H2O2-producing Lactobacilli Research Articles

Vaginal Ozone Insufflation in Management of Vaginal Candidiasis

The vagina of a woman is a sophisticated microecology system. Typically, the H2O2-producing Lactobacillus dominates the vaginal microbiota of healthy women. This bacterium converts glycogen in vaginal epithelial cells into lactic acid, sustaining the vagina's natural acidic environment. Understanding the substantial correlation between the vaginal and upper genital tract microbiota and vaginal and genital tract infections has led to an interest in these areas. However, the spectrum of microbial types consistent with a functioning genital tract and the variables influencing the flora remains perplexing. The most prevalent gynecological condition seen in primary care, vaginitis caused by Candida albicans, is a significant public health concern due to its high frequency. Candidal vulvovaginitis, also known as vaginal thrush and vaginal yeast infection, is an overgrowth of yeast in the vagina that irritates. Ozone treatment has made its way into German medical practice, where it is successfully applied to treat several disorders. Medical ozone's qualities, such as its bactericidal, virucidal, fungicidal, analgesic, and other effects, have been utilized in therapy, surgery, obstetrics and gynecology, dermatology, stomatology, and the treatment of infectious and venereal illnesses. During ozone treatment or therapy, a catheter was used to insufflate an ozone/oxygen gas mixture into the female reproductive system. They were completed continuously by attaching a catheter to the ozone output hose and allowing the ozone/oxygen gas mix to flow for the allotted time. Based on clinical and microbiological evidence, the effectiveness standards Complete clinical and microbiological recovery observable clinical symptoms that are objective. The vaginal mucous membrane was free of inflammatory disorders following treatment, and vaginal cultures were negative.

Distinct Functional Traits of Lactobacilli from Women with Asymptomatic Bacterial Vaginosis and Normal Microbiota.

Asymptomatic bacterial vaginosis (BV) in reproductive-age women has serious obstetric and gynecological consequences. Despite its high incidence, the behavior of vaginal lactobacilli in asymptomatic BV is unknown. We analyzed the functional properties of previously isolated vaginal lactobacilli from asymptomatic women with normal, intermediate, and BV microbiota. Lactic acid and antimicrobial activity against seven urogenital pathogens were evaluated from lactobacilli cell-free culture supernatants (CFCs) (n = 207) after 48 h incubation in MRS. Lactobacilli isolates were used to evaluate H2O2, autoaggregation and coaggregation with C. albicans. Lactobacilli from normal microbiota produced more d-lactate than lactobacilli from intermediate and asymptomatic BV (p = 0.007). L. plantarum, L. fermentum and L. reuteri produced greater d-lactate whereas L. rhamnosus, L. crispatus, L. johnsonii were greater producers of l-lactate. Interspecies positive correlation was observed in the lactic acid contents of CFCs. Distribution of H2O2-producing lactobacilli did not vary significantly among the groups. When lactic acid isomers were considered, species from intermediate and BV microbiota clustered together with each other and distinctly from species of normal microbiota. Broad-spectrum antagonism (≥90% inhibition) against E. coli, C. albicans, S. aureus, P. aeruginosa, G. vaginalis, N. gonorrhoeae, S. agalactiae were displayed by 46.86% (97) of isolates. Our study highlights the differential functional properties of vaginal lactobacilli from women with normal microbiota and asymptomatic BV.

Prevalence of bacterial vaginosis in pregnant and non-pregnant Iranian women: a systematic review and meta-analysis.

Bacterial vaginosis (BV) is a vaginal disorder which occurs either symptomatic or asymptomatic because of an imbalance between H2O2-producing Lactobacillus and Gardnerella vaginalis in the vagina. This systematic review and meta-analysis is the first to determine the prevalence of BV in pregnant and non-pregnant women in Iran. We used national (SID, Irandoc, Iranmedex and Magiran) and international (PubMed, Scopus, Google Scholar and ISI web of knowledge) electronic databases to systematically search and collect available studies using related keywords (up to 1 December 2017). Inclusion and exclusion criteria were defined to select eligible studies. The overall prevalence of BV among Iranian women was 18.9% (95% CI 14-25). Gardnerella vaginalis was the most prevalent isolated bacteria. The prevalence of BV in non-pregnant women was 28% (95% CI 15.1-45.9) which was higher compared with pregnant women who had a prevalence of 16.5% (95% CI 12.5-21.6). The present review revealed a high prevalence of BV in non-pregnant women. Given that BV is associated with a series of reproductive complications such as infertility, taking preventive measures such as awareness of patients as well as monitoring and controlling of syndrome are essential.

