Membrane vesicles of Lactobacillus gasseri ATCC 19992 disrupt biofilms of vaginal pathogens

Membrane vesicles (MVs) are bioactive, nano-sized entities produced by all organisms. MVs of L. gasseri ATCC 19992 were isolated and their effect on the biofilms of vaginal pathogens, G. vaginalis and S. aureus was studied. The L. gasseri MVs resulted in significant disruption of biofilms of the vaginal pathogens.

Quantification of Gardnerella vaginalis, Atopobium vaginae and Lactobacillus spp. in bacterial vaginosis

INTRODUCTION

The aim of the study was to investigate prevalence of bacteria most frequently associated with bacterial vaginosis using Amsel's criteria as well as to quantify these bacteria by real-time PCR and to explore the difference in their quantity between healthy and bacterial vaginosis samples.

METHODOLOGY

For classification of vaginal discharge samples Amsel's criteria have been used. To detect and quantify Gardnerella vaginalis Atopobium vaginae, Lactobacillus spp. and total vaginal microbiome, real-time PCR has been applied.

RESULTS

According to results of our study Amsel's criteria matched well with real-time PCR diversification of healthy women and women with BV. Nevertheless, real-time PCR has been more sensitive in diagnosis of bacterial vaginosis. DNA quantification of bacteria demonstrated that mutual abundance of G.vaginalis and A. vaginae was good bacterial vaginosis marker . On the contrary, Lactobacillus spp. was present in high amount in both healthy and bacterial vaginosis samples, but ratio of investigated bacteria was different between them. In fact, G. vaginalis and A. vaginae comprised only 0.1% of total microbiome in healthy, whereas Lactobacillus spp. took 99.3% of it. Nonetheless, in bacterial vaginosis, G. vaginalis and A. vaginae made up 34.4% of total microbiome, while Lactobacillus spp. was 21.6%.

CONCLUSIONS

According to the results of our study real-time PCR analysis was more sensitive in diagnosis of bacterial vaginosis than Amsel's method, as well as it represented fine tool in making a difference between microbial entities in healthy and bacterial vaginosis samples.

Strong correlation between urine and vaginal swab samples for bacterial vaginosis

Background

Vaginal swabs have been traditionally used for the diagnosis of bacterial vaginosis (BV). Currently, there are limited studies that have investigated the use of other sample types other than vaginal swabs for the detection of BV from South African populations. This study investigated whether urine can be used for the detection of BV-associated microorganisms in South African pregnant women.

Methods

One-hundred self-collected vaginal swabs and urine samples were obtained from women presenting for antenatal care at King Edward VIII Hospital in Durban. The BD MAX™ vaginal panel assay was used for diagnosing BV and droplet digital polymerase chain reaction was used to quantify Gardnerella vaginalis, Prevotella bivia, Atopobium vaginae and Lactobacillus crispatus. The absolute counts were determined on the QX200 Droplet Reader (Bio-Rad) using the QuantaSoft Software. Data analysis was performed with statistical computing software called R, version 3.6.1.

Results

Median copy numbers obtained for G. vaginalis and P. bivia across urine and swabs in BV-positive samples were not significantly different (p = 0.134 and p = 0.652, respectively). This was confirmed by the correlation analysis that showed a good correlation between the two sample types (G. vaginalis [r = 0.63] and P. bivia [r = 0.50]). However, the data obtained for A. vaginae differed, and a weak correlation between urine and swabs was observed (r = 0.21). Bacterial vaginosis-negative samples had no significant difference in median copy numbers for L. crispatus across the urine and swabs (p = 0.062), and a good correlation between the sample types was noted (r = 0.71).

Conclusion

This study highlights the appropriateness of urine for the detection of microorganisms associated with BV.

Lactobacillus plantarum Lp62 exerts probiotic effects against Gardnerella vaginalis ATCC 49154 in bacterial vaginosis

The severe side-effects elicited by conventional antibiotic therapy and the recurrence of Bacterial vaginosis-associated bacteria and bacterial resistance have led to the development of novel alternative therapies, among which genital probiotics are widely used. In this study, we aimed to evaluate the antimicrobial activities of Lactobacillus plantarum Lp62 and its supernatant against Gardnerella vaginalis, using both in vitro and in vivo approaches. In vitro assays were used to evaluate the viability of the strain and the antimicrobial activities of the supernatant in different pH ranges. An in vivo assay was performed on female BALB/c mice, wherein the animals were divided into eight groups: four control groups and four treated groups (for curative and preventive therapies). After infecting and treating the mice, the animals were killed to quantify the bacterial load using qPCR, evaluate leucocyte cellular response, determine vaginal cytokine levels and perform cytokine tissue gene expression. Our analyses revealed significant activity of the strain and its supernatant against G. vaginalis. Preliminary in vitro tests showed that the strain grew with equal efficiency in different pH ranges. Meanwhile, the presence of halo and inhibition of pathogen growth established the significant activity of the supernatant against G. vaginalis. We observed that both micro-organisms are resident bacteria of mouse microbiota and that the lactobacilli population growth was affected by G. vaginalis and vice versa. We also observed that the treated groups, with their low bacterial load, absence of leucocyte recruitment, reduced cytokine levels in the vaginal lavage and normalized cytokine gene expression, successfully controlled the infection.

Lactiplantibacillus plantarum strains isolated from spontaneously fermented cocoa exhibit potential probiotic properties against Gardnerella vaginalis and Neisseria gonorrhoeae

Background

Probiotics are important tools in therapies against vaginal infections and can assist traditional antibiotic therapies in restoring healthy microbiota. Recent research has shown that microorganisms belonging to the genus Lactobacillus have probiotic potential. Thus, this study evaluated the potential in vitro probiotic properties of three strains of Lactiplantibacillus plantarum, isolated during the fermentation of high-quality cocoa, against Gardnerella vaginalis and Neisseria gonorrhoeae. Strains were evaluated for their physiological, safety, and antimicrobial characteristics.

