Comparative Analysis of Lactobacillus gasseri and Lactobacillus crispatus Isolated From Human Urogenital and Gastrointestinal Tracts

Purified L-glutaminase effects against multidrug-resistant Pseudomonas aeruginosa in experimental vaginosis model: An immunological and histopathological observation

The antimicrobial activity of crude and purified L-glutaminase (EC 3.5.1.2), obtained from Lactobacillus gasseri, was evaluated against multidrug-resistant Pseudomonas aeruginosa in the in vivo vaginosis condition. The L-glutaminase possessed significant antimicrobial and anti-biofilm formation activity against multi-drug resistance P. aeruginosa, which were confirmed in the BALBc rat vaginosis model, together with its effects on the immunological and histopathological aspects. The untreated animals showed heavy vaginitis, characterized by sub-epithelial edema and infiltration of mononuclear leukocytes, perivascular heavy inflammatory cells infiltration in the vaginal tissue, and moderate stromal edema. However, the L-glutaminase treatment exhibited no changes in vaginal tissue structure with normal appearance of the epithelium and lamina propria with marked repair of the vaginal section when compared with normal, uninfected, control group A. The immunomodulatory actions of the L-glutaminase were confirmed by observance of higher concentrations of tumor necrosis factor-γ (TNF-γ), and interleukin -12 (IL-12) in treated animals, while the interleukin-10 (IL-10) was higher in the infected, untreated animals' sera samples. Therefore, the L-glutaminase showed corrective and healing actions, which were observed through histopathological observations of the vaginal tissue. The investigations led to imply that L-glutaminase may have the potential to be an effective antimicrobial agent for preventing and inhibiting bacterial growth, as well as inhibiting the biofilm formation in the P. aeruginosa-originated vaginosis. The observations may be of promising value for future clinical use.

Disclosing α-lactalbumin impact on the intestinal and vaginal microbiota of women suffering from polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is one of the most widespread endocrinopathy affecting women of reproductive age with detrimental effects on life quality and health. Among several mechanisms involved in its aetiopathogenesis, recent studies have also postulated the involvement of the vaginal and intestinal microbiota in the development of this disorder. In this study, an accurate insight into the microbial changes associated with PCOS was performed through a pooled-analysis highlighting that this syndrome is characterized by intestinal and vaginal dysbiosis with a reduction of beneficial microorganisms and a higher proportion of potential pathogens. Based on this observation, we evaluated the ability of a milk-derived protein exerting positive outcomes in the management of PCOS, that is, α-lactalbumin (α-LA), to recover PCOS-related dysbiosis. In vitro experiments revealed that this protein improved the growth performances of members of two health-promoting bacterial genera, that is, Bifidobacterium and Lactobacillus, depleted in both intestinal and vaginal microbiota of PCOS-affected women. In addition, α-LA modulated the taxonomic composition and growth performances of the microbial players of the complex intestinal and vaginal microbiota. Finally, an in vivo pilot study further corroborated these observations. The oral administration of α-LA for 30 days to women with PCOS revealed that this protein may have a role in favouring the growth of health-promoting bacteria yet limiting the proliferation of potential pathogens. Overall, our results could pave the way to the use of α-LA as a valid compound with 'prebiotic effects' to limit/restore the PCOS-related intestinal and vaginal dysbiosis.

Pharmabiotic/phytobiotic formulas approach and their intravaginal effect on different parameters

Postpartum reproductive infections in cows generate significant economic losses. The use of lactic acid bacteria in animal health is an alternative tool to avoid antibiotic therapy in the prevention/treatment of bovine reproductive infections. In previous studies, 6 lactic bacteria from bovine mammary glands and vagina with beneficial, safe and technological characteristics were selected, and included in probiotic/phytobiotic formulas (combined with Malva and Lapacho extracts). In this work, probiotic and phytobiotic formulations were designed and their long-term viability determined. They were administered intravaginally to 30 females pregnant bovine pre and postpartum. The modification of the native microbiota and permanence/colonization of cultivable bacteria was evaluated, and also the safety of the designed products through the application of nutritional, clinical, hematological and biochemical parameters. The microorganisms maintained their viability up to 9 months at refrigeration temperature. The number of cultivable bacteria showed different pattern: total aerobic mesophylls increased slightly in all experimental groups, while Enterobacteriaceae increased after delivery, except in beneficial acid lactic bacteria + vegetable extract cows. Control and vegetable extract females showed the highest numbers of Enterobacteriaceae at the end of the trial (30 days postpartum). The number of lactic acid bacteria increased significantly in all the groups between 15 days pre and postpartum. The different parameters evaluated demonstrate the safety and harmlessness of the designed formulas, without producing local and systemic adverse effects in the cows.

