title: Phenotypic characterization and ERIC-PCR based genotyping of Paenibacillus larvae isolates recovered from American foulbrood outbreaks in honey bees from Italy.
abstract: BACKGROUND
  Paenibacillus larvae is the etiological agent of American foulbrood (AFB), a widespread and severe bacterial brood disease of honey bees. The genomic characterization of P. larvae strains by enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) is able to differentiate four genotypes (ERIC I, ERIC II, ERIC III, ERIC IV). The information on the presence of P. larvae ERIC genotypes worldwide is few.
  
  
  OBJECTIVE
  We have characterized P. larvae strains isolated in Italy from AFB outbreaks to obtain information on ERIC genotypes and phenotypes of the strains circulating in the country.
  
  
  METHODS
  A total of 117 P. larvae isolates from 115 AFB outbreaks occurring in 2008-2012 were subjected to phenotypic and genetic characterization.
  
  
  RESULTS
  The genomic characterization allowed the identification of ERIC I and ERIC II genotypes. Examining the data of Northern and Central Italy separately it was noted that in Northern Italy most outbreaks were caused by the ERIC I genotype (78.6%), followed by the ERIC II genotype (18.6%) and by co-infections (ERIC I + ERIC II) (2.6%). In Central Italy, only outbreaks caused by the ERIC I genotype were observed. With regard to phenotypic characteristics all examined strains of ERIC II genotype fermented fructose while no strains of ERIC I genotype possessed this ability.
  
  
  CONCLUSIONS
  Both P. larvae ERIC I and ERIC II genotypes were isolated from the AFB outbreaks, but ERIC II genotype was isolated only in Northern Italy. The fermentation of fructose seems to be a genotype-specific biochemical marker.
authors.affiliation: a Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna , Sezione di Modena , Modena , Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Bassi
authors.forename: Giovanni
authors.initials: G
authors.lastname: Formato
authors.forename: Marcella
authors.initials: M
authors.lastname: Milito
authors.forename: Karin
authors.initials: K
authors.lastname: Trevisiol
authors.forename: Cristian
authors.initials: C
authors.lastname: Salogni
authors.forename: Elena
authors.initials: E
authors.lastname: Carra
mesh_terms: D000818:Animals; D001516:Bees / Q000382:microbiology*; D004196:Disease Outbreaks / Q000662:veterinary; D005632:Fructose / Q000378:metabolism; D005819:Genetic Markers; D005838:Genotype; D007558:Italy / Q000453:epidemiology; D056507:Paenibacillus / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D010641:Phenotype; D016133:Polymerase Chain Reaction / Q000379:methods / Q000662:veterinary
chemical_list: D005819:Genetic Markers; D005632:Fructose
keywords: American foulbrood; Apis mellifera; ERIC–PCR; Paenibacillus larvae; epidemiology; genotyping; honey bees; phenotyping