scholarly journals Analysis of adherence, biofilm formation and cytotoxicity suggests a greater virulence potential of Gardnerella vaginalis relative to other bacterial-vaginosis-associated anaerobes

Microbiology ◽  
2010 ◽  
Vol 156 (2) ◽  
pp. 392-399 ◽  
Author(s):  
Jennifer L. Patterson ◽  
Annica Stull-Lane ◽  
Philippe H. Girerd ◽  
Kimberly K. Jefferson
Keyword(s):  
Bacterial Vaginosis ◽  
Cytotoxic Activity ◽  
Bacterial Species ◽  
Opportunistic Pathogen ◽  
Collective Effects ◽  
Gardnerella Vaginalis ◽  
Childbearing Age ◽  
Virulence Potential ◽  
Virulence Properties

Worldwide, bacterial vaginosis (BV) is the most common vaginal disorder in women of childbearing age. BV is characterized by a dramatic shift in the vaginal microflora, involving a relative decrease in lactobacilli, and a proliferation of anaerobes. In most cases of BV, the predominant bacterial species found is Gardnerella vaginalis. However, pure cultures of G. vaginalis do not always result in BV, and asymptomatic women are sometimes colonized with low numbers of G. vaginalis. Thus, there is controversy about whether G. vaginalis is an opportunistic pathogen and the causative agent of many cases of BV, or whether BV is a polymicrobial condition caused by the collective effects of an altered microbial flora. Recent studies of the biofilm-forming potential and cytotoxic activity of G. vaginalis have renewed interest in the virulence potential of this organism. In an effort to tease apart the aetiology of this disorder, we utilized in vitro assays to compare three virulence properties of G. vaginalis relative to other BV-associated anaerobes. We designed a viable assay to analyse bacterial adherence to vaginal epithelial cells, we compared biofilm-producing capacities, and we assessed cytotoxic activity. Of the BV-associated anaerobes tested, only G. vaginalis demonstrated all three virulence properties combined. This study suggests that G. vaginalis is more virulent than other BV-associated anaerobes, and that many of the bacterial species frequently isolated from BV may be relatively avirulent opportunists that colonize the vagina after G. vaginalis has initiated an infection.

scholarly journals Using an in-vitro biofilm model to assess the virulence potential of Bacterial Vaginosis or non-Bacterial Vaginosis Gardnerella vaginalis isolates

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Joana Castro ◽  
Patrícia Alves ◽  
Cármen Sousa ◽  
Tatiana Cereija ◽  
Ângela França ◽  
...  
Keyword(s):  
Bacterial Vaginosis ◽  
Gardnerella Vaginalis ◽  
Biofilm Model ◽  
Virulence Potential

scholarly journals Bifidobacterium adolescentis shows potential to strengthen host defence against gastrointestinal infection via inhibition of the opportunistic pathogen Candida albicans and stimulation of human-isolated macrophages killing capacity in vitro

2020 ◽  
Vol 2 (7A) ◽  
Author(s):  
Liviana Ricci ◽  
Joanna Mackie ◽  
Megan D. Lenardon ◽  
Caitlin Jukes ◽  
Ahmed N. Hegazy ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Bacterial Species ◽  
Opportunistic Pathogen ◽  
Limited Information ◽  
Human Gut ◽  
Bifidobacterium Adolescentis ◽  
Host Immune Responses ◽  
Opportunistic Fungal Pathogen ◽  
Antimicrobial Metabolites

The human gut microbiota enhances the host’s resistance to enteric pathogens via colonisation resistance, a phenomenon that is driven by multiple mechanisms, such as production of antimicrobial metabolites and activation of host immune responses. However, there is limited information on how individual gut bacterial species, particularly many of the dominant anaerobes, might impact the host’s defence. This study investigated the potential of specific human gut isolates to bolster the host’s resistance to infection. First, by antagonising the opportunistic fungal pathogen Candida albicans, and secondly, by modulating the killing capacity of human-isolated macrophages in vitro. Co-culturing C. albicans with faecal microbiota from different healthy individuals revealed varying levels of fungal inhibition. In vitro assays with a panel of representative human gut anaerobes confirmed that culture supernatants from certain bacterial isolates, in particular of Bifidobacterium adolescentis, significantly inhibited C. albicans growth. Mechanistic studies revealed that microbial fermentation acids including acetate and lactate, in combination with the associated decrease in pH, were strong drivers of this inhibitory activity. In the second in vitro assay, human-isolated macrophages were exposed to bacterial supernatants, and subsequently tested for their capacity to eliminate adherent-invasive Escherichia coli. Among the gut anaerobes tested, B. adolescentis was revealed to exert the strongest immunostimulatory and killing effect when compared to the unstimulated macrophages control. B. adolescentis is known to be stimulated by dietary consumption of resistant starch andmay therefore represent an attractive target for the development of probiotic and prebiotic interventions tailored to enhancethe host’s natural defences against infection.