Isolation of lactic acid bacteria from the reproductive tract of mares as potentially beneficial strains to prevent equine endometritis

Endometritis, the inflammation of the endometrium, is the leading cause of subfertility in mares, and therefore responsible for major economic losses in the horse industry worldwide. It is generally treated with uterine lavages combined with ecbolic agents and local or systemic antibiotics. However, since antibiotic overuse has been associated with antimicrobial resistance in mares with persistent endometritis, new prevention and treatment alternatives are needed. One such alternative could be the use of probiotic lactic acid bacteria (LAB) isolated from the host. Thanks to their species specificity, resident microbiota may restore ecological equilibrium within the host, and therefore, help prevent infections and improve physiological functions. In the present study, 257 bacterial strains were isolated from 77 healthy mares, and 88.76% (n = 228) of them were phenotypically classified as LAB. Within this group, 65.79% were able to inhibit at least one strain from each of the genera that most commonly cause equine endometritis (Streptococcus equi subsp. zooepidemicus, Escherichia coli, and Staphylococcus spp.). Five strains (RCE11, RCE20, RCE91, RCE99, and RCE167) were selected on the basis of their beneficial properties: ability to autoaggregate and adhere to equine epithelial cells, high inhibition of and co-aggregation with all the bacteria isolated from clinical cases of endometritis evaluated, and negative co-inhibition between one another. All five were finally identified as Enterococcus spp., namely E. faecium (two strains), E. hirae (two strains), and E. gallinarum (one strain). Further studies will assess their safety and biotechnological potential for the design of a multi-strain probiotic formula to prevent equine endometritis.

A molecular view on the interference established between vaginal Lactobacilli and pathogenic Candida species: Challenges and opportunities for the development of new therapies

Vaginal infectious diseases caused by viruses and bacteria have been linked to the occurrence of dysbiosis, that is, a reduction in the abundance of the normally dominating vaginal Lactobacillus species. Mucosal infections in the vagina and/or vulva caused by Candida species, usually known as vulvovaginal candidiasis (or VVC), are among the leading causes of diseases in the vaginal tract. The existence of a clear link between the occurrence of dysbiosis and the development of VVC is still unclear, although multiple observations point in that direction. Based on the idea that vaginal health is linked to a microbiota dominated by lactobacilli, several probiotics have been used in management of VVC, either alone or in combination with antifungals, having obtained different degrees of success. In most cases, the undertaken trials resorted to lactobacilli species other than those indigenous to the vaginal tract, although in vitro these vaginal species were shown to reduce growth, viability and virulence of Candida. In this paper we overview the role of lactobacilli and Candida in the vaginal micro- and myco-biomes, while discussing the results obtained in what concerns the establishment of interference mechanisms in vivo and the environmental factors that could determine that. We also overview the molecular mechanisms by which lactobacilli species have been shown to inhibit pathophysiology of Candida, including the description of the genes and pathways determining their ability to thrive in the presence of each other. In a time where concerns are increasing with the emergence of antifungal resistance and the slow pace of discovery of new antifungals, a thorough understanding of the molecular mechanisms underneath the anti-Candida effect prompted by vaginal lactobacilli is of utmost importance to assure a knowledge-based design of what can be a new generation of pharmaceuticals, eventually focusing therapeutic targets other than the usual ones.

Anti-microbial efficacy of L-glutaminase (EC 3.5.1.2) against multidrug-resistant Pseudomonas aeruginosa infection

The aims of this study were isolation-purification and characterization of L-glutaminase from L. gasseri BRLHM clinical isolates and investigation of its efficiency as an antimicrobial agent against multidrug-resistant P. aeruginosa. The MICs of L-glutaminase and gentamicin reference were evaluated by the well-diffusion method. The biofilm on the IUD contraceptive was visualized using atomic force microscopy (AFM) image analyses. The purified L-glutaminase possessed significant antimicrobial activity against P. aeruginosa isolates (p < 0.05), and the antibiofilm formation activity of the purified L-glutaminase was stronger than the antibiofilm activity of the referral standard drug, gentamicin (P < 0.05), which were checked by the inhibition of the biofilm formation on the IUD contraceptive device. Investigations indicated that L-glutaminase may have a crucial role in future clinical applications.

Effect of enzyme-assisted fermentation on quality, safety, and microbial community of black soldier fly larvae (Hermetia illucens L.) as a novel protein source

Considering the significance and scarcity of quality protein, this study aims to obtain a novel safe protein source through fermenting the black soldier fly larvae (BSFL). Lactobacillus crispatus M1027 and Pichia kudriavzevii DHX19 were added as starters together with neutral protease for enzymolysis during fermentation. The results showed that the low pH value (from 6.60 to 3.99), generated by lactic acid accumulation, created an environment where the pathogen could hardly grow. During fermentation, the flavor compound ethyl acetate content reached up to 406.55 mg/L, and the melanization was effectively inhibited by the starters. The increase of trichloroacetic acid-soluble protein content (from 8.73 % to 17.96 %) contributed to improving the absorbability of product by animals after feeding. Notably, the contents of detrimental substances, including total volatile basic nitrogen and histamine, were both below specified limits after fermentation. Simultaneously, the malonic dialdehyde content remained stable during fermentation. Relative abundance of Lactobacillus and Pichia gradually increased and finally dominated in the culture during fermentation, accompanied by pathogens decline below detection limit (1.0 Log cfu/g). Moreover, there was a close relationship between the dynamics of physicochemical indices and microbial succession. Overall, our studies explored a new process to ferment the BSFL paste which would improve the quality and safety of fermented BSFL paste. This research provided theoretical support for fermented insect as a novel protein source.

