1887

Abstract

Despite the existence of various virulence factors in the genus, enterococcal virulence is still a debated issue. A main consideration is the detection of the same virulence genes in strains isolated from nosocomial or community-acquired infections, and from food products. The goal of this study was to evaluate the roles of two well-characterized enterococcal virulence factors, Fsr and gelatinase, in the potential virulence of food strains. Virulence of unrelated isolates, including dairy strains carrying and operons, was compared in the insect model. dairy strains were able to kill larvae and were as virulent as strain OG1RF, one of the most widely used for virulence studies. In contrast, and strains were avirulent or poorly virulent for . To evaluate the role of and in virulence of dairy strains, both genes were deleted independently in two strains. The Δ and Δ deletion mutants both produced a gelatinase-negative phenotype. Although both mutations significantly attenuated virulence in , the Δ strains were more strongly attenuated. These results agree with previous findings suggesting the involvement of in the control of other cell functions relevant to virulence. Our work demonstrates that the presence of functional , and to a lesser extent , in dairy enterococci should be considered with caution.

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2009-11-01
2020-07-12
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References

  1. Aarestrup F. M., Butaye P., Witte W.. 2002; Nonhuman reservoirs of enterococci. In The Enterococci: Pathogenesis, Molecular Biology and Antibiotic Resistance pp55–99 Edited by Gilmore M. S.. Washington, DC: American Society for Microbiology;
    [Google Scholar]
  2. Alves P. I., Martins M. P., Semedo T., Figueiredo Marques J. J., Tenreiro R., Barreto Crespo M. T.. 2004; Comparison of phenotypic and genotypic taxonomic methods for the identification of dairy enterococci. Antonie Van Leeuwenhoek85:237–252
    [Google Scholar]
  3. Bouillaut L., Ramarao N., Buisson C., Gilois N., Gohar M., Lereclus D., Nielsen-LeRoux C.. 2005; FlhA influences transcription of PlcR regulated genes, protein production, and virulence. Appl Environ Microbiol71:8903–8910
    [Google Scholar]
  4. Bourgogne A., Hilsenbeck S. G., Dunny G. M., Murray B. E.. 2006; Comparison of OG1RF and an isogenic fsrB deletion mutant by transcriptional analysis: the Fsr system of Enterococcus faecalis is more than the activator of gelatinase and serine protease. J Bacteriol188:2875–2884
    [Google Scholar]
  5. Bourgogne A., Garsin D. A., Qin X., Singh K. V., Sillanpaa J., Yerrapragada S., Ding Y., Dugan-Rocha S., Buhay C.. other authors 2008; Large scale variation in Enterococcus faecalis illustrated by the genome analysis of strain OG1RF. Genome Biol9:R110
    [Google Scholar]
  6. Brennan M., Thomas D. Y., Whiteway M., Kavanagh K.. 2002; Correlation between virulence of Candida albicans mutants in mice and Galleria mellonella larvae. FEMS Immunol Med Microbiol34:153–157
    [Google Scholar]
  7. Brinster S., Furlan S., Serror P.. 2007; C-terminal WxL domain mediates cell wall binding in Enterococcus faecalis and other Gram-positive bacteria. J Bacteriol189:1244–1253
    [Google Scholar]
  8. Choi J. Y., Sifri C. D., Goumnerov B. C., Rahme L. G., Ausubel F. M., Calderwood S. B.. 2002; Identification of virulence genes in a pathogenic strain of Pseudomonas aeruginosa by representational difference analysis. J Bacteriol184:952–961
    [Google Scholar]
  9. Cotter G., Doyle S., Kavanagh K.. 2000; Development of an insect model for the in vivo pathogenicity testing of yeasts. FEMS Immunol Med Microbiol27:163–169
    [Google Scholar]
  10. Dower W. J., Miller J. F., Ragsdale C. W.. 1988; High efficiency transformation of E. coli by high voltage electroporation. Nucleic Acids Res16:6127–6145
    [Google Scholar]
  11. Dunny G. M., Brown B. L., Clewell D. B.. 1978; Induced cell aggregation and mating in Streptococcus faecalis: evidence for a bacterial sex pheromone. Proc Natl Acad Sci U S A75:3479–3483
    [Google Scholar]
