Identification of streptomycin-resistant strains of Erwinia amylovora in New York

• Published in: Phytopathology Vol. 98; no. 6; p. S208
• Main Authors: Russo, N L, Burr, T J, Breth, DI, Aldwinckle, H S
• Format: Journal Article
• Language: English
• Published: 01.06.2008
• Subjects: Erwinia amylovora; Malus
• ISSN: 0031-949X

Streptomycin is the most effective antibiotic registered for the control of fire blight on apple, a disease caused by Erwinia amylovora. Resistance surveys conducted between 2002-2006 produced the first authenticated report of streptomycin-resistant strains of E. amylovora in New York. Resistant strains were identified in two orchards in Wayne County. Resistance was based on the acquisition of the strA-strB gene pair, and not a spontaneous mutation of the streptomycin-binding site. Although common in epiphytic bacterial populations in NY, the strA-strB genes have only been associated with fire blight outbreaks in Michigan. Infected trees originated from Michigan, and it is likely bacteria were imported on infected nursery stock. Since orchard removal in 2003 no streptomycin-resistant E. amylovora have been identified in NY. The movement of infested plant material posses a great threat to the continued use of streptomycin as a routine application to control fire blight.