A novel approach for exploring the regional features of vaginal fluids based on microbial relative abundance and alpha diversity

Vaginal fluids are one of the most common biological samples in forensic sexual assault cases, and their characterization is vital to narrow the scope of investigation. Presently, approaches for identifying vaginal fluids in different regions are not only rare but also have certain limitations. However, the microbiome has shown the potential to identify the source of body fluids and reveal the characteristics of individuals. In this study, 16S rRNA gene high-throughput sequencing was used to characterize the vaginal microbial community from three regions, Sichuan, Hainan and Hunan. In addition, data on relative abundance and alpha diversity were used to construct a random forest model. The results revealed that the dominant genera in the three regions were Lactobacillus, followed by Gardnerella. In addition, Ureaplasma, Nitrospira, Nocardiodes, Veillonella and g-norank-f-Vicinamibacteraceae were significantly enriched genera in Sichuan, llumatobacter was enriched in Hainan, and Pseudomonas was enriched in Hunan. The random forest classifier based on combined data on relative abundance and alpha diversity had a good ability to distinguish vaginal fluids with similar dominant microbial compositions in the three regions. The study suggests that combining high-throughput sequencing data with machine learning models has good potential for application in the biogeographic inference of vaginal fluids.

The core genome evolution of Lactobacillus crispatus as a driving force for niche competition in the human vaginal tract

The lower female reproductive tract is notoriously dominated by Lactobacillus species, among which Lactobacillus crispatus emerges for its protective and health-promoting activities. Although previous comparative genome analyses highlighted genetic and phenotypic diversity within the L. crispatus species, most studies have focused on the presence/absence of accessory genes. Here, we investigated the variation at the single nucleotide level within protein-encoding genes shared across a human-derived L. crispatus strain selection, which includes 200 currently available human-derived L. crispatus genomes as well as 41 chromosome sequences of such taxon that have been decoded in the framework of this study. Such data clearly pointed out the presence of intra-species micro-diversities that could have evolutionary significance contributing to phenotypical diversification by affecting protein domains. Specifically, two single nucleotide variations in the type II pullulanase gene sequence led to specific amino acid substitutions, possibly explaining the substantial differences in the growth performances and competition abilities observed in a multi-strain bioreactor culture simulating the vaginal environment. Accordingly, L. crispatus strains display different growth performances, suggesting that the colonisation and stable persistence in the female reproductive tract between the members of this taxon is highly variable.

Exploring the genotypic and phenotypic differences distinguishing Lactobacillus jensenii and Lactobacillus mulieris

Lactobacillus crispatus, Lactobacillus gasseri, Lactobacillus iners, and Lactobacillus jensenii are dominant species of the urogenital microbiota. Prior studies suggest that these Lactobacillus species play a significant role in the urobiome of healthy females. In our prior genomic analysis of all publicly available L. jensenii and Lactobacillus mulieris genomes at the time (n = 43), we identified genes unique to these two closely related species. This motivated our further exploration here into their genotypic differences as well as into their phenotypic differences. First, we expanded genome sequence representatives of both species to 61 strains, including publicly available strains and nine new strains sequenced here. Genomic analyses conducted include phylogenetics of the core genome as well as biosynthetic gene cluster analysis and metabolic pathway analyses. Urinary strains of both species were assayed for their ability to utilize four simple carbohydrates. We found that L. jensenii strains can efficiently catabolize maltose, trehalose, and glucose, but not ribose, and L. mulieris strains can utilize maltose and glucose, but not trehalose and ribose. Metabolic pathway analysis clearly shows the lack of treB within L. mulieris strains, indicative of its inability to catabolize external sources of trehalose. While genotypic and phenotypic observations provide insight into the differences between these two species, we did not find any association with urinary symptom status. Through this genomic and phenotypic investigation, we identify markers that can be leveraged to clearly distinguish these two species in investigations of the female urogenital microbiota. IMPORTANCE We have expanded upon our prior genomic analysis of L. jensenii and L. mulieris strains, including nine new genome sequences. Our bioinformatic analysis finds that L. jensenii and L. mulieris cannot be distinguished by short-read 16S rRNA gene sequencing alone. Thus, to discriminate between these two species, future studies of the female urogenital microbiome should employ metagenomic sequencing and/or sequence species-specific genes, such as those identified here. Our bioinformatic examination also confirmed our prior observations of differences between the two species related to genes associated with carbohydrate utilization, which we tested here. We found that the transport and utilization of trehalose are key distinguishing traits of L. jensenii, which is further supported by our metabolic pathway analysis. In contrast with other urinary Lactobacillus species, we did not find strong evidence for either species, nor particular genotypes, to be associated with lower urinary tract symptoms (or the lack thereof).

Immunomodulatory effects of live and pasteurized Lactobacillus crispatus strain RIGLD-1 on Helicobacter pylori-triggered inflammation in gastric epithelial cells in vitro

BACKGROUND

Helicobacter pylori infection is considered as the major risk factor for gastric adenocarcinoma. Today, the increasing emergence of antibiotic-resistant strains has drastically decreased the eradication rate of H. pylori infection. This study was aimed to investigate the inhibitory and modulatory effects of live and pasteurized Lactobacillus crispatus strain RIGLD-1 on H. pylori adhesion, invasion, and inflammatory response in AGS cell line.