Lactobacilli enhance reactive oxygen species-dependent apoptosis-inducing signaling

H2O2-producing lactobacilli in the vaginal fluid have been suggested to play a potential tumor-preventive role in addition to the control of undesirable microorganisms. As the vaginal fluid also contains a significant concentration of peroxidase that might utilize lactobacilli-derived H2O2 as substrate for HOCl synthesis, a dominant biological role of HOCl in both natural defence systems has been postulated.Our study shows that lactobacillus-derived H2O2 per se is not likely to be beneficial for the vaginal epithelium, as it causes apoptosis nonselectively in nontransformed as well as transformed cells. However, the combination of lactobacilli and peroxidase, i.e. the situation that is actually found in vivo, leads to the conversion of H2O2 to HOCl which does not affect non-malignant cells, as these do not generate extracellular superoxide anions. In contrast, malignant cells, due to their abundant extracellular superoxide anion generation allow the generation of apoptosis-inducing hydroxyl radicals through HOCl/superoxide anion interaction. In total, our data show that the combination of H2O2 -generating lactobacilli and peroxidase causes the selective elimination of malignant cells and thus might contribute to the tumorpreventive potential of lactobacilli. These findings are in good agreement with epidemiological data. The contribution of lactobacilli in this system can be completely mimicked by H2O2-generating glucose oxidase, indicating that it is fully explained by bacterial generation of H2O2.

Effects of combined oral contraceptives, depot medroxyprogesterone acetate and the levonorgestrel-releasing intrauterine system on the vaginal microbiome

ObjectivesPrior studies suggest that the composition of the vaginal microbiome may positively or negatively affect susceptibility to sexually transmitted infections (STIs) and bacterial vaginosis (BV). Some female hormonal contraceptive methods also appear to positively or negatively influence STI transmission and BV. Therefore, changes in the vaginal microbiome that are associated with different contraceptive methods may explain, in part, effects on STI transmission and BV. Study designWe performed a retrospective study of 16S rRNA gene survey data of vaginal samples from a subset of participants from the Human Vaginal Microbiome Project at Virginia Commonwealth University. The subset included 682 women who reported using a single form of birth control that was condoms, combined oral contraceptives (COCs), depot medroxyprogesterone acetate (DMPA) or the levonorgestrel-releasing intrauterine system (LNG-IUS). ResultsWomen using COCs [adjusted odds ratio (aOR) 0.29, 95% confidence interval (CI) 0.13–0.64] and DMPA (aOR 0.34, 95% CI 0.13–0.89), but not LNG-IUS (aOR 1.55, 95% CI 0.72–3.35), were less likely to be colonized by BV-associated bacteria relative to women who used condoms. Women using COCs (aOR 1.94, 95% CI 1.25–3.02) were more likely to be colonized by beneficial H2O2-producing Lactobacillus species compared with women using condoms, while women using DMPA (aOR 1.09, 95% CI 0.63–1.86) and LNG-IUS (aOR 0.74, 95% CI 0.48–1.15) were not. ConclusionsUse of COCs is significantly associated with increased vaginal colonization by healthy lactobacilli and reduced BV-associated taxa. ImplicationsCOC use may positively influence gynecologic health through an increase in healthy lactobacilli and a decrease in BV-associated bacterial taxa.

Vaginal Protection by H2O2-Producing Lactobacilli.

