Epidemiological Tracing of Salmonella Enterica Serotype Abortusovis from Spanish Ovine Flocks by PFGE Fingerprinting

Salmonella enterica serotype Abortusovis, an ovine host-specific serotype, rare in most countries, is responsible for epidemic abortion episodes in Spain. With the aim of surveillance and detection of the spread of specific clones, 55 Abortusovis isolates collected during 1996-2001 from flocks in 11 provinces, were studied using XbaI-PFGE. Despite the fact that the strains were geographically and spatially related, PFGE demonstrated an epidemiologically acceptable discriminating power, identifying 20 clones (similarity, 52-96%). Clones Sabv6, 1, 5 were disseminated in seven, five and two areas respectively, while another 17 clones appeared in single places. Clones from nearby geographic regions showed a high relatedness (one band of difference in the PFGE profile) Sabv1-2-3, Sabv5-6, Sabv7-8, and Sabv13-14, suggesting a common ancestor. Co-isolation in the same flock (Sabv5-6, Sabv1-3, Sabv1-6) was detected. PFGE surveillance detected the predominance and widespread distribution of clone Sabv6 in 21 out of the 55 Abortusovis serotype episodes studied in Spain.