horse's diet meets their nutrition requirements with our easy-to-use tool Check your horse's diet with our easy-to-use tool
Talk to a Nutritionist
Discuss your horse's feeding plan with our experts over a free phone consultation Discuss your horse's diet over a phone consultation
Submit Diet Evaluation
Get a customized feeding plan for your horse formulated by our equine nutritionists Get a custom feeding plan formulated by our nutritionists
