The Experts below are selected from a list of 2490 Experts worldwide ranked by ideXlab platform
Sharon L Hillier - One of the best experts on this subject based on the ideXlab platform.
-
distribution of genital Lactobacillus strains shared by female sex partners
The Journal of Infectious Diseases, 2009Co-Authors: May Antonio, Kathy J Agnew, Sharon L HillierAbstract:The flora of the healthy vagina is dominated byH2O2-producing Lactobacillus species, predominantly Lactobacillus crispatus and Lactobacillus jensenii [1]. Bacterial vaginosis (BV) is characterized by overgrowth of commensal anaerobic flora relative to lactobacilli. BV among heterosexual women is associated with a new male sex partner and unprotected intercourse [2, 3] and with vaginal intercourse immediately after anal intercourse [4]. The prevalence of BV among lesbians is high relative to that among heterosexual women [5, 6], and BV is frequently found in both members of lesbian couples [5]. Sexual practices involving digital-vaginal or digital-anal contact might transmit vaginal fluid and may promote abnormal vaginal flora [7]. Criswell et al. [8] “transmitted” BV from one woman to another by transferring vaginal secretions. We hypothesized that sexual behaviors that could transfer vaginal fluid might also transmit lactobacilli between female sex partners. Repetitive element sequence– based PCR (rep-PCR), a DNA fingerprinting technique, has been successful in distinguishing a probiotic Lactobacillus crispatus strain from other L. crispatus strains and from other endogenous Lactobacillus species [9]. Rep-PCR uses repetitive sequences throughout the genome for direct amplification of genomic DNA, generating fingerprint patterns unique to bacterial species or strains [10]. We defined species-specific distribution of genital Lactobacillus isolates recovered from women who reported having had sex with other women and used rep-PCR fingerprinting to assess whether unique Lactobacillus strains were shared by female sex partners.
-
women s satisfaction with an intravaginal Lactobacillus capsule for the treatment of bacterial vaginosis
Journal of Womens Health, 2006Co-Authors: Jeanne M Marrazzo, Robert L Cook, Harold C Wiesenfeld, Pamela J Murray, Barbara Busse, Marijane A Krohn, Sharon L HillierAbstract:Objective: To assess women's satisfaction with a vaginal capsule containing human-derived, H2O2-producing Lactobacillus crispatus at completion of a randomized, placebo-controlled study for treatme...
-
colonization of the rectum by Lactobacillus species and decreased risk of bacterial vaginosis
The Journal of Infectious Diseases, 2005Co-Authors: May A D Antonio, Lorna K Rabe, Sharon L HillierAbstract:Lactobacilli colonizing the rectum may be a reservoir for vaginal lactobacilli. In a cross-sectional study of 531 females, vaginal and rectal colonization by lactobacilli were assessed by culture methods. A subset of isolates was identified to the species level by use of whole-chromosomal DNA probes. Lactobacillus crispatus (16%), L. jensenii (10%), and L. gasseri (10%) were the prevalent lactobacilli colonizing the rectums of 290 females. Only 13 (9%) of 147 females colonized by L. crispatus or L. jensenii vaginally and/or rectally had bacterial vaginosis (BV), compared with 12 (44%) of 27 females colonized by other H(2)O(2)-producing lactobacilli (P < .001). Cocolonization of the vagina and rectum by H(2)O(2)-producing lactobacilli was associated with the lowest prevalence of BV (5%), whereas females colonized only vaginally, only rectally, or at neither site had a successively increased risk of BV (P < .001). Lactobacillus species in the rectum may contribute to the maintenance of vaginal microflora.
