Isolation and characterization of a 6/85-like Mycoplasma gallisepticum from commercial laying hens

• Published in: Avian diseases Vol. 47; no. 2; p. 499
• Main Authors: Throne Steinlage, S J, Ferguson, N, Sander, J E, García, M, Subramanian, S, Leiting, V A, Kleven, S H
• Format: Journal Article
• Language: English
• Published: United States 01.04.2003
• Subjects: Air Sacs - microbiology; Air Sacs - pathology; Animals; Antibodies, Bacterial - immunology; Bacterial Vaccines - adverse effects; Bacterial Vaccines - immunology; Chickens - microbiology; Female; Mycoplasma - classification; Mycoplasma - immunology; Mycoplasma - isolation & purification; Mycoplasma - pathogenicity; Sequence Analysis, DNA; Trachea - microbiology; Trachea - pathology
• ISSN: 0005-2086
• DOI: 10.1637/0005-2086(2003)047[0499:IACOAL]2.0.CO;2

Eighty-three-week-old table egg layers with swollen sinuses were presented with a history of increased mortality. Serology revealed positive titers to Mycoplasma gallisepticum (MG). The birds were part of a flock in which some birds had been vaccinated with 6/85 live MG vaccine at 18 wk of age. Tracheal cultures were obtained from both vaccinated and unvaccinated birds within the flock. The cultures were indistinguishable from 6/85 vaccine by both random amplified polymorphic DNA analysis and DNA sequence analysis. Challenge studies were performed to compare the field isolates with 6/85 vaccine and the R strain of MG. The field isolates produced a greater antibody response by serum plate agglutination than did the 6/85 vaccine. The isolates effectively colonized the trachea without increasing the tracheal mucosal thickness; however, they did not extensively colonize the air sacs or cause airsacculitis in the experimental birds.