Classification of Salmonella enterica serotypes from Australian poultry using repetitive sequence‐based PCR

Aims:  To evaluate a semi‐automated repetitive extragenic palindromic sequence‐based PCR (rep‐PCR) system for the classification of Salmonella serotypes from Australian poultry. Methods and Results:  Using a DNA fingerprint library within the DiversiLab ® System, four separate databases were constructed (serogroup B, C, E and Other). These databases contained 483 serologically confirmed (reference laboratory) Salmonella isolates. A blinded set of Salmonella cultures ( n  =   155) were typed by rep‐PCR, matched against the internal library and compared with traditional serotyping. The predicted (Kullback–Leibler) serotype of 143 (92·3%) isolates matched traditional typing ( P  <   0·05). Of the 12 (7·7%) remaining isolates, ten (6·5%) resulted in ‘No Match’, one (0·65%) was incorrectly matched to the library ( Salm.  subsp 1 ser 4,12:‐:‐), and the other (0·65%) was referenced as Salm.  ser. Sofia, whereas rep‐PCR and in‐house serotyping concurred as Salmonella serovar Typhimurium. Financial analysis showed higher material cost (215%) and a lower labour component (47·5%) for rep‐PCR compared with serotyping. Conclusion:  The DiversiLab ® System, with serogroup databases, was successfully implemented as an adjunct for reference serotyping of Salmonella enterica . Significance and Impact of the Study:  The DiversiLab ® System platform is a cost‐effective and easy‐to‐use system, which can putatively determine Salmonella enterica serotypes within a few hours.