-
dna fingerprinting of Lactobacillus crispatus strain ctv 05 by repetitive element sequence based pcr analysis in a pilot study of vaginal colonization
Journal of Clinical Microbiology, 2003Co-Authors: May A D Antonio, Sharon L HillierAbstract:Lactobacillus crispatus is one of the predominant hydrogen peroxide (H(2)O(2))-producing species found in the vagina and is under development as a probiotic for the treatment of bacterial vaginosis. In this study, we assessed whether DNA fingerprinting by repetitive element sequence-based PCR (rep-PCR) can be used to distinguish the capsule strain of L. crispatus (CTV-05) from other endogenous strains as well as other species of vaginal lactobacilli. Vaginal and rectal lactobacilli were identified to the species level by using whole-chromosome probe DNA hybridization. The DNAs from L. crispatus, L. jensenii, L. gasseri, and an as-yet-unnamed H(2)O(2)-negative Lactobacillus species designated 1086V were subjected to rep-PCR. The results of gel electrophoresis and ethidium bromide staining of the DNA fingerprints obtained were compared. L. crispatus CTV-05 had a unique DNA fingerprint compared to all other lactobacilli. DNA fingerprints for 27 production lots of L. crispatus sampled from 1994 through 2001 were identical to that of the original strain isolated in 1993, suggesting strain stability. In a pilot study of nine women, this DNA fingerprinting method distinguished CTV-05 from other endogenous vaginal lactobacilli prior to and after vaginal capsule use. rep-PCR DNA fingerprinting is useful for strain typing and for evaluating longitudinal loss or acquisition of vaginal lactobacilli used as probiotics.
-
dna fingerprinting of Lactobacillus crispatus strain ctv 05 by repetitive element sequence based pcr analysis in a pilot study of vaginal colonization
Journal of Clinical Microbiology, 2003Co-Authors: May A D Antonio, Sharon L HillierAbstract:Lactobacilli, the predominant group of microorganisms of the vaginal flora of healthy women, function as endogenous microbicides through the production of lactic acid, which acidifies the vagina, and hydrogen peroxide (H2O2), which reacts with myeloperoxidase to form reactive molecules toxic to human immunodeficiency virus (HIV) and other pathogens (18, 19). Bacterial vaginosis (BV), which is characterized microbiologically by the reduction or absence of lactobacilli, has been associated with an increased prevalence of HIV in several cross-sectional studies (2, 6, 17, 22, 25, 34, 35, 39) and an increased acquisition of HIV in one longitudinal study (40). Further, BV has been linked with increased viral shedding among HIV-infected women (5). In a longitudinal study, women without vaginal lactobacilli had an increased risk of HIV and gonorrhea acquisition (21), suggesting that a lack of vaginal lactobacilli may predispose women to sexually transmitted diseases, including HIV. Further, the absence of H2O2-producing lactobacilli has been associated with an increased acquisition of BV (13, 21). Lactobacillus crispatus and L. jensenii, both H2O2-producing species (1), are the predominant vaginal Lactobacillus species colonizing women without BV in Europe (11), the United States (1, 41), and Japan (38). Lactobacillus-containing probiotic products have been proposed for the treatment of vaginal infections (3, 24, 29, 30, 37). Oral administration of a probiotic containing L. rhamnosus GR-1 and L. fermentum RC-14 once or twice daily for 28 days has been correlated with healthy vaginal flora (33). However, commercially available products sold as dietary supplements do not always contain the Lactobacillus species advertised on the label and do not always contain H2O2-producing lactobacilli (15). Furthermore, compared to vaginal lactobacilli, yogurt-derived lactobacilli poorly adhere to vaginal epithelial cells in vitro (44). Studies evaluating the efficacy of some probiotic products containing lactobacilli remain inconclusive because the strain identification techniques have been inadequate, relying on classic phenotypic identification methods, such as sugar fermentation, to distinguish lactobacilli isolated before and after product use (7, 36). In one study, efficacy was revealed by comparing the clinical cure rate for BV in a group using the Lactobacillus product to that in a placebo group (12), while in another study, Nugent scoring for BV Gram staining was used to assess the outcomes for the treatment groups (32). Only one study to date has provided a DNA-based strain tracking method; in that study, random amplified polymorphic DNA-PCR analysis (8) was used to compare endogenous vaginal Lactobacillus strains to the probiotic strain. L. crispatus strain CTV-05, a vaginally derived H2O2-producing strain, is a probiotic that is being evaluated for the treatment and prevention of BV. The vehicle for the probiotic is a gelatin capsule which is inserted vaginally. The purpose of this study was to evaluate whether repetitive element sequence-based PCR (rep-PCR), a DNA fingerprinting technique, can be used to distinguish probiotic L. crispatus strain CTV-05 from other L. crispatus strains and other endogenous vaginal Lactobacillus species. rep-PCR, which makes use of repetitive sequences dispersed throughout a bacterial genome for the direct amplification of genomic DNA, generates bacterial species- or strain-specific fingerprint patterns (42).
Timo K Korhonen - One of the best experts on this subject based on the ideXlab platform.
