Relationship between classic indicators of health behaviour and contraceptive choices in women in Flanders

BACKGROUND

In this study we shed light on ongoing trends in contraceptive use in Flanders (Belgium). Building on the fundamental cause theory and social diffusion of innovation theory, we examine socio-economic gradients in contraceptive use and the relationship to health behaviours.

METHODS

Using the unique and recently collected (2020) ISALA data, we used multinomial logistic regression to model the uptake of contraceptives and its association to educational level and health behaviour (N:4316 women).

RESULTS

Higher educated women, and women with a healthy lifestyle especially, tend to use non-hormonal contraceptives or perceived lower-dosage hormonal contraceptives that are still trustworthy from a medical point of view. Moreover, we identified a potentially vulnerable group in terms of health as our results indicate that women who do not engage in preventive health behaviours are more likely to use no, or no modern, contraceptive method.

DISCUSSION

The fact that higher educated women and women with a healthy lifestyle are less likely to use hormonal contraceptive methods is in line with patient empowerment, as women no longer necessarily follow recommendations by healthcare professionals, and there is a growing demand for naturalness in Western societies.

CONCLUSION

The results of this study can therefore be used to inform policy makers and reproductive healthcare professionals, since up-to-date understanding of women's contraceptive choices is clearly needed in order to develop effective strategies to prevent sexually transmitted infections and unplanned pregnancies, and in which women can take control over their sexuality and fertility in a comfortable and pleasurable way.

A citizen-science-enabled catalogue of the vaginal microbiome and associated factors

Understanding the composition and function of the vaginal microbiome is crucial for reproductive and overall health. Here we established the Isala citizen-science project to analyse the vaginal microbiomes of 3,345 women in Belgium (18-98 years) through self-sampling, 16S amplicon sequencing and extensive questionnaires. The overall vaginal microbiome composition was strongly tied to age, childbirth and menstrual cycle phase. Lactobacillus species dominated 78% of the vaginal samples. Specific bacterial taxa also showed to co-occur in modules based on network correlation analysis. Notably, the module containing Lactobacillus crispatus, Lactobacillus jensenii and Limosilactobacillus taxa was positively linked to oestrogen levels and contraceptive use and negatively linked to childbirth and breastfeeding. Other modules, named after abundant taxa (Gardnerella, Prevotella and Bacteroides), correlated with multiple partners, menopause, menstrual hygiene and contraceptive use. With this resource-rich vaginal microbiome map and associated health, life-course, lifestyle and dietary factors, we provide unique data and insights for follow-up clinical and mechanistic research.

Salivary microbiome of healthy women of reproductive age

IMPORTANCE

The salivary microbiome has been proven to play a crucial role in local and systemic diseases. Moreover, the effects of biological and lifestyle factors such as oral hygiene and smoking on this microbial community have already been explored. However, what was not yet well understood was the natural variation of the saliva microbiome in healthy women and how this is associated with specific use of hormonal contraception and with the number of different sexual partners with whom microbiome exchange is expected regularly. In this paper, we characterized the salivary microbiome of 255 healthy women of reproductive age using an in-depth questionnaire and self-sampling kits. Using the large metadata set, we were able to investigate the associations of several host-related and lifestyle variables with the salivary microbiome profiles. Our study shows a high preservation between individuals.

Lactobacillus isalae sp. nov., isolated from the female reproductive tract

A novel strain of the genus Lactobacillus, named AMBV1719T, was isolated from the vagina of a healthy participant in our large-scale citizen science project on the female microbiome, named Isala. Phylogenetic analysis showed that the 16S rRNA gene of AMBV1719T is most similar to that of Lactobacillus taiwanensis with a sequence similarity of 99.873 %. However, a genome-wide comparison using average nucleotide identity (ANI) revealed that isolate AMBV1719T showed the highest ANI with Lactobacillus paragasseri JCM 5343T, with a value of only 88.17 %. This low ANI value with the most closely related strains known to date indicated that AMBV1719T represents a distinct species. This strain has a limited ability to degrade carbon sources compared to Lactobacillus gasseri, indicating its adaptation to the host. Its genome has a length of 2.12 Mb with a G+C content of 34.8 mol%. We thus propose the name Lactobacillus isalae sp. nov. for this novel species, with AMBV1719T (=LMG 32886T=CECT 30756T) as the type strain.

