The Effect of L. crispatus on HPV Infection and Vaginal Microbiome Balance
The Effect of L. crispatus on HPV Infection and Vaginal Microbiome Balance
Mobina Rezaeijou,1,*Bita Zandi,2Fatemeh Roozbahani,3
1. Islamic Azad University, Tehran Medical Branch 2. Department of Microbiology, School of Medicine،Golestan University of Medical Sciences 3. Department of Medical Microbiology and Virology, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran.
Introduction: The vaginal microbiome consists of diverse microorganisms known as vaginal flora, which play an important role in the health of women and their babies. Studies of the human microbiome have identified four main branches of dominant bacteria in the vaginal flora: Firmicutes, Proteobacteria, Actinobacteria, and Bacteroidetes. The most important family of Firmicutes is Lactobacillus, whose dominant bacterial species compete against other pathogens by reducing the pH of the environment, producing bacteriocins, lactic acid, and hydrogen peroxide, and helping regulate the immune response through their metabolic activities. The composition of the vaginal microbiota is influenced by various factors, such as age, menstruation, hormonal fluctuations, sexual behaviors, and the use of drugs, such as probiotics and antibiotics. Disruption of microbiome balance can lead to dysbiosis and diseases such as bacterial vaginosis (BV), vulvovaginal candidiasis (VVC), and sexually transmitted diseases, including human papilloma virus (HPV) infection. Persistent high-risk HPV infection increases the risk of cervical cancer, which is the fourth most common cancer among women worldwide and causes 342,000 deaths in 2020, according to the World Health Organization. This study aimed to investigate the effect of L. crispatus as a probiotic to improve the vaginal microbiome during HPV infection.
Methods: To analyze the structure of the vaginal microbial community, researchers collected samples from the cervix and used next-generation sequencing (NGS) to analyze the 16S rRNA genes of the V3-V4 variable region. The researchers also aimed to establish a relationship between the diversity of the vaginal microbiome and HPV infection. Real-time quantitative fluorescence PCR was used to detect HPV type and viral load before and after treatment with Lactobacillus probiotic.
Results: The analysis of vaginal flora bacteria diversity showed that anaerobic pathogenic vaginal bacteria at the genus level, including Prevotella, Gardnerella, and Sneathia, were more abundant in HPV infection, while lactobacilli were less frequent. In contrast, treatment with probiotics showed that L. crispatus was able to improve the normal flora of the vagina by inhibiting the growth of pathogenic bacteria, regulating the immune system, and increasing the abundance of lactobacilli. The researchers also found that the use of L. crispatus probiotic significantly reduced viral load, inflammation, and improved vaginal cytology due to its antiviral and metabolic activities.
Conclusion: According to the obtained results and the research related to the vaginal microbiome's ability in HPV infection, the use of Lactobacillus probiotics can significantly impact the rate of cytological recovery, vaginal inflammation, and reduce the HPV viral load and the balance of the vaginal microbiome. However, further extensive research is still needed for researchers to achieve more effective treatments with the aid of vaginal probiotics.