-
identification of a high molecular mass Lactobacillus epithelium adhesin lea of Lactobacillus crispatus st1 that binds to stratified squamous epithelium
Microbiology, 2012Co-Authors: Sanna Edelman, Timo A Lehti, Veera Kainulainen, Jenni Antikainen, Riikka Kylvaja, Marc Baumann, Benita Westerlundwikstrom, Timo K KorhonenAbstract:Lactobacilli belong to the normal gastrointestinal and genital tract microbiota of human and animal hosts. Adhesion is important for bacterial colonization; however, only a few Lactobacillus adhesins have been identified so far. We studied extracted surface proteins from an adhesive Lactobacillus crispatus strain, ST1, which efficiently colonizes the chicken alimentary tract, for their binding to tissue sections of the chicken crop, and identified a novel high-molecular-mass repetitive surface protein that shows specific binding to stratified squamous epithelium. The adhesin binds to both crop epithelium and epithelial cells from human vagina, and was named Lactobacillus epithelium adhesin (LEA). Expression of LEA is strain-specific among L. crispatus strains and corresponds directly to in vitro bacterial adhesion ability. The partial sequence of the lea gene predicts that the LEA protein carries an N-terminal YSIRK signal sequence and a C-terminal LPxTG anchoring motif, as well as a highly repetitive region harbouring 82 aa long repeats with non-identical sequences that show similarity to Lactobacillus Rib/alpha-like repeats. LEA-mediated epithelial adherence may improve bacterial colonization in the chicken crop and the human vagina, which are the natural environments for L. crispatus.
-
Glutamine Synthetase and Glucose-6-Phosphate Isomerase Are Adhesive Moonlighting Proteins of Lactobacillus crispatus Released by Epithelial Cathelicidin LL-37
Journal of Bacteriology, 2012Co-Authors: Veera Kainulainen, Sanna Edelman, Jenni Antikainen, Riikka Kylvaja, Vuokko Loimaranta, Anna Maria Pekkala, Maiju Laaksonen, Liisa Laakkonen, Jukka Finne, Timo K KorhonenAbstract:Glutamine synthetase (GS) and glucose-6-phosphate isomerase (GPI) were identified as novel adhesive moonlighting proteins of Lactobacillus crispatus ST1. Both proteins were bound onto the bacterial surface at acidic pHs, whereas a suspension of the cells to pH 8 caused their release into the buffer, a pattern previously observed with surface-bound enolase and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) of L. crispatus. The pH shift was associated with a rapid and transient increase in cell wall permeability, as measured by cell staining with propidium iodide. A gradual increase in the release of the four moonlighting proteins was also observed after the treatment of L. crispatus ST1 cells with increasing concentrations of the antimicrobial cationic peptide LL-37, which kills bacteria by disturbing membrane integrity and was here observed to increase the cell wall permeability of L. crispatus ST1. At pH 4, the fusion proteins His6-GS, His6-GPI, His6-enolase, and His6-GAPDH showed localized binding to cell division septa and poles of L. crispatus ST1 cells, whereas no binding to Lactobacillus rhamnosus GG was detected. Strain ST1 showed a pH-dependent adherence to the basement membrane preparation Matrigel. Purified His6-GS and His6-GPI proteins bound to type I collagen, and His6-GS also bound to laminin, and their level of binding was higher at pH 5.5 than at pH 6.5. His6-GS also expressed a plasminogen receptor function. The results show the strain-dependent surface association of moonlighting proteins in lactobacilli and that these proteins are released from the L. crispatus surface after cell trauma, under conditions of alkaline stress, or in the presence of the antimicrobial peptide LL-37 produced by human cells.
-
enolases from gram positive bacterial pathogens and commensal lactobacilli share functional similarity in virulence associated traits
Fems Immunology and Medical Microbiology, 2007Co-Authors: Jenni Antikainen, Kaarina Lähteenmäki, Veera Kuparinen, Timo K KorhonenAbstract:Enolase occurs as a cytoplasmic and a surface-associated protein in bacteria. Enolases of the bacterial pathogens Streptococcus pyogenes, Streptococcus pneumoniae and Staphylococcus aureus, as well as of the commensal lactic acid bacteria, Lactobacillus crispatus and Lactobacillus johnsonii, were purified as His6-fusion proteins from recombinant Escherichia coli. The fusion proteins were compared for putative virulence-associated functions, i.e., binding of human plasminogen, enhancement of plasminogen activation by human plasminogen activators, as well as binding to immobilized laminin, fibronectin and collagens. The individual enolases showed varying efficiencies in these functions. In particular, highly and equally effective interactions with plasminogen and laminin were seen with lactobacillar and staphylococcal enolases.