Background:Peroxide-producing lactobacilli provide protection from infection for the female reproductive tract. However, in vitro studies demonstrated that H2O2-produced by Lactobacillus is not the cause of inhibition of pathogens. It is not exactly known how H2O2-producing lactobacilli are involved in the protection of the vaginal environment.Objectives:This study aimed to evaluate the importance of the interaction between H2O2-producing lactobacilli and their host for the resistance of the vaginal biotope.Materials and Methods:In this study, we used vaginal lactobacilli (11 H2O2-roducing strains and 11 non-H2O2-producing strains). The influence of epithelial cells on the growth and antibacterial activity of lactobacilli were evaluated. The effects of lactobacilli on the antibacterial activity of the epithelial cells, muramidase and lactoferrin were also determined.Results:Vaginal epithelial cells stimulated the growth and antibacterial activity of H2O2-producing lactobacilli in a greater extent than that of the non-H2O2-producing lactobacilli. Mainly, the H2O2-producing lactobacilli were capable of increasing the activity of the host antimicrobial peptides (muramidase and lactoferrin) as well as the antibacterial activity of the epithelial cells.Conclusions:The involvement of the peroxide-producing lactobacilli in the protection of vagina was due to their ability to effectively interact with the host. This is expressed on one side to stimulate the growth and antagonistic activity of lactobacilli and on the other side to increase the antibacterial activity of the host defense factors (muramidase, lactoferrin and metabolites of epithelial cells).

Hydrogen Peroxide-Producing Lactobacilli Are Associated With Lower Levels of Vaginal Interleukin-1β, Independent of Bacterial Vaginosis.

The presence of hydrogen peroxide (H2O2)-producing lactobacilli in the vagina is associated with decreased rates of preterm birth and HIV acquisition. We hypothesize that this is due to immunomodulatory effects of these species. Concentrations of interleukin (IL)-1β, IL-6, IL-8, secretory leukocyte protease inhibitor, and human β-defensin 2 were quantified from vaginal swabs from 4 groups of women: women with and without bacterial vaginosis (BV) by Nugent score, further stratified by detection of H2O2-producing lactobacilli by semiquantitative culture. Ten quantitative polymerase chain reaction assays characterized the presence and quantity of select Lactobacillus and BV-associated species in each group. Levels of immune markers and bacteria were compared between the 4 groups using analysis of variance, Kruskal-Wallis, Mann-Whitney U, or χ tests. Swabs from 110 women from 4 groups were included: 26 had a normal Nugent score (BV-), and no H2O2-producing lactobacilli detected (H2O2-); 47 were BV-, H2O2+; 27 BV+, H2O2-; and 10 BV+, H2O2+. The groups were similar in age, marital status, and reproductive history, but not ethnicity: the BV-, H2O2- group had more white participants (P = 0.02). In women with and without BV, IL-1β was lower in the H2O2+ groups. Human β-defensin 2 was lowest in BV+ H2O2- women and highest in BV-, H2O2-. Secretory leukocyte protease inhibitor was lower in women with BV and did not differ by the presence of H2O2-producing lactobacilli. In regression analysis, higher quantities of Lactobacillus crispatus were associated with lower quantities of IL-1β. Detection and quantity of BV-associated species by quantitative polymerase chain reaction was significantly different between women with and without BV, but not between women with and without H2O2-producing lactobacilli within those groups. The presence of H2O2-producing lactobacilli is associated with lower levels of some vaginal proinflammatory cytokines, even in women with BV.

Long-term Effect of Depot Medroxyprogesterone Acetate on Vaginal Microbiota, Epithelial Thickness and HIV Target Cells

Depot medroxyprogesterone acetate (DMPA) has been linked to human immunodeficiency virus type 1 (HIV-1) acquisition. Vaginal microbiota of women using DMPA for up to 2 years were cultured. Mucosal immune cell populations were measured by immunohistological staining. Over 12 months, the proportion with H2O2-positive lactobacilli decreased (n = 32; 53% vs 27%; P = .03). Median vaginal CD3(+) cells also decreased (n = 15; 355 vs 237 cells/mm(2); P = .03), as did CD3(+)CCR5(+) cells (195 vs 128 cells/mm(2); P = .04), HLA-DR(+) cells (130 vs 96 cells/mm(2); P = .27), and HLA-DR(+)CCR5(+) cells (18 vs 10 cells/mm(2); P = .33). DMPA contraception does not increase vaginal mucosal CCR5(+) HIV target cells but does decrease CD3(+) T lymphocytes and vaginal H2O2-producing lactobacilli.