Results

The hydrophobicity of L. plantarum strains varied from 26.67 to 91.67%, and their autoaggregation varied from 18.10 to 30.64%. The co-aggregation of L. plantarum strains with G. vaginalis ranged from 14.73 to 16.31%, and from 29.14 to 45.76% with N. gonorrhoeae. All L. plantarum strains could moderately or strongly produce biofilms. L. plantarum strains did not show haemolytic activity and were generally sensitive to the tested antimicrobials. All lactobacillus strains were tolerant to heat and pH resistance tests. All three strains of L. plantarum showed antimicrobial activity against the tested pathogens. The coincubation of L. plantarum strains with pathogens showed that the culture pH remained below 4.5 after 24 h. All cell-free culture supernatants (CFCS) demonstrated activity against the two pathogens tested, and all L. plantarum strains produced hydrogen peroxide. CFCS characterisation in conjunction with gas chromatography revealed that organic acids, especially lactic acid, were responsible for the antimicrobial activity against the pathogens evaluated.

Conclusion

The three strains of L. plantarum presented significant probiotic characteristics against the two pathogens of clinical importance. In vitro screening identified strong probiotic candidates for in vivo studies for the treatment of vaginal infections.

Type II Restriction-Modification System from Gardnerella vaginalis ATCC 14018

Intensive horizontal gene transfer may generate diversity and heterogeneity within the genus Gardnerella. Restriction-modification (R-M) systems and CRISPR-Cas are the principal defense tools against foreign DNA in bacteria. Nearly half of the tested Gardnerella spp. isolates harbored the CRISPR-Cas system. Several putative R-M systems of Gardnerella spp. strains were identified in the REBASE database. However, there was no experimental evidence for restriction endonuclease (REase) activity in the isolates. We showed that G. vaginalis strain ATCC 14018 contains the REase R.Gva14018I, which recognizes GGCC and most probably generates blunt ends on cleavage. Bioinformatics evidence and the activity of recombinant methyltransferase M.Gva14018I in vivo indicate that ATCC 14018 possesses a HaeIII-like R-M system. The truncated R.Gva14018I-4 lacking the C-terminal region was expressed in Escherichia coli and displayed wild-type REase specificity. Polyclonal antibodies against R.Gva14018I-4 detected the wild-type REase in the cell lysate of ATCC 14018. The cofactor requirements for activity and bioinformatics analysis indicated that R.Gva14018I belongs to the PD-(D/E)XK family of REases. The REase-like activity was observed in 5 of 31 tested Gardnerella spp. strains, although none of these matched the DNA digestion pattern of R.Gva14018I.

Saccharomyces cerevisiae-based probiotic as novel anti-microbial agent for therapy of bacterial vaginosis

In this study, we demonstrate, for the first time, that Saccharomyces cerevisiae-based probiotic shows an inhibitory effect on Gardnerella vaginalis infection. This effect is likely due to several actions: direct interference with adherence to vaginal tissues, inhibition of sialidase activity, reduction of vaginal epithelial exfoliation. Gardnerella vaginalis does not induce vaginal inflammation and no inflammatory cytokines were, indeed, produced, by the mouse vagina, neither by Gardnerella vaginalis and by the probiotic. Collectively, our data incite to further investigations on Saccharomyces cerevisiae probiotic as a potential prophylactic or therapeutic agent in the vaginosis caused by Gardnerella vaginalis.

Gardnerella vaginalis and Mollicute detection in rectal swabs from men who have sex with men

The numbers of rectal sexually transmitted infections are on the rise especially among men who have sex with men. Males from men who have sex with men population are encouraged to send a rectal swab to the laboratory for sexually transmitted infection screening at their visit to the Genitourinary Medicine Clinic. In healthy asymptomatic males, the range of pathogens tested is limited therefore other pathogens may be left untreated allowing infections to persist among sexual partners. Molecular techniques have revolutionarised sexually transmitted infection testing enabling the detection of previously difficult-to-culture pathogens in extra-genital sites and have increased the evidence base for their clinical significance. The present study tests 107 rectal swabs from men who have sex with men negative for Chlamydia trachomatis and Neisseria gonorrhoeae against quantitative polymerase chain reaction (qPCR) assays targeting five common sexually transmitted bacteria which include Mycoplasma genitalium, Mycoplasma hominis, Ureaplasma urealyticum, Ureaplasma parvum and Gardnerella vaginalis. The pathogenic role of these five bacteria in men who have sex with men is currently unknown. Amongst the 107 patients, a positive qPCR was obtained respectively for G. vaginalis 89 (83.2%); U. urealyticum 26 (24.3%); M. hominis 26 (24.3%); M. genitalium 10 (9.3%) and U. parvum 5 (4.7%). Bacterial loads in single and co-infections were compared for each organism. G. vaginalis and M. hominis loads were significantly ( p = 0.007 and p = 0.005, respectively) higher when co-infecting with at least one other organism. Amongst co-infections, the loads of each organism were assessed to determine possible synergies. G. vaginalis and M. hominis displayed a synergistic pattern ( r = 0.51; p = 0.02) which is in keeping with a similar synergy detected previously in the vagina of women with bacterial vaginosis. This study outlines that potential significant infections are being missed in men who have sex with men population; however, further research is warranted to confirm a pathogenesis in the rectal mucosa before routine screening can be introduced to clinical settings.