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"

• Published in: Journal of veterinary diagnostic investigation Vol. 26; no. 5; p. 635
• Main Authors: Warneke, Hallie L, Kinyon, Joann M, Bower, Leslie P, Burrough, Eric R, Frana, Timothy S
• Format: Journal Article
• Language: English
• Published: United States 01.09.2014
• Subjects: Animals; Bacterial Typing Techniques - methods; Bacterial Typing Techniques - veterinary; Brachyspira - classification; Brachyspira - isolation & purification; Gram-Negative Bacterial Infections - microbiology; Gram-Negative Bacterial Infections - veterinary; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization - veterinary; Swine; Swine Diseases - diagnosis; Swine Diseases - microbiology; Brachyspira; matrix-assisted laser desorption ionization time-of-flight mass spectrometry
• ISSN: 1943-4936
• DOI: 10.1177/1040638714541114

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.