S1-Guideline on Bacterial Vaginosis in Gynecology and Obstetrics: Long version - AWMF Guideline, registration no. 015/028, July 2013 Langfassung - AWMF-Register Nr. 015/028, Juli 2013.

Normal vaginal flora of sexually mature women consists of lactobacilli, transient or commensal anaerobic and aerobic bacteria, and Candida species from skin and gut flora. The normal pH value of vaginal flora is 3.8–4.4. Lactobacilli predominate in the vaginal flora, primarily L. crispatus, L. gasseri, L. iners and L. jensenii, depending on ethnicity. Normal pH values differ significantly between ethnicities, ranging from 3.8 to 5.2. Some healthy women have no lactobacilli in their vaginal flora; the percentage of women with lactobacilli differs depending on ethnicity; the percentage for Caucasian women is around 9 %, for Hispanic and African women the percentage is more than 30 % with normal pH values of around 5 14, 43. At present, there are no studies into this issue for Europe. Bacterial vaginosis (BV) is the most common microbiological disorder of the vaginal flora in sexually mature women. The prevalence of BV differs, depending on ethnicity; it is 2.4 times more common in women of African descent 13. In Europe, the prevalence ranges from 5 % in women who come for regular gynecological check-ups to more than 30 % in women treated in clinics for sexually transmitted diseases. The reported prevalence in pregnant women is between 7 and 22 % 3, 9, 15, 22, 25. Psychosocial stress is a significant risk factor for BV 39. There are also indications of gene–environment interactions as additional risk factors and of gene polymorphisms affecting genetic control of the individualʼs immune response to BV 35. The abnormal oral conditions of periodontal disease have been found to be significantly correlated with disturbed vaginal flora in BV 46. Vitamin D deficiency was identified as a risk factor for BV in pregnant women 13. Microarray technology has been used to detect microorganisms associated with BV; in addition to Gardnerella (G.) vaginalis and Atopobium (A.) vaginae, bacteria of the genera Megasphaera, Dialister, Mobiluncus, Prevotella, Leptotrichia, Sneathia, Peptostreptococcus and others were identified 4, 14. There are several strains of G. vaginalis with different properties 6. The most common cause of BV is probably sexual transmission 6, 7, 10, 42, 53. Vitamin D deficiency is also being discussed as a risk factor for BV 13. Typically, the numbers of H2O2-producing lactobacilli species are reduced in women with BV compared to women without BV 8. Only around 50 % of affected women present with characteristic symptoms such as increased homogeneous vaginal discharge or a fishy odor on alkalinization 26. Many women with BV remain asymptomatic. Increased vaginal discharge can cause vulvar irritation.

Consistent Condom Use Increases the Colonization of Lactobacillus crispatus in the Vagina

BackgroundNon-hormonal contraception methods have been widely used, but their effects on colonization by vaginal lactobacilli remain unclear.ObjectiveTo determine the association between non-hormonal contraception methods and vaginal lactobacilli on women’s reproductive health.MethodsThe cross-sectional study included 164 healthy women between 18–45 years of age. The subjects were divided into different groups on the basis of the different non-hormonal contraception methods used by them. At the postmenstrual visit (day 21 or 22 of the menstrual cycle), vaginal swabs were collected for determination of Nugent score, quantitative culture and real-time polymerase chain reaction (PCR) of vaginal lactobacilli. The prevalence, colony counts and 16S rRNA gene expression of the Lactobacillus strains were compared between the different groups by Chi-square and ANOVA statistical analysis methods.ResultsA Nugent score of 0–3 was more common in the condom group (93.1%) than in the group that used an interuterine device(IUD) (75.4%), (p = 0.005). The prevalence of H2O2-producing Lactobacillus was significantly higher in the condom group (82.3%) than in the IUD group (68.2%), (p = 0.016). There was a significant difference in colony count (mean ± standard error (SE), log10colony forming unit (CFU)/ml) of H2O2-producing Lactobacillus between condom users (7.81±0.14) and IUD users (6.54±0.14), (p = 0.000). The 16S rRNA gene expression (mean ± SE, log10copies/ml) of Lactobacillus crispatus was significantly higher in the condom group (8.09±0.16) than in the IUD group (6.03±0.18), (p = 0.000).ConclusionConsistent condom use increases the colonization of Lactobacillus crispatus in the vagina and may protect against both bacterial vaginosis (BV) and human immunodeficiency virus (HIV).

