Molecular analysis of Salmonella enteritidis isolates from the Caribbean by pulsed-field gel electrophoresis

ABSTRACT

Using pulsed-field gel electrophoresis (PFGE), between 1987 and 1996 we analyzed Salmonella enteritidis isolates from gastroenteritis cases in four Caribbean countries Barbados, Saint Kitts and Nevis, Saint Lucia, and Trinidad and Tobago. We also determined the resistance of the isolates to 12 antimicrobial agents. Of the 129 isolates of S. enteritidis available for testing, DNA digested by Xbal revealed 13 distinctive PFGE patterns. The most prevalent Xbal PFGE patterns were group 1 (88 of 129 isolates, 68.2 percent) and group 2 (26 of 129, 20.2 percent). The patterns found among S. enteritidis isolates correlated with the geographical origin of the isolates. Of the 28 isolates from Barbados, 20 of them (71.4 percent) belonged to Xbal PFGE group 2, and of the 93 isolates from Trinidad and Tobago, 78 of them (83.9 percent) belonged to group 1. Spel digestion of S. enteritidis genome was not as discriminatory as Xbal. Overall, of the 129 isolates, 67 of them (51.9 percent) exhibited resistance to one or more of the 12 antimicrobial agents that we tested. The prevalence of resistance was 53.8 percent for the S. enteritidis isolates tested from Trinidad and Tobago, 50.0 percent for those from Barbados, 28.6 percent for those from Saint Lucia, and 100.0 percent for one isolate from the island of Saint Kitts. Resistance was highest to triple sulfur (59 of 129 isolates, 45.7 percent), followed by furadantoin (10 of 129, 7.8 percent), ampicillin (7 of 129, 5.4 percent), and carbamycin (5 of 129, 3.9 percent) (AU)