Community Structure and Ecological Network's Changes of Vaginal Microbiome in Women Right After Delivery

Alterations of the paired maternal vaginal microbiome and neonatal meconium microbiome in vulvovaginal candidiasis positive pregnant women

Background

Women with vulvovaginal candidiasis (VVC) are known to experience vaginal microbial dysbiosis. However, the dynamic alterations of the vaginal microbiome in pregnant women with VVC and its effect on neonatal gut microbiome remain unclear. This study aims to characterize the vaginal microbiome in pregnant women with VVC and its impact on their offspring's meconium microbiome.

Methods

Forty-four pregnant women, including 17 with VVC (VVC group) and 27 healthy controls (HC group), along with their 44 offspring, were enrolled in this study. Maternal vaginal samples were collected during the pre- and post-delivery phases. Meconium samples from their newborns were also obtained. Microbial communities were characterized using 16S rRNA sequencing.

Results

The vaginal microbiome of healthy pregnant women was predominantly composed of the genus Lactobacillus. The Bray-Curtis dissimilarity index indicated significant alterations in the vaginal microbiome of the VVC group, with a notable decrease in Lactobacillus and significant increases in Delftia, Burkholderia during both the pre- and post-delivery phases compared to the HC group. Additionally, the neonatal meconium microbiome exhibited significant differences between the VVC and HC groups, with L. salivarius and L. helveticus significantly decreased and Delftia significantly increased in the VVC group. Similar trends in microbial variation were observed across maternal and neonatal microbiomes, indicating intergenerational concordance associated with VVC.

Conclusion

VVC alters the microbiota of both pregnant women and their neonates at birth, suggesting a form of microbial inheritance. These findings underscore the distinctive characteristics of the vaginal microbiome associated with VVC and its potential impact on the formation of early-life gut microbiome.

Unique microbial diversity, community composition, and networks among Pacific Islander endocervical and vaginal microbiomes with and without Chlamydia trachomatis infection in Fiji

IMPORTANCE

Chlamydia trachomatis (Ct) is the most common sexually transmitted bacterium globally. Endocervical and vaginal microbiome interactions are rarely examined within the context of Ct or among vulnerable populations. We evaluated 258 vaginal and 92 paired endocervical samples from Fijian women using metagenomic shotgun sequencing. Over 37% of the microbiomes could not be classified into sub-community state types (subCSTs). We, therefore, developed subCSTs IV-D0, IV-D1, IV-D2, and IV-E-dominated primarily by Gardnerella vaginalis-to improve classification. Among paired microbiomes, the endocervix had a significantly higher alpha diversity and, independently, higher diversity for high-risk human papilloma virus (HPV) genotypes compared to low-risk and no HPV. Ct-infected endocervical networks had smaller clusters without interactions with potentially beneficial Lactobacillus spp. Overall, these data suggest that G. vaginalis may generate polymicrobial biofilms that predispose to and/or promote Ct and possibly HPV persistence and pathogenicity. Our findings expand on the existing repertoire of endocervical and vaginal microbiomes and fill in knowledge gaps regarding Pacific Islanders.

Association between vaginal microbiome alteration and povidone iodine use during delivery

BACKGROUND

The vaginal microbiome is a dynamic community of microorganisms in the vagina. Its alteration may be influenced by multiple factors, including gestational status, menstrual cycle, sexual intercourse, hormone levels, hormonal contraceptives, and vaginal drug administration. Povidone iodine has been used before delivery to reduce infection that may be caused by the ascendance of pathogenic and opportunistic bacteria from the vagina to the uterus. This study aimed to elucidate the impact of povidone iodine use during delivery on the vaginal microbiome.

METHODS

This study enrolled a total of 67 women from maternity services in three hospitals. During the delivery process, we have applied povidone iodine in three doses such as low dose, medium dose, and high dose based on the amount of povidone iodine administered, thus, we studied the three groups of women based on the doses applied. Vaginal swab samples were collected both before and immediately after delivery, and the microbial communities were characterized using 16 S rRNA sequencing. The identification of differentially abundant microbial taxa was performed using ZicoSeq software.

RESULTS

Before delivery, the vaginal microbiome was dominated by the genus Lactobacillus, with different percentage observed (86.06%, 85.24%, and 73.42% for the low, medium, and high dose groups, respectively). After delivery, the vaginal microbial community was restructured, with a significant decrease in the relative abundance of Lactobacillus in all three groups (68.06%, 50.08%, and 25.89%), and a significant increase in alpha diversity across all 3 groups (P < 0.01). Furthermore, as the dose of povidone iodine used during delivery increased, there was a corresponding decrease in the relative abundance of Lactobacillus (P < 0.01). Contrary, there was an increase in microbial diversity and the relative abundances of Pseudomonas (0.13%, 0.26%, and 13.04%, P < 0.01) and Ralstonia (0.01%, 0.02%, and 16.07%, P < 0.01) across the groups. Notably, some functional metabolic pathways related to sugar degradation were observed to have significant change with increasing use of povidone iodine.

CONCLUSION

Povidone iodine was associated with the vaginal microbiome alterations after parturition, and its significant change was associated to the dosage of povidone iodine administered. The escalation in iodine dosage was linked to a decrease in Lactobacilli abundance, and elevated prevalence of Pseudomonas and Ralstonia. There is a need for longitudinal studies to clearly understanding the effect of povidone iodine use on maternal and infant microbiome.