P3.059 Effect of Vaginal Washing on Lactobacillus Colonisation in HIV-Negative Kenyan Women

BackgroundVaginal washing has been associated with an increased risk of bacterial vaginosis (BV) and a decreased likelihood of vaginal Lactobacillus colonisation. We sought to determine whether a lower prevalence of...

Selection, Phenotyping and Identification of Acid and Hydrogen Peroxide Producing Bacteria from Vaginal Samples of Canadian and East African Women

The common but poorly understood condition known as bacterial vaginosis (BV) increases vulnerability to HIV infection and is associated with the absence of H2O2-producing Lactobacillus. Vaginal lactic acid bacteria (LAB) produce anti-HIV factors such as organic acids and hydrogen peroxide (H2O2), and may bind and inactivate HIV particles during scavenging of mannose. These factors define potential criteria for initial selection of candidate probiotics to block heterosexual transmission of HIV. Therefore, the primary goal of this study was to characterize acid production on mannose and H2O2 production in vaginal isolates from Canadian adolescents (192 isolates, 16 individuals) and commercial sex workers in Nairobi, Kenya (576 isolates, 96 individuals). Selection of isolates from H2O2-detecting media suggested an idiosyncratic individual-level profile and extensive phenotypic diversity, including the identification of a subset of “double-strong” acid- and H2O2-producers with phenotypes similar to well-characterized probiotic strains. Molecular fingerprinting of all isolates by capillary electrophoresis of 16S-23S rRNA interspacer amplicons was coupled with chaperonin-60 universal target (cpn60 UT) sequencing in a subset, tentatively identifying 96% of isolates although only 19% were sequenced. Most isolates belonged to Lactobacillus, Streptococcus, Bifidobacterium or Gardnerella, with a total of 37 species in 15 genera, as well as 5 potentially novel organisms, identified in this study. This sensitivity was likely enhanced by phenotype-based selection on two chromogenic media formulations. Identification of double-strong isolates may provide a rational basis for selection and further characterization of vaginal probiotics, with potential application as part of HIV prevention initiatives in western Canada and East Africa.

Effect of Sexual Activity on Vaginal Colonization With Hydrogen Peroxide-Producing Lactobacilli and Gardnerella vaginalis

Bacterial vaginosis is associated with sexual activity, but mechanisms for this association are unclear. Cross-sectional analysis of data from women reporting sex with women who provided information on sexual behaviors as part of a study of vaginal bacteria was conducted. Vaginal bacteria were detected by semiquantitative culture. Binomial regression with log-link evaluated associations between detection of bacteria and sexual behaviors reported to occur before enrollment. Linear regression evaluated associations between these behaviors and quantity of bacteria. Of the 320 women, 216 (68%) were colonized with H2O2-producing lactobacilli and 142 (44%) with Gardnerella vaginalis. Colonization with G. vaginalis was associated with >20 digital-vaginal sex acts (risk ratio, 2.01; 1.22, 3.29) or >10 toy-vaginal acts in the past 3 months (risk ratio, 1.76; 1.32, 2.36). Quantity of H2O2-producing lactobacilli was 1.3 log lower in colonized women reporting >10 acts of insertive vaginal sex-toy use in the past 3 months (95% confidence interval: -2.04, -0.56), 1.19 log lower with toy-vaginal sex in past 7 days (-1.75, -0.62), and 0.78 log lower in women sharing toys with a partner (-1.25, -0.31). Vaginal insertive use and sharing of sex toys were associated with decreased quantities of H2O2-producing lactobacilli and higher risk of colonization with G. vaginalis.

