Virulence Genes amongEnterococcus faecalisandEnterococcus faeciumIsolated from Coastal Beaches and Human and Nonhuman Sources in Southern California and Puerto Rico

Abstract

MostEnterococcus faecalisandE. faeciumare harmless to humans; however, strains harboring virulence genes, includingesp, gelE, cylA, asa1, andhyl, have been associated with human infections.E. faecalisandE. faeciumare present in beach waters worldwide, yet little is known about their virulence potential. Here, multiplex PCR was used to compare the distribution of virulence genes amongE. faecalisandE. faeciumisolated from beaches in Southern California and Puerto Rico to isolates from potential sources including humans, animals, birds, and plants. All five virulence genes were found inE. faecalisandE. faeciumfrom beach water, mostly amongE. faecalis.gelEwas the most common among isolates from all source types. There was a lower incidence ofasa1,esp,cylA, andhylgenes among isolates from beach water, sewage, septage, urban runoff, sea wrack, and eelgrass as compared to human isolates, indicating that virulent strains ofE. faecalisandE. faeciummay not be widely disseminated at beaches. A higher frequency ofasa1andespamongE. faecalisfrom dogs and ofasa1among birds (mostly seagull) suggests that further studies on the distribution and virulence potential of strains carrying these genes may be warranted.