scholarly journals Efficacy and safety of a novel vaginal medical device in recurrent bacterial vaginosis: an international multicentre clinical trial

2019 ◽  
Author(s):  
Filippo Murina ◽  
Ciprian Crişan ◽  
Marius Biriş ◽  
Daniela Sîrbu ◽  
Dionisio Franco Barattini ◽  
...  
Keyword(s):  
Bacterial Vaginosis ◽  
Medical Device ◽  
Recurrence Rate ◽  
Vaginal Flora ◽  
Gardnerella Vaginalis ◽  
Lactobacillus Species ◽  
Published Data ◽  
Childbearing Age ◽  
Open Label ◽  
Adverse Pregnancy

ABSTRACTSeveral risk factors have been identified but the etiology and pathogenesis of Bacterial vaginosis (BV) are still not completely understood, and the recurrence rate of BV remains high despite adequate chemotherapy treatment.The primary objective of the study was to assess the effectiveness of a new vaginal medical device, which contains polycarbophil, 0.04 % lauryl glucoside, and glycerides (Polybactum®– Effik Italia), in reducing BV recurrence rate.This was a multicenter, open label, not comparative study performed in Italy and Romania. Female subjects over 18-years-old affected by recurrent BV were included. The latest episode was diagnosed by Amsel criteria 6-9 days before the start of the study and treated with vaginal metronidazole (gel 0.75% mg for 5 days or ovules 500 mg for 7 days). The recurrence was defined by at least 2 episodes in the previous 12 months. Polybactum®vaginal ovules, day 1-4-7, were started within the 12th and the 24th hr after the end of metronidazole therapy and repeated monthly for 3 cycles.The first 41 patients enrolled were evaluated for an interim analysis 6 months after the study started; 2 patients interrupted the trial, leaving 39 evaluable subjects. The recurrence rate was significantly reduced compared to previous published data (10.26% vs 40% p<0.001). In 35 patients without recurrence, the assessment of Lactobacillus vaginal flora performed by phase contrast microscopy evidenced a significant improvement form baseline (p=0.022) The Investigator global assessment of tolerability was excellent in 38 out of 39 cases.IMPORTANCEBacterial vaginosis (BV) is the most common vaginal disorder in women of childbearing age. In BV, Lactobacillus species, which are predominant in a healthy vaginal flora, are replaced by anaerobes, mainly Gardnerella vaginalis. BV is responsible for more than 60% of vulvovaginal infections and has been linked to serious, potentially life-threatening conditions, including: pelvic inflammatory disease, postoperative infections, acquisition and transmission of the human immunodeficiency virus, preterm birth, and several adverse pregnancy outcomes. Our research showed that 3 monthly cycles of Polybactum®ovules administered after one course of metronidazole vaginal therapy can reduce the rate of Bacterial vaginosis recurrence and improve the vaginal milieu, favouring the growth of vaginal lactobacillus species. Taken together our results confirm that Polibactum®is a safe and effective treatment to reduce BV recurrence rate after a first line therapy with metronidazole.

scholarly journals Poly (acetyl arginyl) glucosamine attenuates Pseudomonas aeruginosa in a rat lung infection model

2021 ◽  
Author(s):  
Bryan Garcia ◽  
Melissa S. McDaniel ◽  
Allister J. Loughran ◽  
J. Dixon Johns ◽  
Vidya Narayanaswamy ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Respiratory Infections ◽  
Bacterial Species ◽  
Membrane Integrity ◽  
Opportunistic Pathogen ◽  
Infection Model ◽  
Total Biomass ◽  
Chronic Infections

