title: Matrix-assisted laser desorption ionization time-of-flight mass spectrometry for rapid identification of Brachyspira species isolated from swine, including the newly described "Brachyspira hampsonii".
abstract: The Brachyspira species traditionally associated with swine dysentery and other diarrheal diseases in pigs are Brachyspira hyodysenteriae, Brachyspira pilosicoli, and, to a lesser extent, Brachyspira murdochii. "Brachyspira hampsonii" is a recently proposed novel species that causes clinical disease similar to that caused by B. hyodysenteriae. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) systems are increasingly available in veterinary diagnostic laboratories, are less expensive, and are faster than traditional microbiological and molecular methods for identification. Thirty-three isolates associated with Brachyspira species of importance to swine were added to an existing MALDI-TOF MS database library. In total, species included in the library were: B. hyodysenteriae, "B. hampsonii" clades I and II, Brachyspira innocens, Brachyspira intermedia, B. murdochii, and B. pilosicoli. A comparison between MALDI-TOF MS and nox sequencing was completed on 176 field isolates. Of the 176 field isolates, 174 (98.9%) matched species identification by both methods. Thirty field isolates were identified by both methods as "B. hampsonii". Twenty-seven of the 30 (90%) "B. hampsonii" field isolates matched clade designation in both assays. The nox sequencing identified 26 as "B. hampsonii" clade I and 4 as clade II. Comparatively, MALDI-TOF MS identified 25 of the 30 as "B. hampsonii" clade I and 5 as clade II. The current study indicates MALDI-TOF MS is a reliable tool for the identification of swine Brachyspira species; however, final clade designation for "B. hampsonii" may still require molecular techniques.
authors.affiliation: Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University, Ames, IA hwarneke@iastate.edu.
authors.forename: Hallie L
authors.initials: HL
authors.lastname: Warneke
authors.affiliation: Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University, Ames, IA.
authors.forename: Joann M
authors.initials: JM
authors.lastname: Kinyon
authors.affiliation: Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University, Ames, IA.
authors.forename: Leslie P
authors.initials: LP
authors.lastname: Bower
authors.affiliation: Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University, Ames, IA.
authors.forename: Eric R
authors.initials: ER
authors.lastname: Burrough
authors.affiliation: Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University, Ames, IA.
authors.forename: Timothy S
authors.initials: TS
authors.lastname: Frana
mesh_terms: D000818:Animals; D015373:Bacterial Typing Techniques / Q000379:methods / Q000662:veterinary*; D017400:Brachyspira / Q000145:classification / Q000302:isolation & purification*; D016905:Gram-Negative Bacterial Infections / Q000382:microbiology / Q000662:veterinary*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000662:veterinary*; D013552:Swine; D013553:Swine Diseases / Q000175:diagnosis / Q000382:microbiology*
keywords: Brachyspira; matrix-assisted laser desorption ionization time-of-flight mass spectrometry