METHODS AND RESULTS

The probiotic potential and properties of L. crispatus were evaluated using several functional and safety tests. Cell viability of AGS cells exposed to varying concentrations of live and pasteurized L. crispatus was assessed by MTT assay. The adhesion and invasion abilities of H. pylori exposed to either live or pasteurized L. crispatus were examined by gentamycin protection assay. The mRNA expression of IL-1β, IL-6, IL-8, TNF-α, IL-10, and TGF-ß genes was determined by RT-qPCR from coinfected AGS cells. ELISA was used for the detection of IL-8 secretion from treated cells. Both live and pasteurized L. crispatus significantly decreased H. pylori adhesion/invasion to AGS cells. In addition, both live and pasteurized L. crispatus modulated H. pylori-induced inflammation by downregulating the mRNA expression of IL-1β, IL-6, IL-8, and TNF-α and upregulating the expression of IL-10, and TGF-ß cytokines in AGS cells. Furthermore, H. pylori-induced IL-8 production was dramatically decreased after treatment with live and pasteurized L. crispatus.

CONCLUSIONS

In conclusion, our findings demonstrated that live and pasteurized L. crispatus strain RIGLD-1 are safe, and could be suggested as a potential probiotic candidate against H. pylori colonization and inflammation.

Orally administrated Lactobacillus gasseri TM13 and Lactobacillus crispatus LG55 can restore the vaginal health of patients recovering from bacterial vaginosis

Bacterial vaginosis (BV) is a common infection of the lower genital tract with a vaginal microbiome dysbiosis caused by decreasing of lactobacilli. Previous studies suggested that supplementation with live Lactobacillus may benefit the recovery of BV, however, the outcomes vary in people from different regions. Herein, we aim to evaluate the effectiveness of oral Chinese-origin Lactobacillus with adjuvant metronidazole (MET) on treating Chinese BV patients. In total, 67 Chinese women with BV were enrolled in this parallel controlled trial and randomly assigned to two study groups: a control group treated with MET vaginal suppositories for 7 days and a probiotic group treated with oral Lactobacillus gasseri TM13 and Lactobacillus crispatus LG55 as an adjuvant to MET for 30 days. By comparing the participants with Nugent Scores ≥ 7 and < 7 on days 14, 30, and 90, we found that oral administration of probiotics did not improve BV cure rates (72.73% and 84.00% at day 14, 57.14% and 60.00% at day 30, 32.14% and 48.39% at day 90 for probiotic and control group respectively). However, the probiotics were effective in restoring vaginal health after cure by showing higher proportion of participants with Nugent Scores < 4 in the probiotic group compared to the control group (87.50% and 71.43% on day 14, 93.75% and 88.89% on day 30, and 77.78% and 66.67% on day 90). The relative abundance of the probiotic strains was significantly increased in the intestinal microbiome of the probiotic group compared to the control group at day 14, but no significance was detected after 30 and 90 days. Also, the probiotics were not detected in vaginal microbiome, suggesting that L. gasseri TM13 and L. crispatus LG55 mainly acted through the intestine. A higher abundance of Prevotella timonensis at baseline was significantly associated with long-term cure failure of BV and greatly contributed to the enrichment of the lipid IVA synthesis pathway, which could aggravate inflammation response. To sum up, L. gasseri TM13 and L. crispatus LG55 can restore the vaginal health of patients recovering from BV, and individualized intervention mode should be developed to restore the vaginal health of patients recovering from BV.

Clinical trial registration

https://classic.clinicaltrials.gov/ct2/show/, identifier NCT04771728.

Probiotic characteristics of Lactobacillus gasseri TF08-1: A cholesterol-lowering bacterium, isolated from human gut

Lactobacillus contribute to maintain the human healthy and use for nutritional additives as probiotics. In this study, a cholesterol-lowering bacterium, Lactobacillus gasseri TF08-1, was isolated from the feces of a healthy adolescent, and its probiotic potentials were evaluated through genomic mining and in vitro test. The assembled draft genome comprised of 1,974,590 bp and was predicted total of 1,940 CDSs. The annotation of the genome revealed that L. gasseri TF08-1 harbored abundant categories of functional genes in metabolic and information processing. Moreover, strain TF08-1 has capacity to utilize D-Glucose, Sucrose, D-Maltose, Salicin, D-Xylose, D-Cellobiose, D-Mannose, and D-Trehalose, as the carbon source. The safety assessment showed strain TF08-1 contained few antibiotic resistance genes and virulence factors and was only resistant to 2 antibiotics detected by antimicrobial susceptibility test. A high bile salt hydrolase activity was found and a cholesterol-reducing effect was determined in vitro, which the result showed a remarkable cholesterol removal capability of L. gasseri TF08-1 with an efficiency of 84.40 %. This study demonstrated that the strain showed great capability of exopolysaccharide production, and tolerance to acid and bile salt. Therefore, these results indicate that L. gasseri TF08-1 can be considered as a safe candidate for probiotic, especially its potential in biotherapeutic for metabolic diseases.

In Vitro Assessment of Lactobacillus crispatus UBLCp01, Lactobacillus gasseri UBLG36, and Lactobacillus johnsonii UBLJ01 as a Potential Vaginal Probiotic Candidate

In this study, Lactobacillus crispatus UBLCp01, Lactobacillus gasseri UBLG36, and Lactobacillus johnsonii UBLJ01 isolated from the vagina of healthy reproductive age Indian women were screened for beneficial probiotic properties. These strains showed the ability to survive acidic and simulated vaginal fluid conditions and could adhere to mucin. Lact. gasseri UBLG36, and Lact. johnsonii UBLJ01 produced D- and L-lactic acid, whereas Lact. crispatus UBLCp01 produced hydrogen peroxide and D- and L-lactic acid. All strains inhibited the growth of pathogens (Escherichia coli, Gardnerella vaginalis, Proteus mirabilis, and Candida albicans) and were capable of co-aggregating with them with varying degrees. Strains secreted exopolysaccharides and formed biofilms under in vitro conditions. Safety assessment showed that these strains had a usual antibiotic susceptibility profile, did not produce hemolysins, gelatinases, and mucin degrading enzymes. Based on strain characteristics and beneficial properties, we believe that these strains are promising candidates for human trials to confirm their ability to prevent/treat vaginal dysbiosis and maintain a healthy vaginal eco-system.

