title: Isolation and characterization of a 6/85-like Mycoplasma gallisepticum from commercial laying hens.
abstract: 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.
authors.affiliation: Department of Avian Medicine, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA.
authors.forename: S J
authors.initials: SJ
authors.lastname: Throne Steinlage
authors.forename: N
authors.initials: N
authors.lastname: Ferguson
authors.forename: J E
authors.initials: JE
authors.lastname: Sander
authors.forename: M
authors.initials: M
authors.lastname: García
authors.forename: S
authors.initials: S
authors.lastname: Subramanian
authors.forename: V A
authors.initials: VA
authors.lastname: Leiting
authors.forename: S H
authors.initials: SH
authors.lastname: Kleven
mesh_terms: D000400:Air Sacs / Q000382:microbiology / Q000473:pathology; D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology; D001428:Bacterial Vaccines / Q000009:adverse effects* / Q000276:immunology; D002645:Chickens / Q000382:microbiology*; D005260:Female; D009174:Mycoplasma / Q000145:classification* / Q000276:immunology / Q000302:isolation & purification* / Q000472:pathogenicity; D017422:Sequence Analysis, DNA; D014132:Trachea / Q000382:microbiology / Q000473:pathology
chemical_list: D000907:Antibodies, Bacterial; D001428:Bacterial Vaccines