title: Lactobacillus iners: Friend or Foe?
abstract: The vaginal microbial community is typically characterized by abundant lactobacilli. Lactobacillus iners, a fairly recently detected species, is frequently present in the vaginal niche. However, the role of this species in vaginal health is unclear, since it can be detected in normal conditions as well as during vaginal dysbiosis, such as bacterial vaginosis, a condition characterized by an abnormal increase in bacterial diversity and lack of typical lactobacilli. Compared to other Lactobacillus species, L. iners has more complex nutritional requirements and a Gram-variable morphology. L. iners has an unusually small genome (ca. 1 Mbp), indicative of a symbiotic or parasitic lifestyle, in contrast to other lactobacilli that show niche flexibility and genomes of up to 3-4 Mbp. The presence of specific L. iners genes, such as those encoding iron-sulfur proteins and unique σ-factors, reflects a high degree of niche specification. The genome of L. iners strains also encodes inerolysin, a pore-forming toxin related to vaginolysin of Gardnerella vaginalis. Possibly, this organism may have clonal variants that in some cases promote a healthy vagina, and in other cases are associated with dysbiosis and disease. Future research should examine this friend or foe relationship with the host.
authors.affiliation: KU Leuven, Centre of Microbial and Plant Genetics, Kasteelpark Arenberg 20, box 2460, B- 3001 Leuven, Belgium; University of Antwerp, Department of Bioscience Engineering, Groenenborgerlaan 171, B-2020 Antwerp, Belgium.
authors.forename: Mariya I
authors.initials: MI
authors.lastname: Petrova
authors.affiliation: Western University Departments of Microbiology & Immunology and Surgery, and The Lawson Health Research Institute London, 268 Grosvenor Street, London, ON Canada N6A 4V2.
authors.forename: Gregor
authors.initials: G
authors.lastname: Reid
authors.affiliation: Ghent University, Laboratory of Bacteriology Research, Faculty of Medicine & Health Sciences, De Pintelaan 185, Medical Research Building 2, B-9000 Gent, Belgium.
authors.forename: Mario
authors.initials: M
authors.lastname: Vaneechoutte
authors.affiliation: KU Leuven, Centre of Microbial and Plant Genetics, Kasteelpark Arenberg 20, box 2460, B- 3001 Leuven, Belgium; University of Antwerp, Department of Bioscience Engineering, Groenenborgerlaan 171, B-2020 Antwerp, Belgium. Electronic address: sarah.lebeer@uantwerpen.be.
authors.forename: Sarah
authors.initials: S
authors.lastname: Lebeer
mesh_terms: D001427:Bacterial Toxins / Q000235:genetics* / Q000378:metabolism; D018441:Biofilms / Q000254:growth & development; D064112:Clustered Regularly Interspaced Short Palindromic Repeats / Q000235:genetics; D064806:Dysbiosis / Q000382:microbiology; D005260:Female; D016680:Genome, Bacterial / Q000235:genetics; D006801:Humans; D007778:Lactobacillus / Q000145:classification* / Q000235:genetics / Q000378:metabolism*; D064307:Microbiota / Q000235:genetics; D014621:Vagina / Q000382:microbiology*; D016585:Vaginosis, Bacterial / Q000382:microbiology*
chemical_list: D001427:Bacterial Toxins
keywords: bacterial vaginosis; lactobacilli; vaginal microbiota