<i>Staphylococcus aureus</i>
            Pathogenicity Island DNA Is Packaged in Particles Composed of Phage Proteins

Tormo, María Ángeles; Ferrer, Milagros; Maiques, Elisa; Úbeda, Carles; Selva, Laura; Lasa, Íñigo; Calvete, Juan J.; Novick, Richard P.; Penadés, José R.

doi:10.1128/jb.01349-07

Cited by 93 publications

(98 citation statements)

References 20 publications

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“…Typically genes that are known or proposed to endow enhanced fitness or virulence upon their host and that are carried by many temperate phage of low-GϩC bacteria, are located between the gene encoding endolysin and the right phage attachment site, e.g., S. aureus immune escape and Panton-Valentine leukocidin (PVL) genes (14,43,54,55). Examination of the eight E. faecalis phage genomes reveals that ⌽FL1 to 3, but not ⌽FL4A, possess either one or two coding sequences located in this region.…”

Section: Resultsmentioning

confidence: 99%

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Comparative Genomics and Transduction Potential of Enterococcus faecalis Temperate Bacteriophages

et al. 2010

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To determine the relative importance of temperate bacteriophage in the horizontal gene transfer of fitness and virulence determinants of Enterococcus faecalis, a panel of 47 bacteremia isolates were treated with the inducing agents mitomycin C, norfloxacin, and UV radiation. Thirty-four phages were purified from culture supernatants and discriminated using pulsed-field gel electrophoresis (PFGE) and restriction mapping. From these analyses the genomes of eight representative phages were pyrosequenced, revealing four distinct groups of phages. Three groups of phages, ⌽FL1 to 3, were found to be sequence related, with ⌽FL1A to C and ⌽FL2A and B sharing the greatest identity (87 to 88%), while ⌽FL3A and B share 37 to 41% identity with ⌽FL1 and 2. ⌽FL4A shares 3 to 12% identity with the phages ⌽FL1 to 3. The ⌽FL3A and B phages possess a high DNA sequence identity with the morphogenesis and lysis modules of Lactococcus lactis subsp. cremoris prophages. Homologs of the Streptococcus mitis platelet binding phage tail proteins, PblA and PblB, are encoded on each sequenced E. faecalis phage. Few other phage genes encoding potential virulence functions were identified, and there was little evidence of carriage of lysogenic conversion genes distal to endolysin, as has been observed with genomes of many temperate phages from the opportunist pathogens Staphylococcus aureus and Streptococcus pyogenes. E. faecalis JH2-2 lysogens were generated using the eight phages, and these were examined for their relative fitness in Galleria mellonella. Several lysogens exhibited different effects upon survival of G. mellonella compared to their isogenic parent. The eight phages were tested for their ability to package host DNA, and three were shown to be very effective for generalized transduction of naive host cells of the laboratory strains OG1RF and JH2-2.Enterococcus faecalis is a member of the natural flora of humans and colonizes the gastrointestinal and vaginal tracts and the oral cavity. In recent years it has emerged as an important opportunistic nosocomial pathogen and is a causative agent of bacteremia, infective endocarditis, and surgical wound and urinary tract infections. The accumulation of acquired antibiotic resistance determinants, in addition to its intrinsic resistance and tenacity, has given rise to the evolution of clinical isolates of E. faecalis that are therapeutically problematic (19). Greater notoriety was afforded to this species following the observed transfer of the conjugative transposon Tn1546 to Staphylococcus aureus, imparting vancomycin resistance (11). Subsequent analysis has revealed that multiple independent E. faecalis-dependent vanA transfers had occurred in the United States prior to 2007 (50). This places enterococci in an important and dynamic position within the health care system, warranting their increased study.The specific determinants that are proposed to contribute to the virulence of E. faecalis are not universally present, and expression of the cognate genes is variable (21, 37). For exa...

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Section: Resultsmentioning

confidence: 99%

“…In Staphylococcus aureus, bacteriophages encode and mobilize an impressive array of immune evasion genes (54,55) and Panton-Valentine leukocidin (43). Several bacteriophage-encoded virulence determinants also contribute to pathogenesis in group A Streptococcus (2,3,4).…”

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Comparative Genomics and Transduction Potential of Enterococcus faecalis Temperate Bacteriophages

et al. 2010

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“…Given the overall frequency of overall prophage carriage as shown by the multiple examples found in all of the sequenced genomes, this mechanism could well be generalized transduction. However, it is possible that there is some unknown packaging mechanism, perhaps employing a helper phage, that could generate infectious particles that could spread the phages in a manner similar to packaging and dissemination of the Staphylococcus aureus pathogenicity islands (57).…”

