Intermittent Lactobacilli-containing Vaginal Probiotic or Metronidazole Use to Prevent Bacterial Vaginosis Recurrence: A Pilot Study Incorporating Microscopy and Sequencing

Bacterial vaginosis (BV) is associated with HIV acquisition and adverse pregnancy outcomes. Recurrence after metronidazole treatment is high. HIV-negative, non-pregnant Rwandan BV patients were randomized to four groups (n=17/group) after seven-day oral metronidazole treatment: behavioral counseling only (control), or counseling plus intermittent use of oral metronidazole, Ecologic Femi+ vaginal capsule (containing multiple Lactobacillus and one Bifidobacterium species), or Gynophilus LP vaginal tablet (L. rhamnosus 35) for two months. Vaginal microbiota assessments at all visits included Gram stain Nugent scoring and 16S rRNA gene qPCR and HiSeq sequencing. All interventions were safe. BV (Nugent 7-10) incidence was 10.18 per person-year at risk in the control group, and lower in the metronidazole (1.41/person-year; p=0.004), Ecologic Femi+ (3.58/person-year; p=0.043), and Gynophilus LP groups (5.36/person-year; p=0.220). In mixed effects models adjusted for hormonal contraception/pregnancy, sexual risk-taking, and age, metronidazole and Ecologic Femi+ users, each compared to controls, had higher Lactobacillus and lower BV-anaerobes concentrations and/or relative abundances, and were less likely to have a dysbiotic vaginal microbiota type by sequencing. Inter-individual variability was high and effects disappeared soon after intervention cessation. Lactobacilli-based vaginal probiotics warrant further evaluation because, in contrast to antibiotics, they are not expected to negatively affect microbiota or cause antimicrobial resistance

Effect of the Pre-erythrocytic Candidate Malaria Vaccine RTS,S/AS01E on Blood Stage Immunity in Young Children

(See the article by Greenhouse et al, on pages 19-26.

Unraveling the role of lactobacilli in the vaginal barrier function and HSV-2 transmission

Humans live in symbiosis with a tremendous number of bacteria, collectively referred to as the microbiota, that play a key role in several host physiological processes and health. While the gut microbiota has received plenty of attention the past decades, the vaginal microbiota is only recently gaining interest as a crucial player in female and reproductive health. The vaginal microbiota of most healthy women is generally dominated by Lactobacillus species, recognized as a biomarker species for vaginal health. These species also play an indispensable role in supporting the host’s defence against a wide variety of bacterial, fungal and viral pathogens. However, a detailed molecular understanding of their adaptation to the vaginal niche and their health promoting and anti-pathogen effects is currently lacking. The goal of this PhD project is therefore to deliver insights on the molecular mechanisms used by lactobacilli to contribute to vaginal health, and to defend against herpes simplex virus type 2 (HSV-2), the main causative agent of genital herpes disease, as a case study viral pathogen in the vaginal tract. Residing at the port of entry of various pathogens causing urogenital and sexually transmitted infections in women, lactobacilli could promote vaginal health by enforcing the vaginal barrier function against these pathogens. As the vaginal barrier is composed of the vaginal epithelium, mucus and the immune system, this PhD research investigated interactions of lactobacilli with the host such as adhesion and immunomodulation as key properties to a healthy vaginal environment. Ultimately, this knowledge will drive more targeted selection criteria for probiotic strains focused on the maintenance/restoration of vaginal health. Given that a vaginal microbiota not dominated by lactobacilli has been identified as a risk factor for HSV-2 infections, a second part of this research focused on the elucidation of putative antiviral mechanisms of action of lactobacilli against HSV-2. Hereto, a platform to study interactions between bacteria, cells and viruses was developed, representing a significant technical challenge of this project. Three antiviral mechanisms were investigated: (1) co-aggregation with virions thereby preventing host cell invasion, (2) competition with attachment/entry receptors of HSV-2 thereby blocking virus adhesion, and (3) stimulation of the innate antiviral immune response of vaginal epithelial cells following viral challenge. Next to delivering pioneer work on Lactobacillus-virus interactions at the molecular level, this PhD findings open new perspectives for microbial management-based prevention and treatment strategies against HSV-2 and potentially other vaginal infections.nrpages: 213status: publishe

Unraveling the role of lactobacilli in the vaginal barrier function and HSV-2 transmission