-
ph dependent association of enolase and glyceraldehyde 3 phosphate dehydrogenase of Lactobacillus crispatus with the cell wall and lipoteichoic acids
Journal of Bacteriology, 2007Co-Authors: Jenni Antikainen, Veera Kupannen, Kaarina Lähteenmäki, Timo K KorhonenAbstract:The plasminogen-binding proteins enolase and glyceraldehyde-3-phosphate dehydrogenase of Lactobacillus crispatus were localized on the cell surface at pH 5 but released into the medium at an alkaline pH. These proteins bound to lipoteichoic acids at a pH below their isoelectric point. The results indicate that lactobacilli rapidly modify their surface properties in response to changes in pH.
-
extracellular proteins of Lactobacillus crispatus enhance activation of human plasminogen
Microbiology, 2007Co-Authors: Veera Hurmalainen, Kaarina Lähteenmäki, Sanna Edelman, Jenni Antikainen, Marc Baumann, Timo K KorhonenAbstract:The abundant proteolytic plasminogen (Plg)/plasmin system is important in several physiological functions in mammals and also engaged by a number of pathogenic microbial species to increase tissue invasiveness or to obtain nutrients. This paper reports that a commensal bacterium, Lactobacillus crispatus, interacts with the Plg system. Strain ST1 of L. crispatus enhanced activation of human Plg by the tissue-type Plg activator (tPA), whereas enhancement of the urokinase-mediated Plg activation was lower. ST1 cells bound Plg, plasmin and tPA only poorly, and the Plg-binding and activation-enhancing capacities were associated with extracellular material released from the bacteria into buffer. The extracellular proteome of L. crispatus ST1 contained enolase and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as major components. The enolase and the GAPDH genes of ST1 were cloned, sequenced and expressed in recombinant Escherichia coli as His6-fusion proteins, which bound Plg and enhanced its activation by tPA. Variable levels of secretion of enolase and GAPDH proteins as well as of the Plg activation cofactor function were detected in strains representing major taxonomic groups of the genus Lactobacillus. So far, interference with the Plg system has been addressed with pathogenic microbes. The results reported here demonstrate a novel interaction between a member of the microbiota and a major proteolytic system in humans.
Jenni Antikainen - One of the best experts on this subject based on the ideXlab platform.
-
identification of a high molecular mass Lactobacillus epithelium adhesin lea of Lactobacillus crispatus st1 that binds to stratified squamous epithelium
Microbiology, 2012Co-Authors: Sanna Edelman, Timo A Lehti, Veera Kainulainen, Jenni Antikainen, Riikka Kylvaja, Marc Baumann, Benita Westerlundwikstrom, Timo K KorhonenAbstract:Lactobacilli belong to the normal gastrointestinal and genital tract microbiota of human and animal hosts. Adhesion is important for bacterial colonization; however, only a few Lactobacillus adhesins have been identified so far. We studied extracted surface proteins from an adhesive Lactobacillus crispatus strain, ST1, which efficiently colonizes the chicken alimentary tract, for their binding to tissue sections of the chicken crop, and identified a novel high-molecular-mass repetitive surface protein that shows specific binding to stratified squamous epithelium. The adhesin binds to both crop epithelium and epithelial cells from human vagina, and was named Lactobacillus epithelium adhesin (LEA). Expression of LEA is strain-specific among L. crispatus strains and corresponds directly to in vitro bacterial adhesion ability. The partial sequence of the lea gene predicts that the LEA protein carries an N-terminal YSIRK signal sequence and a C-terminal LPxTG anchoring motif, as well as a highly repetitive region harbouring 82 aa long repeats with non-identical sequences that show similarity to Lactobacillus Rib/alpha-like repeats. LEA-mediated epithelial adherence may improve bacterial colonization in the chicken crop and the human vagina, which are the natural environments for L. crispatus.