Antimicrobial and immunoregulatory effects of Lactobacillus delbrueckii 45E against genitourinary pathogens

BACKGROUND

Lactobacilli are essential microbiota that maintain a healthy, balanced vaginal environment. Vaginitis is a common infection in women during their reproductive years. Many factors are associated with vaginitis; one of them is the imbalance of microbiota in the vaginal environment. This study aimed to evaluate the antimicrobial properties of Lactobacillus delbrueckii 45E (Ld45E) against several species of bacteria, namely, Group B Streptococcus (GBS), Escherichia coli, Klebsiella spp., and Candida parapsilosis, as well as to determine the concentration of interleukin-17 (IL-17) in the presence of Ld45E.

METHODS

The probiotic characteristics of Ld45E were evaluated by examining its morphology, pH tolerance, adhesive ability onto HeLa cells, hemolytic activity, antibiotic susceptibility, and autoaggregation ability. Then, the antimicrobial activity of Ld45E was determined using Ld45E culture, cell-free supernatant, and crude bacteriocin solution. Co-aggregation and competition ability assays against various pathogens were conducted. The immunoregulatory effects of Ld45E were analyzed by measuring the proinflammatory cytokine IL-17. A p-value less than 0.05 was considered statistical significance.

RESULTS

Ld45E is 3-5 mm in diameter and round with a flat-shaped colony. pH 4 and 4.5 were the most favorable range for Ld45E growth within 12 h of incubation. Ld45E showed a strong adhesion ability onto HeLa cells (86%) and negative hemolytic activities. Ld45E was also sensitive to ceftriaxone, cefuroxime, ciprofloxacin, and doxycycline. We found that it had a good autoaggregation ability of 80%. Regarding antagonistic properties, Ld45E culture showed strong antimicrobial activity against GBS, E. coli, and Klebsiella spp. but only a moderate effect on C. parapsilosis. Cell-free supernatant of Ld45E exerted the most potent inhibitory effects at 40 °C against all genital pathogens, whereas bacteriocin showed a robust inhibition at 37 °C and 40 °C. The highest co-aggregation affinity was observed with GBS (81%) and E. coli (40%). Competition ability against the adhesion of GBS (80%), E. coli (76%), Klebsiella (72%), and C. parapsilosis (58%) was found. Ld45E was able to reduce the induction of the proinflammatory protein IL-17.

CONCLUSIONS

Ld45E possessed antimicrobial and immunoregulatory properties, with better cell-on-cell activity than supernatant activity. Thus, Ld45E is a potential probiotic candidate for adjunct therapy to address vaginal infections.

Bioinformatics and its role in the study of the evolution and probiotic potential of lactic acid bacteria

Due to their numerous well-established applications in the food industry, there have been many studies regarding the adaptation and evolution of lactic acid bacteria (LAB) in a wide variety of hosts and environments. Progress in sequencing technology and continual decreases in its costs have led to the availability of LAB genome sequence data. Bioinformatics has been central to the extraction of valuable information from these raw genome sequence data. This paper presents the roles of bioinformatics tools and databases in understanding the adaptation and evolution of LAB, as well as the bioinformatics methods used in the initial screening of LAB for probiotic potential. Moreover, the advantages, challenges, and limitations of employing bioinformatics for these purposes are discussed.

Commensal Lactobacilli Metabolically Contribute to Cervical Epithelial Homeostasis in a Species-Specific Manner

