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ARS Home » Southeast Area » Mississippi State, Mississippi » Poultry Research » Research » Publications at this Location » Publication #310744
Title: Fluorescent microspheres as a positive indicator in an inratracheal infection model

Author
item Leigh, Spencer
item Branton, Scott
item Evans, Jeffrey - Jeff
item Collier, Stephanie

Submitted to: Journal of Microbiological Methods
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/5/2020
Publication Date: 3/17/2020
Citation: Leigh, S.A., Branton, S.L., Evans, J.D., Collier, S.D. 2020. Fluorescent microspheres as a positive indicator in an inratracheal infection model. Journal of Microbiological Methods. 172:105886. https://doi.org/10.1016/j.mimet.2020.105886.
DOI: https://doi.org/10.1016/j.mimet.2020.105886

Interpretive Summary: Mycoplasma gallisepticum causes chronic respiratory disease in chickens and infectious sinusitis in turkeys. In order to facilitate study of the disease process, a simple, rapid, consistent infection model is needed that incorporates a positive marker for M. gallisepticum infection. Previous work had demonstrated that simple intratracheal infections resulted in consistent disease, and that vaccination with F-strain M. gallisepticum prevented disease symptoms. Fluorescent microspheres were incorporated into this model as part of the infection process. These microspheres lodge in the chicken lung tissue when the chicken has been properly infected. The beads are visualized during necropsy by means of a 365 nm light. Use of the updated model system demonstrated that F-strain M. gallisepticum provided almost total protection, while the ts-11 and 6/85 vaccines provided moderate to minimal protection respectively. Use of this model system will enhance research into the protective nature of current M. gallisepticum vaccines and the development of improved vaccines, leading to a decrease in production costs for poultry producers.

Technical Abstract: This work describes the improvement of a model system of intratracheal infection using fluorescent microspheres as a positive indicator of infection. It was shown that fluorescent microspheres remained detectable in the chicken lung tissue for at least 7 days following infection. The microspheres used are detectable using a black light, allowing for visualization during necropsy. Using the updated model system, three live Mycoplasma gallisepticum vaccines were tested both for their ability to elicit a humoral immune response following vaccination, and also for their ability to protect from airsac lesion pathology at two different time points following vaccination. It was shown that the F-strain vaccine achieved near complete protection at six weeks post vaccination. Neither the ts-11 nor the 6/85 vaccines provided sufficient protection against airsac lesion pathology at six weeks post vaccination. The presence of the fluorescent microspheres provided a positive method of identifying the properly infected chickens and removed doubts about samples with results significantly different than expected.