title: Erysipelothrix rhusiopathiae: genetic characterization of midwest US isolates and live commercial vaccines using pulsed-field gel electrophoresis.
abstract: This is the first report of molecular characterization of US erysipelas field isolates and vaccine strains of Erysipelothrix rhusiopathiae by pulsed-field gel electrophoresis (PFGE). Erysipelas in pigs is mainly caused by E. rhusiopathiae serotypes 1a, 1b, and 2. In 2001, erysipelas reemerged as a clinical problem in pigs in the midwestern United States. In this work 90 erysipelas isolates (58 recent and 28 archived field isolates as well as 4 live-vaccine strains) were genetically characterized. Because of the limited availability of antiserum, 74/90 isolates (44/58 recent isolates) were serotyped. The serotype of the majority (79.6%) of the 44 recent isolates tested was determined to be 1a, 13.6% were serotype 1b, and 6.8% of recent isolates were serologically untypeable. Among all 90 isolates, 23 different PFGE patterns were identified. There were 43 isolates identified as serotype 1a with 4 genetic patterns: 38/43, 1A(I); 3/43, 1A(III); 1/43, 1B(V); and 1/43, 3B. Sixteen serotype 1b isolates had 11 unique genetic patterns: 4/16 were genotype 1B(III), 2/16 were genotype 3A(I), and 1/16 was in genotype groups 1A(V), 1A(VI), 1A(VII), 1B(I), 1B(IV), 1B(VII), 2, 4, and 5. Six genetic patterns were distinguished among the 10 serotype 2 isolates: 1A(IV) (1/10), 1A(V) (1/10), 1B(VI) (1/10), 2 (4/10), 7 (1/10), and 8 (2/8). Erysipelas vaccine strains (modified live) were similar to each other but different from current field strains, sharing 78.6% identity with the most prevalent genotype 1A(I) based on the PFGE-SmaI pattern. Compared with serotyping, PFGE genotyping is a more distinguishing technique, easy to perform and not dependent on the limited availability of antiserum.
authors.affiliation: Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University, Ames, IA 50011, USA.
authors.forename: T
authors.initials: T
authors.lastname: Opriessnig
authors.forename: L J
authors.initials: LJ
authors.lastname: Hoffman
authors.forename: D L
authors.initials: DL
authors.lastname: Harris
authors.forename: S B
authors.initials: SB
authors.lastname: Gaul
authors.forename: P G
authors.initials: PG
authors.lastname: Halbur
mesh_terms: D000818:Animals; D001428:Bacterial Vaccines / Q000235:genetics* / Q000276:immunology; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004196:Disease Outbreaks / Q000662:veterinary; D016521:Electrophoresis, Gel, Pulsed-Field / Q000662:veterinary; D004888:Erysipelothrix / Q000235:genetics* / Q000276:immunology / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests / Q000662:veterinary; D015146:Midwestern United States / Q000453:epidemiology; D010802:Phylogeny; D012703:Serotyping / Q000662:veterinary; D013552:Swine; D013554:Swine Erysipelas / Q000453:epidemiology / Q000382:microbiology; D014613:Vaccines, Attenuated / Q000235:genetics / Q000276:immunology
chemical_list: D001428:Bacterial Vaccines; D004269:DNA, Bacterial; D014613:Vaccines, Attenuated