In reproductive-age women, the vaginal microbiome is typically dominated by one or a few Lactobacillus species, including Lactobacillus crispatus, Lactobacillus iners, Lactobacillus paragasseri, Lactobacillus mulieris, and Lactobaccillus crispatus, has been associated with optimal cervicovaginal health; however, much is still unknown about how other lactobacilli metabolically contribute to cervicovaginal health. We hypothesized that metabolites of each Lactobacillus species differ and uniquely contribute to health and homeostasis. To address this hypothesis, we utilized a human three-dimensional (3D) cervical epithelial cell model in conjunction with genomics analyses and untargeted metabolomics to determine the metabolic contributions of less-studied vaginal lactobacilli-L. iners, L. paragasseri, and L. mulieris. Our study validated that vaginal lactobacilli exhibit a close phylogenetic relationship. Genomic findings from publicly available strains and those used in our study indicated that L. iners is metabolically distinct from other species of lactobacilli, likely due to a reduced genome size. Lactobacilli and mock controls were distinguishable based on global metabolic profiles. We identified 95 significantly altered metabolites (P < 0.05) between individual lactobacilli and mock controls. Metabolites related to amino acid metabolism were shared among the lactobacilli. N-Acetylated amino acids with potential antimicrobial properties were significantly elevated in a species-specific manner. L. paragasseri and L. iners shared aromatic, but not carbohydrate-derived, lactic acid metabolites with potential antimicrobial properties that may contribute to homeostasis of the cervicovaginal environment. Additionally, L. iners uniquely altered lipid metabolism, which may be a sign of adaptation to the cervicovaginal niche. Overall, these findings further elucidate the metabolic contributions of three key vaginal Lactobacillus species in gynecological health. IMPORTANCE Lactobacillus species contribute to cervicovaginal health by their production of lactic acid and other antimicrobial compounds. Yet, much is still unknown regarding the metabolic potential of lesser-studied but common vaginal lactobacilli. Here, we used untargeted metabolomics coupled with our 3D cervical epithelial cell model to identify metabolic differences among vaginal Lactobacillus species (Lactobacillus iners, Lactobacillus paragasseri, and Lactobacillus mulieris) and how those differences related to maintaining homeostasis of the cervical epithelium. Human 3D cell models are essential tools for studying host-bacteria interactions and reducing confounding factors inherent in clinical studies. Therefore, these unique models allowed us to decipher the putative lactobacilli mechanisms that contribute to their roles in health or disease. Metabolic analyses revealed distinct profiles of each Lactobacillus species but also shared metabolic contributions associated with antimicrobial activity: amino acid metabolism, N-acetylated amino acids, and aromatic lactic acids. These patterns provided validation of metabolites associated with health in clinical studies and provided novel targets, including immunomodulatory and antimicrobial metabolites, for postbiotic therapies.

Female reproductive tract-organ axes

The female reproductive tract (FRT) and remote/versatile organs in the body share bidirectional communication. In this review, we discuss the framework of the "FRT-organ axes." Each axis, namely, the vagina-gut axis, uterus-gut axis, ovary-gut axis, vagina-bladder axis, vagina-oral axis, uterus-oral axis, vagina-brain axis, uterus-brain axis, and vagina-joint axis, is comprehensively discussed separately. Each axis could be involved in the pathogenesis of not only gynecological diseases but also diseases occurring apart from the FRT. Although the microbiota is clearly a key player in the FRT-organ axes, more quantitative insight into the homeostasis of the microbiota could be provided by host function measurements rather than current microbe-centric approaches. Therefore, investigation of the FRT-organ axes would provide us with a multicentric approach, including immune, neural, endocrine, and metabolic aspects, for understanding the homeostatic mechanism of women's bodies. The framework of the FRT-organ axes could also provide insights into finding new therapeutic approaches to maintain women's health.

Safety assessment scheme for menstrual cups and application for the evaluation of a menstrual cup comprised of medical grade silicone

BACKGROUND

Ensuring menstrual cup safety is paramount, yet a menstrual cup safety assessment scheme is lacking. This paper presents a quadripartite scheme, showing how it can be applied.

METHODS

The Tampax Menstrual Cup was evaluated in the safety assessment scheme: (1) Biocompatibility and chemical safety of cup constituents. Extractables were obtained under different use condition; exposure-based risk assessments (EBRA) were conducted for extractables exceeding thresholds of toxicological concern. (2) Physical impact to vaginal mucosa. After physical evaluations, the Tampax Cup and another cup were assessed in a randomised double-blinded, two-product, two-period cross-over clinical trial (65 women, mean age 34.2 years). (3) Impact to vaginal microbiota (in vitro mixed microflora assay and evaluation of vaginal swabs). (4) In vitro growth of Staphylococcus aureus and toxic shock syndrome toxin-1 (TSST-1) production.

FINDINGS

Biocompatibility assessments and EBRA of cup constituents showed no safety concerns. In the randomised clinical trial, all potentially product-related adverse effects were mild, vaginal exams were unremarkable, no clinically relevant pH changes occurred, post-void residual urine volume with and without cup were similar, and self-reported measures of comfort along with reports of burning, itching and stinging between cups were comparable. Cup use had no effect on microbial growth in vitro or in the 62 subjects who completed the trial or on in vitro TSST-1 production.

INTERPRETATION

The quadripartite safety assessment scheme allows evaluation of menstrual cup safety. The Tampax Cup is safe and well-tolerated upon intended use. As with all feminine hygiene products, post-market safety surveillance confirmed this conclusion.

FUNDING

By Procter & Gamble.

Draft Genome Sequence of a Lactobacillus gasseri Strain Isolated from the Catheterized Urine of a Healthy Postmenopausal Woman

Urinary microbiome composition has been found to associate with health status and to change with age. Lactobacillus gasseri is one of the most frequently found lactic acid bacteria in the vaginal and urinary tracts of women. Here, we report a draft genome sequence of a urinary L. gasseri strain isolated from a healthy postmenopausal woman.

Genomic insights into Lactobacillus gasseri and Lactobacillus paragasseri

Background

Antimicrobial and antifungal species are essential members of the healthy human microbiota. Several different species of lactobacilli that naturally inhabit the human body have been explored for their probiotic capabilities including strains of the species Lactobacillus gasseri. However, L. gasseri (identified by 16S rRNA gene sequencing) has been associated with urogenital symptoms. Recently a new sister taxon of L. gasseri was described: L. paragasseri. L. paragasseri is also posited to have probiotic qualities.

Methods

Here, we present a genomic investigation of all (n = 79) publicly available genome assemblies for both species. These strains include isolates from the vaginal tract, gastrointestinal tract, urinary tract, oral cavity, wounds, and lungs.

