Species identification of erythromycin-resistant Campylobacter isolates and optimization of a duplex PCR for rapid detection

This study describes the approach used to verify the species identity of 23 erythromycin-resistant Campylobacter isolates whose identity was initially determined based mainly on the results of the rapid hippurate hydrolysis test or the results of the API-Campy identification system. Species identification of the isolates investigated was confirmed by repeating hippurate hydrolysis using a modification of the rapid hydrolysis test, in addition to performing three genetic-based assays. The original identification was verified in 69.6% of the isolates. The remaining isolates showed discrepancies in identity as determined by results of the identification assays performed. A duplex PCR assay, targeting the hipO and aspA genes, indicated the existence of mixed cultures of C. jejuni and C. coli in the frozen stocks of two of these isolates.