Humans live in symbiosis with a tremendous number of bacteria, collectively referred to as the microbiota, that play a key role in several host physiological processes and health. While the gut microbiota has received plenty of attention the past decades, the vaginal microbiota is only recently gaining interest as a crucial player in female and reproductive health. The vaginal microbiota of most healthy women is generally dominated by Lactobacillus species, recognized as a biomarker species for vaginal health. These species also play an indispensable role in supporting the host’s defence against a wide variety of bacterial, fungal and viral pathogens. However, a detailed molecular understanding of their adaptation to the vaginal niche and their health promoting and anti-pathogen effects is currently lacking. The goal of this PhD project is therefore to deliver insights on the molecular mechanisms used by lactobacilli to contribute to vaginal health, and to defend against herpes simplex virus type 2 (HSV-2), the main causative agent of genital herpes disease, as a case study viral pathogen in the vaginal tract. Residing at the port of entry of various pathogens causing urogenital and sexually transmitted infections in women, lactobacilli could promote vaginal health by enforcing the vaginal barrier function against these pathogens. As the vaginal barrier is composed of the vaginal epithelium, mucus and the immune system, this PhD research investigated interactions of lactobacilli with the host such as adhesion and immunomodulation as key properties to a healthy vaginal environment. Ultimately, this knowledge will drive more targeted selection criteria for probiotic strains focused on the maintenance/restoration of vaginal health. Given that a vaginal microbiota not dominated by lactobacilli has been identified as a risk factor for HSV-2 infections, a second part of this research focused on the elucidation of putative antiviral mechanisms of action of lactobacilli against HSV-2. Hereto, a platform to study interactions between bacteria, cells and viruses was developed, representing a significant technical challenge of this project. Three antiviral mechanisms were investigated: (1) co-aggregation with virions thereby preventing host cell invasion, (2) competition with attachment/entry receptors of HSV-2 thereby blocking virus adhesion, and (3) stimulation of the innate antiviral immune response of vaginal epithelial cells following viral challenge. Next to delivering pioneer work on Lactobacillus-virus interactions at the molecular level, this PhD findings open new perspectives for microbial management-based prevention and treatment strategies against HSV-2 and potentially other vaginal infections.nrpages: 213status: publishe

Elektroconvulsietherapie bij patiënten met metallische schedelimplantaten

Achtergrond: Elektroconvulsietherapie (ECT) is een doeltreffende behandeling voor stemmingsstoornissen. Er bestaat echter weinig wetenschappelijke consensus over de veiligheid bij patiënten met metallische schedelimplantaten, die een hoger risico lopen op stemmingsstoornissen. Doel: Bundelen van de bestaande literatuur over de veiligheid en doeltreffendheid van ECT bij metallische schedelimplantaten. Methode: We doorzochten PubMed naar relevante casusbeschrijvingen en eerdere overzichtsartikelen gepubliceerd sinds 1950. Resultaten: We vonden 37 relevante casussen. In geen enkele casus trad een complicatie op die toe te schrijven was aan de interactie tussen ECT en een metallisch schedelimplantaat. In 95% van de casussen was het psychiatrisch resultaat positief. Conclusie: Aan de hand van de beschikbare literatuur zijn er geen argumenten dat het gebruik van ECT bij patiënten met metallische implantaten gevaarlijk is. Met de nodige voorzichtigheid en correcte indicatiestelling kan men deze behandeling op individuele basis overwegen

Lactobacillus species as biomarkers and agents that can promote various aspects of vaginal health

The human body is colonized by a vast number of microorganisms collectively referred to as the human microbiota. One of the main microbiota body sites is the female genital tract, commonly dominated by Lactobacillus spp., in approximately 70% of women. Each individual species can constitute approximately 99% of the ribotypes observed in any individual woman. The most frequently isolated species are Lactobacillus crispatus, Lactobacillus gasseri, Lactobacillus jensenii and Lactobacillus iners. Residing at the port of entry of bacterial and viral pathogens, the vaginal Lactobacillus species can create a barrier against pathogen invasion since mainly products of their metabolism secreted in the cervicovaginal fluid can play an important role in the inhibition of bacterial and viral infections. Therefore, a Lactobacillus-dominated microbiota appears to be a good biomarker for a healthy vaginal ecosystem. This balance can be rapidly altered during processes such as menstruation, sexual activity, pregnancy and various infections. An abnormal vaginal microbiota is characterized by an increased diversity of microbial species, leading to a condition known as bacterial vaginosis. Information on the vaginal microbiota can be gathered from the analysis of cervicovaginal fluid, by using the Nugent scoring or the Amsel's criteria, or at the molecular level by investigating the number and type of Lactobacillus species. However, when translating this to the clinical setting, it should be noted that the absence of a Lactobacillus-dominated microbiota does not appear to directly imply a diseased condition or dysbiosis. Nevertheless, the widely documented beneficial role of vaginal Lactobacillus species demonstrates the potential of data on the composition and activity of lactobacilli as biomarkers for vaginal health. The substantiation and further validation of such biomarkers will allow the design of better targeted probiotic strategies

Expression of fluorescent proteins in Lactobacillus rhamnosus to study host–microbe and microbe–microbe interactions

Probiotic Lactobacillus strains are widely used to benefit human and animal health, although the exact mechanisms behind their interactions with the host and the microbiota are largely unknown. Fluorescent tagging of live probiotic cells is an important tool to unravel their modes of action. In this study, the implementation of different heterologously expressed fluorescent proteins for the labelling of the model probiotic strains Lactobacillus rhamnosusGG (gastrointestinal) and Lactobacillus rhamnosusGR-1 (vaginal) was explored. Heterologous expression of mTagBFP2 and mCherry resulted in long-lasting fluorescence of L. rhamnosusGG and GR-1 cells, using the nisin-controlled expression (NICE) system. These novel fluorescent strains were then used to study in vitro aspects of their microbe-microbe and microbe-host interactions. Lactobacillus rhamnosusGG and L. rhamnosusGR-1 expressing mTagBFP2 and mCherry could be visualized in mixed-species biofilms, where they inhibited biofilm formation by Salmonella Typhimurium-gfpmut3 expressing the green fluorescent protein. Likewise, fluorescent L. rhamnosusGG and L. rhamnosusGR-1 were implemented for the visualization of their adhesion patterns to intestinal epithelial cell cultures. The fluorescent L. rhamnosus strains developed in this study can therefore serve as novel tools for the study of probiotic interactions with their environment.status: publishe