Results

The two species cannot be distinguished from short-read sequencing of the 16S rRNA as the full-length gene sequences differ only by two nucleotides. Based upon average nucleotide identity (ANI), we identified 20 strains deposited as L. gasseri that are in fact representatives of L. paragasseri. Investigation of the genic content of the strains of these two species suggests recent divergence and/or frequent gene exchange between the two species. The genomes frequently harbored intact prophage sequences, including prophages identified in strains of both species. To further explore the antimicrobial potential associated with both species, genome assemblies were examined for biosynthetic gene clusters. Gassericin T and S were identified in 46 of the genome assemblies, with all L. paragasseri strains including one or both bacteriocins. This suggests that the properties once ascribed to L. gasseri may better represent the L. paragasseri species.

Characterization of a novel type of glycogen-degrading amylopullulanase from Lactobacillus crispatus

Glycogen is one of the major carbohydrates utilized by the human vaginal microbiota, which is commonly dominated by Lactobacillus, especially L. crispatus. An in silico analysis predicted that a type I pullulanase was involved in glycogen degradation in L. crispatus. The biochemical and genetic properties of the pullulanase still need to be determined. Here, we de novo identified the glycogen (Glg)-utilization enzyme (named GlgU) from L. crispatus through a biochemical assay. GlgU was optimally active at acidic pH, approximately 4.0 ~ 4.5, and was able to hydrolyze glycogen into low-molecular-weight malto-oligosaccharides. Actually, GlgU was a type II pullulanase (amylopullulanase) with just one catalytic domain that possessed substrate specificity toward both α-1,4 and α-1,6-glucosidic bonds. Phylogenetically, GlgU was obviously divergent from the known amylases and pullulanases (including amylopullulanases) in lactobacilli. In addition, we confirmed the catalytic activity of glgU in a nonglycogen-utilizing lactobacilli strain, demonstrating the essential role of glgU in glycogen metabolism. Overall, this study characterized a novel type of amylopullulanases, contributing to the knowledge of the glycogen utilization mechanism of the dominant species of human vaginal microbiota. KEY POINTS: • GlgU was a type II pullulanase, not a type I pullulanase predicted before. • GlgU was able to completely hydrolyze glycogen into malto-oligosaccharides. • GlgU played a key role in the metabolism of extracellular glycogen.

The right bug in the right place: opportunities for bacterial vaginosis treatment

Bacterial vaginosis (BV) is a condition in which the vaginal microbiome presents an overgrowth of obligate and facultative anaerobes, which disturbs the vaginal microbiome balance. BV is a common and recurring vaginal infection among women of reproductive age and is associated with adverse health outcomes and a decreased quality of life. The current recommended first-line treatment for BV is antibiotics, despite the high recurrence rate. Live biopharmaceutical products/probiotics and vaginal microbiome transplantation (VMT) have also been tested in clinical trials for BV. In this review, we discuss the advantages and challenges of current BV treatments and interventions. Furthermore, we provide our understanding of why current clinical trials with probiotics have had mixed results, which is mainly due to not administering the correct bacteria to the correct body site. Here, we propose a great opportunity for large clinical trials with probiotic strains isolated from the vaginal tract (e.g., Lactobacillus crispatus) and administered directly into the vagina after pretreatment.

Evaluation of Modulatory Activities of Lactobacillus crispatus Strains in the Context of the Vaginal Microbiota

It has been widely reported that members of the genus Lactobacillus dominate the vaginal microbiota, which is represented by the most prevalent species Lactobacillus crispatus, Lactobacillus jensenii, Lactobacillus gasseri, and Lactobacillus iners. L. crispatus is furthermore considered an important microbial biomarker due to its professed beneficial implications on vaginal health. In order to identify molecular mechanisms responsible for health-promoting activities that are believed to be elicited by L. crispatus, we performed in silico investigations of the intraspecies biodiversity of vaginal microbiomes followed by in vitro experiments involving various L. crispatus strains along with other vaginal Lactobacillus species mentioned above. Specifically, we assessed their antibacterial activities against a variety of pathogenic microorganisms that are associated with vaginal infections. Moreover, coculture experiments of L. crispatus strains showing the most antibacterial activity against different pathogens revealed distinct ecological fitness and competitive properties with regard to other microbial colonizers. Interestingly, we observed that even phylogenetically closely related L. crispatus strains possess unique features in terms of their antimicrobial activities and associated competitive abilities, which suggests that they exert marked competition and evolutionary pressure within their specific environmental niche. IMPORTANCE The human vaginal microbiota includes all microorganisms that colonize the vaginal tract. In this context, a vaginal microbiota dominated by Lactobacillus and specifically by Lactobacillus crispatus is considered a hallmark of health. The role of L. crispatus in maintaining host health is linked to its modulatory activity toward other members of the vaginal ecosystem and toward the host. In this study, in vitro experiments followed by genetic analyses of the mechanisms used by L. crispatus in colonizing the vaginal ecological niche, particularly in the production of different antimicrobial compounds, were evaluated, highlighting some intriguing novel aspects concerning the genetic variability of this species. Our results indicate that this species has adapted to its niche and may still undergo adaptation to enhance its competitiveness for niche colonization.

