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Detection of Mycoplasma pulmonis in experimentally infected laboratory rats by 16S rRNA amplification
F J van Kuppeveld1, W J Melchers, H F Willemse
1Department of Medical Microbiology, University of Nijmegen, The Netherlands.
Abstract:
Recently, an rRNA-based polymerase chain reaction (PCR) has been developed for the detection of murine mycoplasmas at both the genus and species level (F. J. M. van Kuppeveld, J. T. M. van der Logt, A. F. Angulo, M. J. van Zoest, W. G. V. Quint, H. G. Niesters, J. M. D. Galama, and W. J. G. Melchers, Appl. Environ. Microbiol. 58:2606-2615, 1992). In this study, the diagnostic value of this PCR assay for the detection of Mycoplasma pulmonis in infected rats was studied. For this purpose, 25 Wistar rats were infected intranasally with M. pulmonis strain M72-138 and investigated for the presence of this pathogen by both in vitro isolation and PCR. Five rats were monitored longitudinally by screening of throat swabs at several time points for up to 248 days postinfection. The remaining 20 rats were killed between 3 and 87 days postinfection, and organism recovery from both throat and urogenital tract specimens was attempted. M. pulmonis could be detected in the throat for up to 248 days postinfection but not in the urogenital tract, either by culture or by PCR. PCR proved to be the optimal method for testing throat samples. All samples in which M. pulmonis was detected by culture were also positive by PCR. By PCR, M. pulmonis was also detected in 3.7% of the samples which were culture negative and in 9.9% of the samples from which cultures were overgrown with bacteria. The results of this study demonstrate the suitability of PCR for the detection of mycoplasmal infection in rodents.
Insights
This study evaluated a polymerase chain reaction (PCR) assay for detecting Mycoplasma pulmonis in rats. PCR proved superior to culture for identifying this pathogen in throat swabs, even in challenging samples.
Area of Science:
- Veterinary Microbiology
- Molecular Diagnostics
- Rodent Health
Background:
- Murine mycoplasmas are significant pathogens in laboratory rodents.
- Accurate and sensitive detection methods are crucial for animal health and research integrity.
- Previous rRNA-based polymerase chain reaction (PCR) methods existed for murine mycoplasmas.
Purpose of the Study:
- To assess the diagnostic performance of an rRNA-based PCR assay for detecting Mycoplasma pulmonis in experimentally infected rats.
- To compare PCR with traditional in vitro isolation for Mycoplasma pulmonis detection.
- To determine the duration and sites of Mycoplasma pulmonis shedding in infected rats.
Main Methods:
- Wistar rats were intranasally inoculated with Mycoplasma pulmonis.
- Throat and urogenital tract specimens were collected longitudinally and at necropsy.
- Samples were analyzed using both in vitro culture and rRNA-based PCR.
- PCR sensitivity was evaluated against culture results, including culture-negative and overgrown samples.
Main Results:
- Mycoplasma pulmonis was detectable in rat throat swabs for up to 248 days post-infection via PCR.
- PCR identified Mycoplasma pulmonis in samples negative by culture (3.7%) and those overgrown with bacteria (9.9%).
- The pathogen was not detected in the urogenital tract by either method.
Conclusions:
- The rRNA-based PCR assay is a highly sensitive and optimal method for detecting Mycoplasma pulmonis in rat throat samples.
- PCR offers significant advantages over culture, especially in detecting low-level infections or samples with bacterial contamination.
- This study validates PCR as a suitable diagnostic tool for mycoplasmal infections in rodent research settings.