Molecular genotyping of Salmonella enterica Abortusovis by pulsed field gel electrophoresis

Genotyping of Salmonella strains is an important tool to discriminate among isolates and to improve epidemiological studies when an outbreak occurs. No phagetyping scheme is available for Salmonella enterica subsp. enterica serovar Abortusovis (SAO) and molecular methods previously used were not standardized and were time consuming. Among the DNA-based methods of genotyping, pulsed field gel electrophoresis (PFGE) is currently in use to subtype Salmonella isolates. In this study we evaluated the feasibility of genotyping of SAO by XbaI and BlnI restrictions. Separation of restricted fragments was performed by PFGE. To test the possibility to apply this methodology to epidemiological investigation, a collection of 38 SAO strains isolated in different regions of Italy were analyzed. Eighteen and 29 different PFGE profiles were defined for XbaI and BlnI digestions, respectively. The method demonstrated an adequate typing ability and an excellent discriminatory power. Results from this study show that PFGE may represent a powerful tool to discriminate within the SAO serovar, and provide useful information in support of traditional epidemiological investigations. In particular, this method could be used to identify the origin of infection during outbreaks within a single flock or in different herds.