Topical Penile Microbicide Use by Men to Prevent Recurrent Bacterial Vaginosis in Sex Partners: A Randomized Clinical Trial

Bacterial vaginosis (BV) recurs frequently after metronidazole treatment. This randomized, single-masked clinical trial evaluated the efficacy of topical application of 62% ethyl alcohol in emollient gel (gel) to the penis by male partners of women diagnosed with BV for preventing post-treatment BV recurrence. Among 587 Kenyan women presenting with vulvovaginal symptoms, 236 had BV (vaginal Gram stain Nugent score >=7), of whom 223 (94.3%) agreed, along with their partners, to be randomized: 115 to the intervention and 108 to the control arm. In the intervention arm, male partners agreed to apply gel each morning, and before and after sexual intercourse. All couples received counseling, condoms, and syndromic treatment of sexually transmitted infection symptoms. Follow-up visits were scheduled 1 week, 1 month, and 2 months postenrollment, with vaginal Gram stains at every visit and culture for H2O2-producing lactobacilli at the 2-month visit. The primary outcome was time to diagnosis of BV during follow-up. In the primary intent-to-treat analysis, diagnosis of BV was significantly more frequent in the intervention arm (hazard ratio: 1.44, 95% confidence interval: 1.01–2.04). After adjustment for baseline covariates, the hazard ratio was 1.39 (95% confidence interval: 0.98–1.99). At the 2-month visit, prevalences of any vaginal lactobacilli or of H2O2-producing lactobacilli did not differ appreciably in the 2 study arms (P = 0.81 and 0.32, respectively). Daily use of the 62% ethyl alcohol gel by men before and after sex significantly increased persistence or early recurrence of BV in their partners through 2 months after metronidazole treatment. However, no difference was observed in prevalences of vaginal lactobacilli within this same period.

Subtle perturbations of genital microflora alter mucosal immunity among low-risk pregnant women

Alteration in the vaginal flora has been associated with adverse pregnancy outcomes. The objective of this study was to examine the impact of changes in individual microflora on genital immunity among low-risk pregnant women in early pregnancy. Cross-sectional study. Large, tertiary care, academic hospital clinic. Low-risk women were enrolled prior to 14 weeks' gestation. Women were included if they had no medical or previous obstetrical complications, were non-smokers, had no sexually transmitted infections and no intercourse in the last 48 hours. Consenting women underwent speculum examination for collection of vaginal culture and Dacron swabs for cytokine analysis. Semi-quantitative vaginal cultures were performed in a reference laboratory. Concentrations of immune mediators were compared in the presence of various organisms. Concentrations were converted to multiples of the median to standardize the values of each mediator. Regression analyses were performed to control for race. We enrolled 47 women. The frequencies of genital microorganisms were: H(2)O(2) -producing lactobacilli (70%), Ureaplasma urealyticum (66%), Gardnerella vaginalis (45%), anaerobic non-pigmented Gram-negative rods (ANPGNR, 40%), anaerobic pigmented Gram-negative rods (APGNR, 17%). After adjusting for race and body mass index, interleukin-1β, interferon-γ, tumor necrosis factor-α and granulocyte macrophage-colony stimulating factor were increased in the presence of G. vaginalis, ANPGNR, and APGNR. There was no consistent impact on the other markers of immune activation. The presence of individual species impacts genital immunity among low-risk pregnant women. Perturbations in genital immunity could partially explain heterogeneity in adverse pregnancy outcomes.

A Phase I Randomized Placebo Controlled Trial of the Safety of 3% SPL7013 Gel (VivaGel®) in Healthy Young Women Administered Twice Daily for 14 Days

ObjectiveTo assess the safety of VivaGel® used vaginally twice daily for 14 days among healthy, sexually-abstinent women, aged 18–24 years in the USA and Kenya.DesignRandomized placebo controlled trial.MethodsParticipants were randomized 2∶1, VivaGel to placebo. Safety was assessed by comparing genitourinary (GU) adverse events (AEs), colposcopy findings, vaginal lactobacilli and laboratory abnormalities by arm.ResultsFifty-four women were enrolled; 35 in the VivaGel arm and 19 in the placebo arm. Twenty-six (74%) and 10 (53%) women reported taking all doses of VivaGel and placebo, respectively. No grade 3 or 4 AEs, or serious AEs occurred. Twenty-five (71%) participants in the VivaGel arm compared to 10 (53%) participants in the placebo arm had at least one grade 1 or 2 GU AE associated with product use (RR = 1.4, 95% CI 0.8-2.2). All seven grade 2 GU AEs associated with product use occurred among four women in the VivaGel arm. Vulvar and cervical erythema, cervical lesions, symptomatic BV, urinary frequency and metrorrhagia were more common in the VivaGel arm than the placebo arm. Twenty-nine (83%) participants in the VivaGel arm had a colposcopic finding compared to 10 (53%) participants in the placebo arm (RR = 1.6, 95%CI = 1.0-2.5). Two women in the VivaGel arm prematurely discontinued product use themselves due to a reported GU AE. Persistence of H2O2-producing and non-producing lactobacilli did not differ by study arm.ConclusionsGU AEs and colposcopic findings consistent with mild epithelial irritation and inflammation occurred more commonly among women in the VivaGel arm.Trial RegistrationClinicalTrials.gov NCT003311032