-
Glutamine Synthetase and Glucose-6-Phosphate Isomerase Are Adhesive Moonlighting Proteins of Lactobacillus crispatus Released by Epithelial Cathelicidin LL-37
Journal of Bacteriology, 2012Co-Authors: Veera Kainulainen, Sanna Edelman, Jenni Antikainen, Riikka Kylvaja, Vuokko Loimaranta, Anna Maria Pekkala, Maiju Laaksonen, Liisa Laakkonen, Jukka Finne, Timo K KorhonenAbstract:Glutamine synthetase (GS) and glucose-6-phosphate isomerase (GPI) were identified as novel adhesive moonlighting proteins of Lactobacillus crispatus ST1. Both proteins were bound onto the bacterial surface at acidic pHs, whereas a suspension of the cells to pH 8 caused their release into the buffer, a pattern previously observed with surface-bound enolase and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) of L. crispatus. The pH shift was associated with a rapid and transient increase in cell wall permeability, as measured by cell staining with propidium iodide. A gradual increase in the release of the four moonlighting proteins was also observed after the treatment of L. crispatus ST1 cells with increasing concentrations of the antimicrobial cationic peptide LL-37, which kills bacteria by disturbing membrane integrity and was here observed to increase the cell wall permeability of L. crispatus ST1. At pH 4, the fusion proteins His6-GS, His6-GPI, His6-enolase, and His6-GAPDH showed localized binding to cell division septa and poles of L. crispatus ST1 cells, whereas no binding to Lactobacillus rhamnosus GG was detected. Strain ST1 showed a pH-dependent adherence to the basement membrane preparation Matrigel. Purified His6-GS and His6-GPI proteins bound to type I collagen, and His6-GS also bound to laminin, and their level of binding was higher at pH 5.5 than at pH 6.5. His6-GS also expressed a plasminogen receptor function. The results show the strain-dependent surface association of moonlighting proteins in lactobacilli and that these proteins are released from the L. crispatus surface after cell trauma, under conditions of alkaline stress, or in the presence of the antimicrobial peptide LL-37 produced by human cells.
-
enolases from gram positive bacterial pathogens and commensal lactobacilli share functional similarity in virulence associated traits
Fems Immunology and Medical Microbiology, 2007Co-Authors: Jenni Antikainen, Kaarina Lähteenmäki, Veera Kuparinen, Timo K KorhonenAbstract:Enolase occurs as a cytoplasmic and a surface-associated protein in bacteria. Enolases of the bacterial pathogens Streptococcus pyogenes, Streptococcus pneumoniae and Staphylococcus aureus, as well as of the commensal lactic acid bacteria, Lactobacillus crispatus and Lactobacillus johnsonii, were purified as His6-fusion proteins from recombinant Escherichia coli. The fusion proteins were compared for putative virulence-associated functions, i.e., binding of human plasminogen, enhancement of plasminogen activation by human plasminogen activators, as well as binding to immobilized laminin, fibronectin and collagens. The individual enolases showed varying efficiencies in these functions. In particular, highly and equally effective interactions with plasminogen and laminin were seen with lactobacillar and staphylococcal enolases.
-
ph dependent association of enolase and glyceraldehyde 3 phosphate dehydrogenase of Lactobacillus crispatus with the cell wall and lipoteichoic acids
Journal of Bacteriology, 2007Co-Authors: Jenni Antikainen, Veera Kupannen, Kaarina Lähteenmäki, Timo K KorhonenAbstract:The plasminogen-binding proteins enolase and glyceraldehyde-3-phosphate dehydrogenase of Lactobacillus crispatus were localized on the cell surface at pH 5 but released into the medium at an alkaline pH. These proteins bound to lipoteichoic acids at a pH below their isoelectric point. The results indicate that lactobacilli rapidly modify their surface properties in response to changes in pH.
