Identification of Virulence Genes in Enterococcus faecalis by Differential Display Polymerase Chain Reaction

Abstract

Enterococcal bacteremia and other important clinical sequelae are associated with significant morbidity and mortality, particularly among hospitalized and immunocompromised patients⁴. In recent years, enterococci have emerged among the leading causes of nosocomial infection. This continuing trend, coupled with the emergence and spread of enterococcal strains with intrinsic and acquired resistance to a wide variety of antimicrobial agents, has precipitated the need to identify genes involved in the transition from colonization to disease, whose products may serve as novel targets for antimicrobial action. Because relatively little is known about the factors that contribute to the ability of enterococci to cause infections in humans, it was of interest to develop a means for identification of genes that are selectively expressed in different environments. To identify differential expression of genes, we adapted a method more commonly used in the study of eukaryotic gene expression—differential display PCR or RNA arbitrarily primed PCR⁶. In the present study, the utility of this method has been shown in experiments that demonstrated differential expression of genes by E. faecalis cultured in standard lab media under aerobic vs. anaerobic conditions.