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DNA probes for Mycoplasma gallisepticum and Mycoplasma synoviae: application in experimentally infected chickens
H C Hyman1, S Levisohn, D Yogev
1Department of Membrane and Ultrastructure Research, Hadassah Medical School, Hebrew University, Jerusalem, Israel.
Abstract:
DNA probes specific for Mycoplasma gallisepticum and M. synoviae were selected from genomic libraries prepared in the pUC13 vector. The probes hybridized with the DNA of a wide spectrum of strains within each homologous species, but did not react with the heterologous species or with DNA from any other avian mycoplasma or bacteria tested. Experimental infection and contact exposure of chickens to M. gallisepticum served as models to test the effectiveness of the DNA probe in diagnosis as compared with serological and culture detection methods carried out in parallel. A correlation was generally found between the level of M. gallisepticum in tracheal swabs and the effectiveness of the probe, although a predictably reactive level of mycoplasmas was not always detected. Treatment of clinical specimens with acetylcysteine to disrupt mucus improved the detection rate. Dot-blot hybridization with probe pMG4 enabled positive identification of M. gallisepticum at an early stage of infection, prior to the development of a serological response in the infected chicken. Results are obtainable within 4 days of sampling, much more rapidly than culture, and also in clinical specimens from which mycoplasma isolation is impossible, such as carcasses. The results indicate that the use of DNA probes for the early and rapid detection of M. gallisepticum infection is feasible; a development which can replace laborious culture techniques and less effective serological methods, and thus reduce the time required for diagnosis.
Insights
DNA probes offer rapid and early detection of Mycoplasma gallisepticum (MG) infections in chickens. This molecular diagnostic tool surpasses traditional culture and serological methods, improving disease management.
Area of Science:
- Molecular Biology
- Avian Pathology
- Veterinary Diagnostics
Background:
- Mycoplasma gallisepticum (MG) and Mycoplasma synoviae (MS) are significant avian pathogens.
- Current diagnostic methods like culture and serology have limitations in speed and sensitivity.
Purpose of the Study:
- To develop and evaluate DNA probes for the specific and rapid detection of Mycoplasma gallisepticum.
- To compare the diagnostic efficacy of DNA probes with conventional methods.
Main Methods:
- Genomic libraries in pUC13 vector were used to select specific DNA probes.
- Dot-blot hybridization was performed on clinical samples from experimentally infected chickens.
- Acetylcysteine treatment was used to improve sample processing.
- Results were compared with parallel serological and culture detection.
Main Results:
- Developed probes showed high specificity for homologous species (MG and MS) without cross-reactivity.
- Dot-blot hybridization with probe pMG4 enabled early detection of MG infection, preceding serological response.
- Detection rates correlated with pathogen levels in tracheal swabs, improved by mucus disruption.
- Results were obtained within 4 days, significantly faster than culture.
- Enabled detection in challenging samples like carcasses.
Conclusions:
- DNA probes provide a feasible method for early and rapid diagnosis of Mycoplasma gallisepticum infections.
- This molecular approach can replace laborious culture techniques and less sensitive serological methods.
- Accelerated diagnosis reduces overall disease management time.