-
extracellular proteins of Lactobacillus crispatus enhance activation of human plasminogen
Microbiology, 2007Co-Authors: Veera Hurmalainen, Kaarina Lähteenmäki, Sanna Edelman, Jenni Antikainen, Marc Baumann, Timo K KorhonenAbstract:The abundant proteolytic plasminogen (Plg)/plasmin system is important in several physiological functions in mammals and also engaged by a number of pathogenic microbial species to increase tissue invasiveness or to obtain nutrients. This paper reports that a commensal bacterium, Lactobacillus crispatus, interacts with the Plg system. Strain ST1 of L. crispatus enhanced activation of human Plg by the tissue-type Plg activator (tPA), whereas enhancement of the urokinase-mediated Plg activation was lower. ST1 cells bound Plg, plasmin and tPA only poorly, and the Plg-binding and activation-enhancing capacities were associated with extracellular material released from the bacteria into buffer. The extracellular proteome of L. crispatus ST1 contained enolase and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as major components. The enolase and the GAPDH genes of ST1 were cloned, sequenced and expressed in recombinant Escherichia coli as His6-fusion proteins, which bound Plg and enhanced its activation by tPA. Variable levels of secretion of enolase and GAPDH proteins as well as of the Plg activation cofactor function were detected in strains representing major taxonomic groups of the genus Lactobacillus. So far, interference with the Plg system has been addressed with pathogenic microbes. The results reported here demonstrate a novel interaction between a member of the microbiota and a major proteolytic system in humans.
May A D Antonio - One of the best experts on this subject based on the ideXlab platform.
-
colonization of the rectum by Lactobacillus species and decreased risk of bacterial vaginosis
The Journal of Infectious Diseases, 2005Co-Authors: May A D Antonio, Lorna K Rabe, Sharon L HillierAbstract:Lactobacilli colonizing the rectum may be a reservoir for vaginal lactobacilli. In a cross-sectional study of 531 females, vaginal and rectal colonization by lactobacilli were assessed by culture methods. A subset of isolates was identified to the species level by use of whole-chromosomal DNA probes. Lactobacillus crispatus (16%), L. jensenii (10%), and L. gasseri (10%) were the prevalent lactobacilli colonizing the rectums of 290 females. Only 13 (9%) of 147 females colonized by L. crispatus or L. jensenii vaginally and/or rectally had bacterial vaginosis (BV), compared with 12 (44%) of 27 females colonized by other H(2)O(2)-producing lactobacilli (P < .001). Cocolonization of the vagina and rectum by H(2)O(2)-producing lactobacilli was associated with the lowest prevalence of BV (5%), whereas females colonized only vaginally, only rectally, or at neither site had a successively increased risk of BV (P < .001). Lactobacillus species in the rectum may contribute to the maintenance of vaginal microflora.
-
dna fingerprinting of Lactobacillus crispatus strain ctv 05 by repetitive element sequence based pcr analysis in a pilot study of vaginal colonization
Journal of Clinical Microbiology, 2003Co-Authors: May A D Antonio, Sharon L HillierAbstract:Lactobacillus crispatus is one of the predominant hydrogen peroxide (H(2)O(2))-producing species found in the vagina and is under development as a probiotic for the treatment of bacterial vaginosis. In this study, we assessed whether DNA fingerprinting by repetitive element sequence-based PCR (rep-PCR) can be used to distinguish the capsule strain of L. crispatus (CTV-05) from other endogenous strains as well as other species of vaginal lactobacilli. Vaginal and rectal lactobacilli were identified to the species level by using whole-chromosome probe DNA hybridization. The DNAs from L. crispatus, L. jensenii, L. gasseri, and an as-yet-unnamed H(2)O(2)-negative Lactobacillus species designated 1086V were subjected to rep-PCR. The results of gel electrophoresis and ethidium bromide staining of the DNA fingerprints obtained were compared. L. crispatus CTV-05 had a unique DNA fingerprint compared to all other lactobacilli. DNA fingerprints for 27 production lots of L. crispatus sampled from 1994 through 2001 were identical to that of the original strain isolated in 1993, suggesting strain stability. In a pilot study of nine women, this DNA fingerprinting method distinguished CTV-05 from other endogenous vaginal lactobacilli prior to and after vaginal capsule use. rep-PCR DNA fingerprinting is useful for strain typing and for evaluating longitudinal loss or acquisition of vaginal lactobacilli used as probiotics.