Spontaneous Riboflavin-Overproducing Limosilactobacillus reuteri for Biofortification of Fermented Foods

Riboflavin-producing lactic acid bacteria represent a promising and cost-effective strategy for food biofortification, but production levels are typically insufficient to support daily human requirements. In this study, we describe the novel human isolate Limosilactobacillus reuteri AMBV339 as a strong food biofortification candidate. This strain shows a high natural riboflavin (vitamin B2) overproduction of 18.36 μg/ml, biomass production up to 6 × 10¹⁰ colony-forming units/ml (in the typical range of model lactobacilli), and pH-lowering capacities to a pH as low as 4.03 in common plant-based (coconut, soy, and oat) and cow milk beverages when cultured up to 72 h at 37°C. These properties were especially pronounced in coconut beverage and butter milk fermentations, and were sustained in co-culture with the model starter Streptococcus thermophilus. Furthermore, L. reuteri AMBV339 grown in laboratory media or in a coconut beverage survived in gastric juice and in a simulated gastrointestinal dialysis model with colon phase (GIDM-colon system) inoculated with fecal material from a healthy volunteer. Passive transport of L. reuteri AMBV339-produced riboflavin occurred in the small intestinal and colon stage of the GIDM system, and active transport via intestinal epithelial Caco-2 monolayers was also demonstrated. L. reuteri AMBV339 did not cause fecal microbiome perturbations in the GIDM-colon system and inhibited enteric bacterial pathogens in vitro. Taken together, our data suggests that L. reuteri AMBV339 represents a promising candidate to provide riboflavin fortification of plant-based and dairy foods, and has a high application potential in the human gastrointestinal tract.

Microbial enrichment and storage for metagenomics of vaginal, skin, and saliva samples

Few validated protocols are available for large-scale collection, storage, and analysis of microbiome samples from the vagina, skin, and mouth. To prepare for a large-scale study on the female microbiome by remote self-sampling, we investigated the impact of sample collection, storage, and host DNA depletion on microbiome profiling. Vaginal, skin, and saliva samples were analyzed using 16S rRNA gene amplicon and metagenomic shotgun sequencing, and qPCR. Of the two tested storage buffers, the eNAT buffer could keep the microbial composition stable during various conditions. All three tested host DNA-depletion approaches showed a bias against Gram-negative taxa. However, using the HostZERO Microbial DNA and QIAamp DNA Microbiome kits, samples still clustered according to body site and not by depletion approach. Therefore, our study showed the effectiveness of these methods in depleting host DNA. Yet, a suitable approach is recommended for each habitat studied based on microbial composition.

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Lysis buffer keeps the microbial composition stable during various storage conditions

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Host DNA depletion introduces a larger bias toward Gram-negative taxa

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The HostZERO Microbial DNA kit performed best in human DNA depletion for metagenomics

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Body site-specific approach based on microbial composition is needed to minimize bias

At the Interface of Life and Death: Post-mortem and Other Applications of Vaginal, Skin, and Salivary Microbiome Analysis in Forensics

Microbial forensics represents a promising tool to strengthen traditional forensic investigative methods and fill related knowledge gaps. Large-scale microbiome studies indicate that microbial fingerprinting can assist forensics in areas such as trace evidence, source tracking, geolocation, and circumstances of death. Nevertheless, the majority of forensic microbiome studies focus on soil and internal organ samples, whereas the microbiome of skin, mouth, and especially vaginal samples that are routinely collected in sexual assault and femicide cases remain underexplored. This review discusses the current and emerging insights into vaginal, skin, and salivary microbiome-modulating factors during life (e.g., lifestyle and health status) and after death (e.g., environmental influences and post-mortem interval) based on next-generation sequencing. We specifically highlight the key aspects of female reproductive tract, skin, and mouth microbiome samples relevant in forensics. To fill the current knowledge gaps, future research should focus on the degree to which the post-mortem succession rate and profiles of vaginal, skin, and saliva microbiota are sensitive to abiotic and biotic factors, presence or absence of oxygen and other gases, and the nutrient richness of the environment. Application of this microbiome-related knowledge could provide valuable complementary data to strengthen forensic cases, for example, to shed light on the circumstances surrounding death with (post-mortem) microbial fingerprinting. Overall, this review synthesizes the present knowledge and aims to provide a framework to adequately comprehend the hurdles and potential application of vaginal, skin, and salivary post-mortem microbiomes in forensic investigations.