Bacteriophage induction versus vaginal homeostasis: role of H2O2 in the selection of Lactobacillus defective prophages Authors Rebeca Martín Microbiology Area, University Institute of Biotechnology, University of Oviedo, Oviedo, Spain Nora Soberón Microbiology Area, University Institute of Biotechnology, University of Oviedo, Oviedo, Spain Susana Escobedo Microbiology Area, University Institute of Biotechnology, University of Oviedo, Oviedo, Spain Juan E. Suárez Microbiology Area, University Institute of Biotechnology, University of Oviedo, Oviedo, Spain Institute of Dairy Products of Asturias (CSIC), Villaviciosa, Spain Keywords: Lactobacillus, bacteriophages of Lactobacillus, prophages, vaginal microbiota, SOS response Abstract Vaginal disorders associated with systemic chemotherapy arise by direct inhibition of the resident microbiota (dominated by lactobacilli) or, possibly, by induction of prophages harbored in their genomes, leading to cell lysis. In the present study, proficient Lactobacillus phages could not be isolated from vaginal exudates. However, lysogeny appeared to be widespread, although about half of the strains harbored prophage sequences that were not responsive to SOS activation. In other cases, prophage induction was achieved, but viable phages were not generated, despite the fact that the induced supernatants of some strains were bactericidal. In one case, this activity was accompanied by the production of a bacteriophage subsequently identified as a member of the family Siphoviridae (isometric capsid and long non-contractile tail). Most of the lactobacilli tested generated hydrogen peroxide, which acted as an inducer of the SOS response, suggesting that H2O2 selects for strains that harbor SOS-insensitive, defective prophages, which are thus unable to promote vaginal lactobacilli phageinduced lysis. [Int Microbiol 2009; 12(2):131-136] Author Biographies Rebeca Martín, Microbiology Area, University Institute of Biotechnology, University of Oviedo, Oviedo, Spain Microbiology Area, University Institute of Biotechnology, University of Oviedo, Oviedo, Spain Nora Soberón, Microbiology Area, University Institute of Biotechnology, University of Oviedo, Oviedo, Spain Microbiology Area, University Institute of Biotechnology, University of Oviedo, Oviedo, Spain Susana Escobedo, Microbiology Area, University Institute of Biotechnology, University of Oviedo, Oviedo, Spain Microbiology Area, University Institute of Biotechnology, University of Oviedo, Oviedo, Spain Juan E. Suárez, Microbiology Area, University Institute of Biotechnology, University of Oviedo, Oviedo, Spain Institute of Dairy Products of Asturias (CSIC), Villaviciosa, Spain Microbiology Area, University Institute of Biotechnology, University of Oviedo, Oviedo, Spain Institute of Dairy Products of Asturias (CSIC), Villaviciosa, Spain Downloads PDF Published 2010-01-13 Issue Vol. 12 No. 2 (2009) Section Research Articles License Submission of a manuscript to International Microbiology implies: that the work described has not been published before, including publication in the World Wide Web (except in the form of an Abstract or as part of a published lecture, review, or thesis); that it is not under consideration for publication elsewhere; that all the coauthors have agreed to its publication. The corresponding author signs for and accepts responsability for releasing this material and will act on behalf of any and all coauthors regarding the editorial review and publication process.If an article is accepted for publication in International Microbiology, the authors (or other copyright holder) must transfer to the journal the right–not exclusive–to reproduce and distribute the article including reprints, translations, photographic reproductions, microform, electronic form (offline, online) or any other reproductions of similar nature. Nevertheless, all article in International Microbiology will be available on the Internet to any reader at no cost. The journal allows users to freely download, copy, print, distribute, search, and link to the full text of any article, provided the authorship and source of the published article is cited. The copyright owner's consent does not include copying for new works, or resale. In these cases, the specific written permission of International Microbiology must first be obtained.Authors are requested to create a link to the published article on the journal's website. The link must be accompanied by the following text: "The original publication is available on LINK at <http://www.im.microbios.org>. Please use the appropiate URL for the article in LINK. Articles disseminated via LINK are indexed, abstracted, and referenced by many abstracting and information services, bibliographic networks, subscription agencies, library networks, and consortia.