-
dna fingerprinting of Lactobacillus crispatus strain ctv 05 by repetitive element sequence based pcr analysis in a pilot study of vaginal colonization
Journal of Clinical Microbiology, 2003Co-Authors: May A D Antonio, Sharon L HillierAbstract:Lactobacilli, the predominant group of microorganisms of the vaginal flora of healthy women, function as endogenous microbicides through the production of lactic acid, which acidifies the vagina, and hydrogen peroxide (H2O2), which reacts with myeloperoxidase to form reactive molecules toxic to human immunodeficiency virus (HIV) and other pathogens (18, 19). Bacterial vaginosis (BV), which is characterized microbiologically by the reduction or absence of lactobacilli, has been associated with an increased prevalence of HIV in several cross-sectional studies (2, 6, 17, 22, 25, 34, 35, 39) and an increased acquisition of HIV in one longitudinal study (40). Further, BV has been linked with increased viral shedding among HIV-infected women (5). In a longitudinal study, women without vaginal lactobacilli had an increased risk of HIV and gonorrhea acquisition (21), suggesting that a lack of vaginal lactobacilli may predispose women to sexually transmitted diseases, including HIV. Further, the absence of H2O2-producing lactobacilli has been associated with an increased acquisition of BV (13, 21). Lactobacillus crispatus and L. jensenii, both H2O2-producing species (1), are the predominant vaginal Lactobacillus species colonizing women without BV in Europe (11), the United States (1, 41), and Japan (38). Lactobacillus-containing probiotic products have been proposed for the treatment of vaginal infections (3, 24, 29, 30, 37). Oral administration of a probiotic containing L. rhamnosus GR-1 and L. fermentum RC-14 once or twice daily for 28 days has been correlated with healthy vaginal flora (33). However, commercially available products sold as dietary supplements do not always contain the Lactobacillus species advertised on the label and do not always contain H2O2-producing lactobacilli (15). Furthermore, compared to vaginal lactobacilli, yogurt-derived lactobacilli poorly adhere to vaginal epithelial cells in vitro (44). Studies evaluating the efficacy of some probiotic products containing lactobacilli remain inconclusive because the strain identification techniques have been inadequate, relying on classic phenotypic identification methods, such as sugar fermentation, to distinguish lactobacilli isolated before and after product use (7, 36). In one study, efficacy was revealed by comparing the clinical cure rate for BV in a group using the Lactobacillus product to that in a placebo group (12), while in another study, Nugent scoring for BV Gram staining was used to assess the outcomes for the treatment groups (32). Only one study to date has provided a DNA-based strain tracking method; in that study, random amplified polymorphic DNA-PCR analysis (8) was used to compare endogenous vaginal Lactobacillus strains to the probiotic strain. L. crispatus strain CTV-05, a vaginally derived H2O2-producing strain, is a probiotic that is being evaluated for the treatment and prevention of BV. The vehicle for the probiotic is a gelatin capsule which is inserted vaginally. The purpose of this study was to evaluate whether repetitive element sequence-based PCR (rep-PCR), a DNA fingerprinting technique, can be used to distinguish probiotic L. crispatus strain CTV-05 from other L. crispatus strains and other endogenous vaginal Lactobacillus species. rep-PCR, which makes use of repetitive sequences dispersed throughout a bacterial genome for the direct amplification of genomic DNA, generates bacterial species- or strain-specific fingerprint patterns (42).
Susan Holmes - One of the best experts on this subject based on the ideXlab platform.
-
dada2 high resolution sample inference from illumina amplicon data
Nature Methods, 2016Co-Authors: Benjamin J Callahan, Paul J Mcmurdie, Michael J Rosen, Andrew W Han, Amy Jo A Johnson, Susan HolmesAbstract:We present the open-source software package DADA2 for modeling and correcting Illumina-sequenced amplicon errors (https://github.com/benjjneb/dada2). DADA2 infers sample sequences exactly and resolves differences of as little as 1 nucleotide. In several mock communities, DADA2 identified more real variants and output fewer spurious sequences than other methods. We applied DADA2 to vaginal samples from a cohort of pregnant women, revealing a diversity of previously undetected Lactobacillus crispatus variants.
-
dada2 high resolution sample inference from amplicon data
bioRxiv, 2015Co-Authors: Benjamin J Callahan, Paul J Mcmurdie, Michael J Rosen, Andrew W Han, Amy Jo A Johnson, Susan HolmesAbstract:Microbial communities are commonly characterized by amplifying and sequencing target genes, but errors limit the precision of amplicon sequencing. We present DADA2, a software package that models and corrects amplicon errors. DADA2 identified more real variants than other methods in Illumina-sequenced mock communities, some differing by a single nucleotide, while outputting fewer spurious sequences. DADA2 analysis of vaginal samples revealed a diversity of Lactobacillus crispatus strains undetected by OTU methods.
