Genotypic comparison of Pantoea agglomerans plant and clinical strains

Majority of the clinical isolates from culture collections were found to be improperly designated as P. agglomerans after sequence analysis. The frequent taxonomic rearrangements underwent by the Enterobacter agglomerans/Erwinia herbicola complex may be a major problem in assessing clinical associations within P. agglomerans. In the P. agglomerans sensu stricto (in the stricter sense) group, there was no discrete clustering of clinical/biocontrol strains and no marker was identified that was uniquely associated to clinical strains. A putative biocontrol-specific fAFLP marker was identified only in biocontrol strains. The partial ORF located in this band corresponded to an ABC transporter that was found in all P. agglomerans strains.Taxonomic mischaracterization was identified as a major problem with P. agglomerans, and current techniques removed a majority of clinical strains from this species. Although clear discrimination between P. agglomerans plant and clinical strains was not obtained with phylogenetic analysis, a single marker characteristic of biocontrol strains was identified which may be of use in strain biosafety determinations. In addition, the lack of Koch's postulate fulfilment, rare retention of clinical strains for subsequent confirmation, and the polymicrobial nature of P. agglomerans clinical reports should be considered in biosafety assessment of beneficial strains in this species.Pantoea agglomerans (Beijerinck 1888) comb. nov. [1], formerly Enterobacter agglomerans (Beijerinck 1888) Ewing and Fife (1972), Erwinia herbicola (L？hnis 1911) Dye 1964 or Erwinia milletiae (Kawakami and Yoshida 1920) Magrou 1937, is a Gram-negative bacterium that belongs to the family of Enterobacteriaceae. P. agglomerans is primarily a plant epiphyte [2-4] commonly found in diverse ecological niches including aquatic environments, soil or sediments [5-7]. Several strains of P. agglomerans are sold as commercial biological control agents (BCAs) against the fire blight p