Quantitative determination by real-time PCR of four vaginal Lactobacillus species, Gardnerella vaginalis and Atopobium vaginae indicates an inverse relationship between L. gasseri and L. iners

Backer, E. De; Verhelst, Rita; Verstraelen, Hans; Alqumber, Mohammed A.; Burton, Jeremy P.; Tagg, John; Temmerman, Marleen; Vaneechoutte, Mario

doi:10.1186/1471-2180-7-115

Cited by 171 publications

(136 citation statements)

References 52 publications

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“…A more recent study conducted in Kenya (Matu et al, 2009) found L. jensenii to be the most abundant species using culture and phenotypic identification methods. In Belgian women, L. iners is more dominant in altered vaginal microflora (De Backer et al, 2007). One group (Anukam et al, 2005;Anukam et al, 2006) did not however detect lactobacilli in BV cases whereas in the current study, of the nine Lactobacillus species detected, eight of them were present in the non-grade I samples.…”

Section: Discussioncontrasting

confidence: 52%

Characterisation of the vaginal microflora of human immunodeficiency virus (HIV) positive and negative women in a sub-urban population of Kenya

Kiama¹,

Verhelst²,

Mbugua³

et al. 2014

Afr. J. Biotechnol.

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Section: Discussioncontrasting

confidence: 52%

Characterisation of the vaginal microflora of human immunodeficiency virus (HIV) positive and negative women in a sub-urban population of Kenya

Kiama¹,

Verhelst²,

Mbugua³

et al. 2014

Afr. J. Biotechnol.

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“…These organisms are thought to play a role in resistance of the vaginal tract to colonization by pathogens, possibly through the production of lactic acid. L. iners is unusual among lactobacilli in that it may be detected during bacterial vaginosis (BV), a state in which G. vaginalis generally predominates and other Lactobacillus species are only rarely found at the vaginal mucosal surface (7,11,40,41). More recently, culture-independent studies of the vaginal microbiota have demonstrated that L. iners vaginal colonization may be considerably more prevalent than previously recognized, and in some cases it may be the most abundant organism detected (29,36).…”

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confidence: 87%

Inerolysin, a Cholesterol-Dependent Cytolysin Produced by Lactobacillus iners

et al. 2011

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Lactobacillus iners is a common constituent of the human vaginal microbiota. This species was only recently characterized due to its fastidious growth requirements and has been hypothesized to play a role in the pathogenesis of bacterial vaginosis. Here we present the identification and molecular characterization of a protein toxin produced by L. iners. The L. iners genome encodes an open reading frame with significant primary sequence similarity to intermedilysin (ILY; 69.2% similarity) and vaginolysin (VLY; 68.4% similarity), the cholesterol-dependent cytolysins from Streptococcus intermedius and Gardnerella vaginalis, respectively. Clinical isolates of L. iners produce this protein, inerolysin (INY), during growth in vitro, as assessed by Western analysis. INY is a pore-forming toxin that is activated by reducing agents and inhibited by excess cholesterol. It is active across a pH range of 4.5 to 6.0 but is inactive at pH 7.4. At sublytic concentrations, INY activates p38 mitogen-activated protein kinase and allows entry of fluorescent phalloidin into the cytoplasm of epithelial cells. Unlike VLY and ILY, which are human specific, INY is active against cells from a broad range of species. INY represents a new target for studies directed at understanding the role of L. iners in states of health and disease at the vaginal mucosal surface.The cholesterol-dependent cytolysins (CDCs) are a family of protein toxins produced by a wide range of Gram-positive bacteria. CDCs share several characteristics, including a fourdomain structure, a requirement for membrane cholesterol for efficient activity, and an ability to form large pores in host cells, exceeding 150 Å in diameter (38). In general, soluble CDC monomers are secreted into the extracellular environment and bind to target cell membranes through direct recognition of cholesterol or, in the cases of the human-specific toxins vaginolysin (VLY) from Gardnerella vaginalis and intermedilysin (ILY) from Streptococcus intermedius, via recognition of human CD59 on the target cell surface (12,14,21). Following membrane association, CDCs oligomerize to form a prepore structure, a process that is dependent upon the availability of cholesterol (22)(23)(24)34). In many cases, CDCs are required for virulence for their cognate organisms, and rather than acting solely as cytolytic toxins, CDCs may have more sophisticated roles in disease pathogenesis (15,18,30). Understanding CDC evolution and host specificity is of considerable interest and has been limited by incomplete knowledge of the diversity of the CDC family. In particular, characterization of cytolysins most closely related to those in which host specificity has evolved may provide additional insights into the mechanism and effects of such restriction.Lactobacillus iners is a relatively recently recognized member of the human vaginal microbiota (9, 33, 42) that was initially overlooked because of its inability to grow on de ManRogosa-Sharpe agar, which is normally used to isolate vaginal lactobacilli. In healthy women...

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“…Furthermore, the relative proportions of community types differed among women of different ethnicities (1). The same four species have been reported to dominate the vaginal communities of healthy women across the world (2)(3)(4)(5)(6)(7)(8)(9). Even though the four Lactobacillus species commonly found and abundant in the human vagina have been isolated from other sites, their occurrence is extremely rare (10)(11)(12)(13)(14).…”

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confidence: 99%

Comparative Functional Genomics of Lactobacillus spp. Reveals Possible Mechanisms for Specialization of Vaginal Lactobacilli to Their Environment

et al. 2014

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dLactobacilli are found in a wide variety of habitats. Four species, Lactobacillus crispatus, L. gasseri, L. iners, and L. jensenii, are common and abundant in the human vagina and absent from other habitats. These may be adapted to the vagina and possess characteristics enabling them to thrive in that environment. Furthermore, stable codominance of multiple Lactobacillus species in a single community is infrequently observed. Thus, it is possible that individual vaginal Lactobacillus species possess unique characteristics that confer to them host-specific competitive advantages. We performed comparative functional genomic analyses of representatives of 25 species of Lactobacillus, searching for habitat-specific traits in the genomes of the vaginal lactobacilli. We found that the genomes of the vaginal species were significantly smaller and had significantly lower GC content than those of the nonvaginal species. No protein families were found to be specific to the vaginal species analyzed, but some were either overor underrepresented relative to nonvaginal species. We also found that within the vaginal species, each genome coded for species-specific protein families. Our results suggest that even though the vaginal species show no general signatures of adaptation to the vaginal environment, each species has specific and perhaps unique ways of interacting with its environment, be it the host or other microbes in the community. These findings will serve as a foundation for further exploring the role of lactobacilli in the ecological dynamics of vaginal microbial communities and their ultimate impact on host health.

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Quantitative determination by real-time PCR of four vaginal Lactobacillus species, Gardnerella vaginalis and Atopobium vaginae indicates an inverse relationship between L. gasseri and L. iners

Cited by 171 publications

References 52 publications

Characterisation of the vaginal microflora of human immunodeficiency virus (HIV) positive and negative women in a sub-urban population of Kenya

Characterisation of the vaginal microflora of human immunodeficiency virus (HIV) positive and negative women in a sub-urban population of Kenya

Inerolysin, a Cholesterol-Dependent Cytolysin Produced by Lactobacillus iners

Comparative Functional Genomics of Lactobacillus spp. Reveals Possible Mechanisms for Specialization of Vaginal Lactobacilli to Their Environment

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