Enterococcus faecalis Prophage Dynamics and Contributions to Pathogenic Traits

Abstract

Polylysogeny is frequently considered to be the result of an adaptive evolutionary process in which prophages confer fitness and/or virulence factors, thus making them important for evolution of both bacterial populations and infectious diseases. The Enterococcus faecalis V583 isolate belongs to the high-risk clonal complex 2 that is particularly well adapted to the hospital environment. Its genome carries 7 prophage-like elements (V583-pp1 to -pp7), one of which is ubiquitous in the species. In this study, we investigated the activity of the V583 prophages and their contribution to E. faecalis biological traits. We systematically analyzed the ability of each prophage to excise from the bacterial chromosome, to replicate and to package its DNA. We also created a set of E. faecalis isogenic strains that lack from one to all six non-ubiquitous prophages by mimicking natural excision. Our work reveals that prophages of E. faecalis V583 excise from the bacterial chromosome in the presence of a fluoroquinolone, and are able to produce active phage progeny. Intricate interactions between V583 prophages were also unveiled: i) pp7, coined EfCIV583 for E. faecalis chromosomal island of V583, hijacks capsids from helper phage 1, leading to the formation of distinct virions, and ii) pp1, pp3 and pp5 inhibit excision of pp4 and pp6. The hijacking exerted by EfCIV583 on helper phage 1 capsids is the first example of molecular piracy in Gram positive bacteria other than staphylococci. Furthermore, prophages encoding platelet-binding-like proteins were found to be involved in adhesion to human platelets, considered as a first step towards the development of infective endocarditis. Our findings reveal not only a role of E. faecalis V583 prophages in pathogenicity, but also provide an explanation for the correlation between antibiotic usage and E. faecalis success as a nosocomial pathogen, as fluoriquinolone may provoke release of prophages and promote gene dissemination among isolates.

Impact of Spontaneous Prophage Induction on the Fitness of Bacterial Populations and Host-Microbe Interactions

“…E. faecalis strain V583 is polylysogenic for 7 prophage-like elements (termed V583-pp1 to V583-pp7) ( Table 1). It was shown that three of these, pp1, pp4, and pp6, are important for adhesion to human platelets, which is possibly achieved by expression of the genes encoding PblA and PblB which are homologous to those of S. mitis (84). Thus, these examples nicely reveal that SPI triggered lysis of a small fraction of cells, possibly promoting the adhesion of the remaining noninduced part of the population.…”

Consensus conference on TIPS management: Techniques, indications, contraindications

“…Hemodynamic non-responders to secondary FLT should be considered earlier for TIPS. Preliminary, albeit uncontrolled, data indicate that allocation of these patients to TIPS reduces rebleeding rate and bleeding-associated mortality [5, 97,106,[110][111][112][113].…”

Whole-genome mapping of 5′ RNA ends in bacteria by tagged sequencing: a comprehensive view in Enterococcus faecalis

“…The inner plot visually describes with vertical blue lines the location and importance of antisense organizations detected (see the ppRNome browser for details). On the chromosome, the pathogenicity island (red) and other mobile genetic elements are annotated on the chromosome, i.e., efaC1/C2 (dark green), vancomycin resistance region (orange), and the six prophages (bright green) (Lepage et al 2006;Matos et al 2013). …”