Section: ϫ4mentioning

confidence: 99%

Phage-Associated Mutator Phenotype in Group A Streptococcus

et al. 2008

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Defects in DNA mismatch repair (MMR) occur frequently in natural populations of pathogenic and commensal bacteria, resulting in a mutator phenotype. We identified a unique genetic element in Streptococcus pyogenes strain SF370 that controls MMR via a dynamic process of prophage excision and reintegration in response to growth. In S. pyogenes, mutS and mutL are organized on a polycistronic mRNA under control of a common promoter. Prophage SF370.4 is integrated between the two genes, blocking expression of the downstream gene (mutL) and resulting in a mutator phenotype. However, in rapidly growing cells the prophage excises and replicates as an episome, allowing mutL to be expressed. Excision of prophage SF370.4 and expression of MutL mRNA occur simultaneously during early logarithmic growth when cell densities are low; this brief window of MutL gene expression ends as the cell density increases. However, detectable amounts of MutL protein remain in the cell until the onset of stationary phase. Thus, MMR in S. pyogenes SF370 is functional in exponentially growing cells but defective when resources are limiting. The presence of a prophage integrated into the 5 end of mutL correlates with a mutator phenotype (10 ؊7 to 10 ؊8 mutation/generation, an approximately a 100-fold increase in the rate of spontaneous mutation compared with prophage-free strains [10 ؊9 to 10 ؊10 mutation/generation]). Such genetic elements may be common in S. pyogenes since 6 of 13 completed genomes have related prophages, and a survey of 100 strains found that about 20% of them are positive for phages occupying the SF370.4 attP site. The dynamic control of a major DNA repair system by a bacteriophage is a novel method for achieving the mutator phenotype and may allow the organism to respond rapidly to a changing environment while minimizing the risks associated with long-term hypermutability.

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“…For example, in Vibrio cholerae the cholera toxin, a key virulence determinant, is encoded in the genome of the temperate phage ΦCTX 103 . As another example, Staphylococcus aureus pathogenicity islands (SaPIs) excise from the chromosome and replicate following induction by an infecting phage, and the SaPI DNA is packaged in modified phage particles and transferred to other S. aureus cells 104,105 and even to species from other genera 106 .…”

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confidence: 99%

Gene transfer agents: phage-like elements of genetic exchange

2012

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Horizontal gene transfer is important in the evolution of bacterial and archaeal genomes. An interesting genetic exchange process is carried out by diverse phage-like gene transfer agents (GTAs) that are found in a wide range of prokaryotes. Although GTAs resemble phages, they lack the hallmark capabilities that define typical phages, and they package random pieces of the producing cell's genome. In this Review, we discuss the defining characteristics of the GTAs that have been identified to date, along with potential functions for these agents and the possible evolutionary forces that act on the genes involved in their production.The prevalence of horizontal gene transfer (HGT), in which DNA is exchanged between closely or distantly related lineages, has altered the way we think about evolution 1,2 , having profound effects on our views of the evolutionary relationships among living organisms. It has caused a shift from a bifurcating 'tree of life' view to a 'net of life' or 'web of life' view [3][4][5] , in which "highways of gene sharing" (REF. 6) represent major connections, with genes (or DNA segments) viewed as "public goods, available for all organisms to integrate into their genomes" (REF. 7). HGT occurs within and between all three domains of life, and it has been estimated that 0.05-80% of genes in bacterial and archaeal genomes have been affected by HGT, depending on the analytical method used and the genome analysed [8][9][10] . Although HGT is widespread, it is not random: patterns of preferential gene exchange among specific groups of organisms that share ancestry or habitat have been * Present address. aslang@mun.ca; olgazh@dartmouth.edu; j.beatty@mail.ubc.ca Competing interests statementThe authors declare no competing financial interests. 6,9,11,12 . Such patterns are probably a consequence of existing barriers to HGT, which have been reviewed in detail elsewhere 13,14 . FURTHER INFORMATIONAlthough we have known about some HGT mechanisms for decades, novel processes that expand the existing repertoire of gene exchange methods are continually being identified. Transformation was the first mechanism of gene exchange to be discovered 15 , wherein DNA is taken up directly from the environment (reviewed elsewhere 16,17 ). In transduction, DNA transfer is mediated by viral particles (BOX 1). In conjugation, which was discovered in the 1940s 18 , DNA is transferred from a donor to a recipient cell during cell-to-cell contact; conjugation is used in the transfer of plasmids, transposons, integrons, and integrative and conjugative elements (ICEs) [19][20][21] . There are other modes of gene exchange that do not fit well into any of these three canonical mechanisms, including temporary cell fusion followed by chromosomal recombination and plasmid exchange 22 , intercellular connection through nanotubes 23 , and the release of membrane vesicles containing chromosomal, plasmid and phage DNA that can then merge with nearby cells 24 . In addition, a novel mechanism of gene transfer that has feature...

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Staphylococcus aureus Pathogenicity Island DNA Is Packaged in Particles Composed of Phage Proteins

Cited by 93 publications

References 20 publications

Comparative Genomics and Transduction Potential of Enterococcus faecalis Temperate Bacteriophages

Comparative Genomics and Transduction Potential of Enterococcus faecalis Temperate Bacteriophages

Phage-Associated Mutator Phenotype in Group A Streptococcus

Gene transfer agents: phage-like elements of genetic exchange

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