Pulsotyping of epidemic and sporadic Salmonella Choleraesuis isolates of Indian origin

Abstract

Restriction fragment analysis using 2 restriction enzymes, SpeI and XbaI was used to cluster and differentiate 13 outbreak and sporadic cases isolates of Salmonella Enterica serovar Choleraesuis by pulsed-field gel electrophoresis (PFGE) and to compare it with that of plasmid profiling. The fragment patterns obtained with these enzymes differed both in the numbers and the size of the fragments. SpeI digestion resulted in 5 different restriction patterns of 15-20 fragments between 45-800 kb. This enzyme was found to not only cluster and differentiate S. Choleraesuis recovered from outbreaks in pigs and pigmy hogs but also to differentiate outbreak isolates from sporadic cases. The distinguishable fragment pattern were found in between 225-104 bp and 90-45 bp. XbaI digestion yielded 3 different restriction patterns of 13-15 fragments between 45-800 kb. Although this enzyme was found to cluster and differentiate the outbreak isolates of pigs from that of pigmy hogs but failed to cluster outbreak isolates from those isolates from sporadic cases. The distinguishable fragment patterns were found in between 225-104 bp. Plasmid analysis revealed that all but 3 isoiates shared the same profile (30.0, 3.2, 2.6 MDa) irrespective of source of isolation which indicated its less usefulness for epidemiological studies. Data obtained in this study indicated that restriction analysis with SpeI may be used as a valuable tool for the epidemiological typing for the identification of source of infections caused by S. Choleraesuis.