Evaluation of a PCR assay on overgrown environmental samples cultured for Mycobacterium avium subsp. paratuberculosis
| Autor: | Juan Carlos Arango-Sabogal, J M Fairbrother, Olivia Labrecque, Julie Paré, Jean-Philippe Roy, Vincent Wellemans, Gilles Fecteau |
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| Rok vydání: | 2016 |
| Předmět: |
0301 basic medicine
DNA Bacterial Bacilli 040301 veterinary sciences 030106 microbiology Paratuberculosis Cattle Diseases Stain Polymerase Chain Reaction law.invention Microbiology 0403 veterinary science 03 medical and health sciences law medicine Animals Incubation Polymerase chain reaction General Veterinary biology 04 agricultural and veterinary sciences medicine.disease biology.organism_classification Fold change Mycobacterium avium subsp. paratuberculosis Dairying Cattle Female Mycobacterium |
| Zdroj: | Journal of veterinary diagnostic investigation : official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc. 28(6) |
| ISSN: | 1943-4936 |
| Popis: | Culture of Mycobacterium avium subsp. paratuberculosis (MAP) is the definitive antemortem test method for paratuberculosis. Microbial overgrowth is a challenge for MAP culture, as it complicates, delays, and increases the cost of the process. Additionally, herd status determination is impeded when noninterpretable (NI) results are obtained. The performance of PCR is comparable to fecal culture, thus it may be a complementary detection tool to classify NI samples. Our study aimed to determine if MAP DNA can be identified by PCR performed on NI environmental samples and to evaluate the performance of PCR before and after the culture of these samples in liquid media. A total of 154 environmental samples (62 NI, 62 negative, and 30 positive) were analyzed by PCR before being incubated in an automated system. Growth was confirmed by acid-fast bacilli stain and then the same PCR method was again applied on incubated samples, regardless of culture and stain results. Change in MAP DNA after incubation was assessed by converting the PCR quantification cycle (Cq) values into fold change using the 2−ΔCqmethod (ΔCq = Cq after culture − Cq before culture). A total of 1.6% (standard error [SE] = 1.6) of the NI environmental samples had detectable MAP DNA. The PCR had a significantly better performance when applied after culture than before culture ( p = 0.004). After culture, a 66-fold change (SE = 17.1) in MAP DNA was observed on average. Performing a PCR on NI samples improves MAP culturing. The PCR method used in our study is a reliable and consistent method to classify NI environmental samples. |
| Databáze: | OpenAIRE |
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