  12. Dunny G. M., Lee L. N., LeBlanc D. J.. 1991; Improved electroporation and cloning vector system for Gram-positive bacteria. Appl Environ Microbiol57:1194–1201
    [Google Scholar]
  13. Eaton T. J., Gasson M. J.. 2001; Molecular screening of Enterococcus virulence determinants and potential for genetic exchange between food and medical isolates. Appl Environ Microbiol67:1628–1635
    [Google Scholar]
  14. Engelbert M., Mylonakis E., Ausubel F. M., Calderwood S. B., Gilmore M. S.. 2004; Contribution of gelatinase, serine protease, and fsr to the pathogenesis of Enterococcus faecalis endophthalmitis. Infect Immun72:3628–3633
    [Google Scholar]
  15. Fares H., Greenwald I.. 2001; Genetic analysis of endocytosis in Caenorhabditis elegans: coelomocyte uptake defective mutants. Genetics159:133–145
    [Google Scholar]
  16. Fedhila S., Daou N., Lereclus D., Nielsen-LeRoux C.. 2006; Identification of Bacillus cereus internalin and other candidate virulence genes specifically induced during oral infection in insects. Mol Microbiol62:339–355
    [Google Scholar]
  17. Garsin D. A., Sifri C. D., Mylonakis E., Qin X., Singh K. V., Murray B. E., Calderwood S. B., Ausubel F. M.. 2001; A simple model host for identifying Gram-positive virulence factors. Proc Natl Acad Sci U S A98:10892–10897
    [Google Scholar]
  18. Grant S. G., Jessee J., Bloom F. R., Hanahan D.. 1990; Differential plasmid rescue from transgenic mouse DNAs into Escherichia coli methylation-restriction mutants. Proc Natl Acad Sci U S A87:4645–4649
    [Google Scholar]
  19. Hancock L. E., Gilmore M. S.. 2000; Pathogenicity of enterococci. In Gram-Positive Pathogens pp251–258 Edited by Fischetti V. A.. Washington, DC: American Society for Microbiology;
    [Google Scholar]
  20. Jha A. K., Bais H. P., Vivanco J. M.. 2005; Enterococcus faecalis mammalian virulence-related factors exhibit potent pathogenicity in the Arabidopsis thaliana plant model. Infect Immun73:464–475
    [Google Scholar]
  21. Kayaoglu G., Orstavik D.. 2004; Virulence factors of Enterococcus faecalis: relationship to endodontic disease. Crit Rev Oral Biol Med15:308–320
    [Google Scholar]
  22. Law J., Buist G., Haandrikman A., Kok J., Venema G., Leenhouts K.. 1995; A system to generate chromosomal mutations in Lactococcus lactis which allows fast analysis of targeted genes. J Bacteriol177:7011–7018
    [Google Scholar]
  23. Lepage E., Brinster S., Caron C., Ducroix-Crepy C., Rigottier-Gois L., Dunny G., Hennequet-Antier C., Serror P.. 2006; Comparative genomic hybridization analysis of Enterococcus faecalis: identification of genes absent from food strains. J Bacteriol188:6858–6868
    [Google Scholar]
  24. Lester C. H., Frimodt-Moller N., Sorensen T. L., Monnet D. L., Hammerum A. M.. 2006; In vivo transfer of the vanA resistance gene from an Enterococcus faecium isolate of animal origin to an E. faecium isolate of human origin in the intestines of human volunteers. Antimicrob Agents Chemother50:596–599
    [Google Scholar]
  25. Lopes M. de F. S., Simoes A. P., Tenreiro R., Marques J. J. F., Crespo M. T. B.. 2006; Activity and expression of a virulence factor, gelatinase, in dairy enterococci. Int J Food Microbiol112:208–214
    [Google Scholar]
  26. Maadani A., Fox K. A., Mylonakis E., Garsin D. A.. 2007; Enterococcus faecalis mutations affecting virulence in the Caenorhabditis elegans model host. Infect Immun75:2634–2637
    [Google Scholar]
  27. Maguin E., Prevost H., Ehrlich S. D., Gruss A.. 1996; Efficient insertional mutagenesis in lactococci and other Gram-positive bacteria. J Bacteriol178:931–935
    [Google Scholar]
  28. Mater D. D., Langella P., Corthier G., Flores M. J.. 2005; Evidence of vancomycin resistance gene transfer between enterococci of human origin in the gut of mice harbouring human microbiota. J Antimicrob Chemother56:975–978
    [Google Scholar]
  29. Mohamed J. A., Murray B. E.. 2006; Influence of the fsr locus on biofilm formation by Enterococcus faecalis lacking gelE. J Med Microbiol55:1747–1750
    [Google Scholar]
  30. Mundt J. O.. 1986; Enterococci. In Bergey's Manual of Systematic Bacteriology vol. 2 p1063 Edited by Sneath P. H. A., S N., Mair M. E. Sharpe., Holt J. G.. Baltimore: Williams and Wilkins;
