PFGE XbaI® Indistinguishable properties of Salmonella Kastrup and Salmonella Larochelle isolates at beef processing and distribution continuum

Abstract

Salmonellosis is a major cause of foodborne illnesses in humans throughout the world. Pulsed field gel electrophoresis (PFGE) is a commonly used tool for epidemiological survey and source tracking of Salmonella strains isolated from various sources. A total of 237 samples from various sources were collected at abattoir and butcheries in Ethiopia from December 2011 to April 2012. Isolates of Salmonella Kastrup (n = 3) and Salmonella Larochelle (n = 11) were characterized for antimicrobial resistance using disc diffusion and for genotypic profiles using PFGE XbaI®. Salmonella Kastrup and S. Larochelle were isolated from 1.3% and 4.6% of total samples (n = 237) examined. Except for water samples (n = 12) and truck swabs (n=11), all other sample sources were positive for one or more of S. Kastrup and S. Larochelle. Salmonella Kastrup was isolated in Ethiopia for the first time. Salmonella isolates from both Kastrup and Larochelle serotypes showed similar antimicrobial resistance profiles. Two pulsotypes consisting of the same three S. Kastrup and 10 S. Larochelle cluster and second cluster consisting of one S. Larochelle were identified at 1.5% and 1% band positions tolerance by unweighted-pair group method (UPGM) and showed ≥91% similarity. S. Kastrup and S. Larochelle isolates showed similar antimicrobial resistance profiles with indistinguishable PFGE XbaI® patterns indicating possible clonal spread of the isolates along beef processing and distribution continuum.

Key words: Salmonella; PFGE; Antimicrobial resistance; Beef; Ethiopia