The specificity of PCR-based protocols for detection of Erwinia amylovora

An evaluation of seven published conventional PCR protocols used for the detection of Erwinia amylovora has shown that six out of the seven protocols tested were not specific for all strains of E. amylovora. A collection of 40 genetically diverse strains of E. amylovora and 55 geographically diverse bacteria that are closely related or share the same ecological niche as E. amylovora were used to test the seven PCR protocols. All bacteria were tested for virulence by inoculation of immature pear fruit and for cultural characteristics on selective media. Only one PCR protocol, Taylor et al. (2001), was specific for all strains of E. amylovora and was able to differentiate E. amylovora from all other bacteria tested. Diagnostic laboratories may need to review their testing procedures in light of these findings.