Cervicovaginal fluid and semen block the microbicidal activity of hydrogen peroxide produced by vaginal lactobacilli.

BackgroundH2O2 produced by vaginal lactobacilli is believed to protect against infection, and H2O2-producing lactobacilli inactivate pathogens in vitro in protein-free salt solution. However, cervicovaginal fluid (CVF) and semen have significant H2O2-blocking activity.MethodsWe measured the H2O2 concentration of CVF and the H2O2-blocking activity of CVF and semen using fluorescence and in vitro bacterial-exposure experiments.ResultsThe mean H2O2 measured in fully aerobic CVF was 23 ± 5 μM; however, 50 μM H2O2 in salt solution showed no in vitro inactivation of HSV-2, Neisseria gonorrhoeae, Hemophilus ducreyii, or any of six BV-associated bacteria. CVF reduced 1 mM added H2O2 to an undetectable level, while semen reduced 10 mM added H2O2 to undetectable. Moreover, the addition of just 1% CVF supernatant abolished in vitro pathogen-inactivation by H2O2-producing lactobacilli.ConclusionsGiven the H2O2-blocking activity of CVF and semen, it is implausible that H2O2-production by vaginal lactobacilli is a significant mechanism of protection in vivo.

Prospective study of correlates of vaginal Lactobacillus colonisation among high-risk HIV-1 seronegative women

Objective: Vaginal colonisation with Lactobacillus species is characteristic of normal vaginal ecology. The absence of vaginal lactobacilli, particularly hydrogen peroxide (H2O2)-producing isolates, has been associated with symptomatic bacterial vaginosis (BV)...

Analysis of Vaginal Lactobacilli from Healthy and Infected Brazilian Women

Culture-dependent PCR-amplified rRNA gene restriction analysis and culture-independent (PCR-denaturing gradient gel electrophoresis) methodologies were used to examine vaginal lactobacilli from Brazilian women who were healthy or had been diagnosed with vulvovaginal candidiasis (VVC) or bacterial vaginosis. Only Lactobacillus crispatus was detected accordingly by both methods, and H(2)O(2)-producing lactobacilli were not associated with protection against VVC.

Stay It with Flora: Maintaining Vaginal Health as a Possible Avenue for Prevention of Human Immunodeficiency Virus Acquisition

mucosal surface, the vagina may be colonized by a variety of bacteria, fungi, and other potential pathogens. A normal vaginal flora is predominately composed of Lactobacillus species, with low diversity [1]. Lactobacilli provide significant health benefits to the host by decreasing the vaginal pH through lactic acid production, generating H2O2 and bacteriocins, and stimulating the local immune system [2], all of which serve as barriers to pathogens. Thus, an abnormal vaginal flora may have significant implications for the transmission of human immunodeficiency virus (HIV) and other sexually transmitted infections (STIs). It is therefore unfortunate that, in the real world, a normal (i.e., lactobacilli-predominant) vaginal flora is not the norm. The composition of the vaginal flora within a population constitutes a spectrum. In some individuals, H2O2producing Lactobacillus species predominate, whereas in others, the flora may include an increasing proportion of various species, such as Gardnerella vaginalis, Mycoplasma hominis, and gramnegative and gram-positive anaerobes, including Prevotella organisms [1, 3]. This spectrum is often quantified numerically by means of the Nugent scoring system, with flora classified as normal, intermediate, or bacterial vaginosis [4]. On the basis of this system, the vaginal flora is actually abnormal (i.e., it is classified as intermediate or vaginosis) in at least half of women. This abnormal status