Pseudomonas aeruginosa is a common opportunistic pathogen that can cause chronic infections in multiple disease states, including respiratory infections in patients with cystic fibrosis (CF) and non-CF bronchiectasis. Like many opportunists, P. aeruginosa forms multicellular biofilm communities that are widely thought to be an important determinant of bacterial persistence and resistance to antimicrobials and host immune effectors during chronic/recurrent infections. Poly (acetyl, arginyl) glucosamine (PAAG) is a glycopolymer which has antimicrobial activity against a broad range of bacterial species, and also has mucolytic activity which can normalize rheologic properties of cystic fibrosis mucus. In this study, we sought to evaluate the effect of PAAG on P. aeruginosa bacteria within biofilms in vitro, and in the context of experimental pulmonary infection in a rodent infection model. PAAG treatment caused significant bactericidal activity against P. aeruginosa biofilms, and a reduction in the total biomass of preformed P. aeruginosa biofilms on abiotic surfaces, as well as on the surface of immortalized cystic fibrosis human bronchial epithelial cells. Studies of membrane integrity indicated that PAAG causes changes to P. aeruginosa cell morphology and dysregulates membrane polarity. PAAG treatment reduced infection and consequent tissue inflammation in experimental P. aeruginosa rat infections. Based on these findings we conclude that PAAG represents a novel means to combat P. aeruginosa infection, which may warrant further evaluation as a therapeutic.

scholarly journals Crystal Violet Staining Alone Is Not Adequate to Assess Synergism or Antagonism in Multi-Species Biofilms of Bacteria Associated With Bacterial Vaginosis

2022 ◽  
Vol 11 ◽  
Author(s):  
Joana Castro ◽  
Ângela Lima ◽  
Lúcia G. V. Sousa ◽  
Aliona S. Rosca ◽  
Christina A. Muzny ◽  
...  
Keyword(s):  
Bacterial Vaginosis ◽  
Crystal Violet ◽  
Single Species ◽  
Gardnerella Vaginalis ◽  
Individual Species ◽  
Vaginal Epithelial Cells ◽  
Prevotella Bivia ◽  
Depth Study ◽  
Biofilm Quantification

Bacterial Vaginosis (BV) involves the presence of a multi-species biofilm adhered to vaginal epithelial cells, but its in-depth study has been limited due to the complexity of the bacterial community, which makes the design of in vitro models challenging. Perhaps the most common experimental technique to quantify biofilms is the crystal violet (CV) staining method. Despite its widespread utilization, the CV method is not without flaws. While biofilm CV quantification within the same strain in different conditions is normally accepted, assessing multi-species biofilms formation by CV staining might provide significant bias. For BV research, determining possible synergism or antagonism between species is a fundamental step for assessing the roles of individual species in BV development. Herein, we provide our perspective on how CV fails to properly quantify an in vitro triple-species biofilm composed of Gardnerella vaginalis, Fannyhessea (Atopobium) vaginae, and Prevotella bivia, three common BV-associated bacteria thought to play key roles in incident BV pathogenesis. We compared the CV method with total colony forming units (CFU) and fluorescence microscopy cell count methods. Not surprisingly, when comparing single-species biofilms, the relationship between biofilm biomass, total number of cells, and total cultivable cells was very different between each tested method, and also varied with the time of incubation. Thus, despite its wide utilization for single-species biofilm quantification, the CV method should not be considered for accurate quantification of multi-species biofilms in BV pathogenesis research.

scholarly journals Antagonism and synergism in Gardnerella vaginalis strains isolated from women with bacterial vaginosis

2010 ◽  
Vol 59 (8) ◽  
pp. 891-897 ◽  
Author(s):  
G. S. Teixeira ◽  
K. L. K. Soares-Brandão ◽  
K. M. G. R. Branco ◽  
J. L. M. Sampaio ◽  
R. M. D. Nardi ◽  
...  
Keyword(s):  
Bacterial Vaginosis ◽  
Chemical Nature ◽  
Growth Conditions ◽  
Antagonistic Activity ◽  
Gardnerella Vaginalis ◽  
Ecological Role ◽  
Micro Organisms

Antagonistic and synergistic substances are important for interactions between micro-organisms associated with human body surfaces, either in healthy or in diseased conditions. In the present study, such compounds produced by Gardnerella vaginalis strains isolated from women with bacterial vaginosis (BV) were detected in vitro and the antagonistic ones were partially characterized. Among 11 G. vaginalis strains tested, all showed antagonistic activity against at least one of the 22 indicator bacteria assayed. Interestingly, for some of these strains, antagonism reverted to synergism, favouring one of the indicator strains (Peptostreptococcus anaerobius) when the growth medium was changed. Partial characterization of antagonistic substances suggested a bacteriocin-like chemical nature. Depending on growth conditions, G. vaginalis isolated from women with BV produced antagonistic or synergistic compounds for other bacterial components of the vaginal ecosystem. This is the first report to our knowledge of the production of antagonistic and/or synergistic substances by G. vaginalis. This ability may be a pivotal factor in understanding BV and the ecological role of this bacterium in the vaginal environment.

Sign in / Sign up

Export Citation Format

Share Document