    [Google Scholar]
  31. Mylonakis E., Moreno R., El Khoury J. B., Idnurm A., Heitman J., Calderwood S. B., Ausubel F. M., Diener A.. 2005; Galleria mellonella as a model system to study Cryptococcus neoformans pathogenesis. Infect Immun73:3842–3850
    [Google Scholar]
  32. Nakayama J., Chen S., Oyama N., Nishiguchi K., Azab E. A., Tanaka E., Kariyama R., Sonomoto K.. 2006; Revised model for Enterococcus faecalis fsr quorum-sensing system: the small open reading frame fsrD encodes the gelatinase biosynthesis-activating pheromone propeptide corresponding to staphylococcal agrD. J Bacteriol188:8321–8326
    [Google Scholar]
  33. Ogier J. C., Serror P.. 2008; Safety assessment of dairy microorganisms: the Enterococcus genus. Int J Food Microbiol126:291–301
    [Google Scholar]
  34. Park S. Y., Kim K. M., Lee J. H., Seo S. J., Lee I. H.. 2007; Extracellular gelatinase of Enterococcus faecalis destroys a defense system in insect hemolymph and human serum. Infect Immun75:1861–1869
    [Google Scholar]
  35. Qin X., Singh K. V., Weinstock G. M., Murray B. E.. 2000; Effects of Enterococcus faecalis fsr genes on production of gelatinase and a serine protease and virulence. Infect Immun68:2579–2586
    [Google Scholar]
  36. Qin X., Singh K. V., Weinstock G. M., Murray B. E.. 2001; Characterization of fsr, a regulator controlling expression of gelatinase and serine protease in Enterococcus faecalis OG1RF. J Bacteriol183:3372–3382
    [Google Scholar]
  37. Ribeiro T., Abrantes M., Lopes M. de F. S., Crespo M. T. B.. 2007; Vancomycin-susceptible dairy and clinical enterococcal isolates carry vanA and vanB genes. Int J Food Microbiol113:289–295
    [Google Scholar]
  38. Salamitou S., Ramisse F., Brehelin M., Bourguet D., Gilois N., Gominet M., Hernandez E., Lereclus D.. 2000; The PlcR regulon is involved in the opportunistic properties of Bacillus thuringiensis and Bacillus cereus in mice and insects. Microbiology146:2825–2832
    [Google Scholar]
  39. Sambrook J., Fritsch E. F., Maniatis T.. 1989; Molecular Cloning: a Laboratory Manual , 2nd edn. Cold Spring Harbor, NY: Cold Spring Harbor Laboratory;
    [Google Scholar]
  40. Schell M. A., Lipscomb L., Deshazer D.. 2008; Comparative genomics and an insect model rapidly identify novel virulence genes of Burkholderia mallei. J Bacteriol190:2306–2313
    [Google Scholar]
  41. Schneider D. S., Ayres J. S., Brandt S. M., Costa A., Dionne M. S., Gordon M. D., Mabery E. M., Moule M. G., Pham L. N.. other authors 2007; Drosophila eiger mutants are sensitive to extracellular pathogens. PLoS Pathog3:e41
    [Google Scholar]
  42. Semedo T., Santos M. A., Lopes M. F., Figueiredo Marques J. J., Barreto Crespo M. T., Tenreiro R.. 2003; Virulence factors in food, clinical and reference enterococci: a common trait in the genus?. Syst Appl Microbiol26:13–22
    [Google Scholar]
  43. Sifri C. D., Mylonakis E., Singh K. V., Qin X., Garsin D. A., Murray B. E., Ausubel F. M., Calderwood S. B.. 2002; Virulence effect of Enterococcus faecalis protease genes and the quorum-sensing locus fsr in Caenorhabditis elegans and mice. Infect Immun70:5647–5650
    [Google Scholar]
  44. Singh K. V., Nallapareddy S. R., Nannini E. C., Murray B. E.. 2005; Fsr-independent production of protease(s) may explain the lack of attenuation of an Enterococcus faecalis fsr mutant versus a gelE- sprE mutant in induction of endocarditis. Infect Immun73:4888–4894
    [Google Scholar]
  45. Tannock G. W., Cook G.. 2002; Enterococci as members of the intestinal microflora of humans. In The Enterococci: Pathogenesis, Molecular Biology and Antibiotic Resistance pp101–131 Edited by Gilmore M. S. Washington, DC: American Society for Microbiology;
    [Google Scholar]
  46. Vallet-Gely I., Lemaitre B., Boccard F.. 2008; Bacterial strategies to overcome insect defences. Nat Rev Microbiol6:302–313
    [Google Scholar]
  47. Xu J., Olson M. E., Kahn M. L., Hurlbert R. E.. 1991; Characterization of Tn 5-induced mutants of Xenorhabdus nematophilus ATCC 19061. Appl Environ Microbiol57:1173–1180
    [Google Scholar]
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