Shotgun metagenomic sequencing revealed the prebiotic potential of a grain-based diet in mice

In the present study, we elucidated the effect of grain-based (GB) diet containing both soluble and insoluble fibers and purified ingredients-based (PIB) diet containing only insoluble fiber, namely cellulose on mice gut microbiome using whole shotgun based metagenomic sequencing. Although the fiber content in both diet types is the same (5%) the presence of soluble fiber only in the GB diet differentiates it from the PIB diet. The taxonomic analysis of sequenced reads reveals a significantly higher enrichment of probiotic Lactobacilli in the GB group as compared to the PIB group. Further, the enhancement of energy expensive cellular processes namely, cell cycle control, cell division, chromosome partitioning, and transcription is observed in the GB group which could be due to the metabolization of the soluble fiber for faster energy production. In contrast, a higher abundance of cellulolytic bacterial community namely, the members of family Lachnospiraceae and Ruminococcaceae and the metabolism functions are found in the PIB group. The PIB group shows a significant increase in host-derived oligosaccharide metabolism functions indicating that they might first target the host-derived oligosaccharides and self-stored glycogen in addition to utilising the available cellulose. In addition to the beneficial microbial community variations, both the groups also exhibited an increased abundance of opportunistic pathobionts which could be due to an overall low amount of fiber in the diet. Furthermore, backtracing analysis identified probiotic members of Lactobacillus, viz., L. crispatus ST1, L. fermentum CECT 5716, L. gasseri ATCC 33323, L. johnsonii NCC 533 and L. reuteri 100-23 in the GB group, while Bilophila wadsworthia 3_1_6, Desulfovibrio piger ATCC 29098, Clostridium symbiosum WAL-14163, and Ruminococcaceae bacterium D16 in the PIB group. These data suggest that Lactobacilli, a probiotic community of microorganisms, are the predominant functional contributors in the gut of GB diet-fed mice, whereas pathobionts too coexisted with commensals in the gut microbiome of the PIB group. Thus at 5% fiber, GB modifies the gut microbial ecology more effectively than PIB and the inclusion of soluble fiber in the GB diet may be one of the primary factors responsible for this impact.

Maturation of the oral microbiota during primary teeth eruption: a longitudinal, preliminary study

Introduction

Oral microbiota that established in the early years of life may influence the child’s oral health in the long term. Until now, no consensus is reached about whether the development of the oral microbiota is more related with age increase or more with teeth eruption.

Objective

To analyze the microbiota development of both saliva and supragingival plaque during the gradual eruption of primary teeth in caries-free infants and toddlers.

Methods

Saliva and plaque samples were collected at five and four dentition states, respectively, and were identified by bacterial 16S rRNA gene sequencing.

Results

During the longitudinal observation, the saliva ecosystem seemed more complex and dynamic than the plaque, with larger bacteria quantity and more significantly varied species over time. About 70% of the initial colonized OTUs in plaque persisted until the completion of the primary dentition. Transient bacteria were mostly detected in the early saliva and plaque microbiota, which came from the environment and other sites of the human body. Microbial diversity in both saliva and plaque varied greatly from pre-dentition to full eruption of eight anterior teeth, but not during the eruption of primary molars.

Conclusion

Oral bacterial development follows an ordered sequence during the primary teeth eruption. ‘Fully eruption of all primary anterior teeth’ is a critical stage in this process.

Lactiplantibacillus plantarum LRCC5314 includes a gene for serotonin biosynthesis via the tryptophan metabolic pathway

As the functions of probiotics within the same species may not be shared, it is important to analyze the genetic characteristics of strains to determine their safety and usefulness before industrial applications. Hence the present study was undertaken to determine functional genes, and beneficial activities of strain LRCC5314, a bacterial strain isolated from kimchi through comparative genomic analysis. Phylogenetic analysis based on the 16S rRNA gene sequence showed that strain LRCC5314 was a member of the species L. plantarum. Whole genome size of strain LRCC5314 was sequence was 3.25 Mb long, with a G + C content of 44.5 mol% and 3,031 predicted genes. Strain LRCC5314 could metabolize hexoses through homofermentation, which produces only lactic acid from hexoses. According to gene annotation, strain LRCC-5314 contained genes of EPS production and CRISPR. Moreover, the strain contained genes that could encode a complete biosynthetic pathway for the production of tryptophan, which can be used as a precursor of serotonin. Notably, the tryptophan and serotonin activities strain LRCC5314 were higher than those of reference strains, L. plantarum ATCC 14917^T, DSM 20246, DSM 2601, and ATCC 8014, which reach tryptophan amount of 0.784 ± 0.045 μM/ml in MRS broth and serotonin concentration of 19.075 ± 0.295 ng/ml in HT-22 cells. These findings indicated that L. plantarum LRCC5314 could provide a source for serotonin production and could be used as a functional probiotic for stress regulation.

Probiotic lactobacilli in formulas and hygiene products for the health of the urogenital tract

Lactobacilli are the predominant microorganisms of the healthy human vagina. A novel alternative for the prevention and treatment of female urogenital tract infections (UGTI) is the inclusion of these microorganisms as active pharmaceutical ingredients in probiotic formulas, and more recently in female hygienic products. Probiotics are defined as “live microorganisms that, when administered in adequate amounts, confer a health benefit on the host.” A list of requirements must be considered during the development of probiotic product/formula for the female urogenital tract (UGT). This review aims to resume the requirements, probiotic characteristics, and clinical trial applied to determine the effect of probiotic and potentially probiotic strains on different woman’s physiological and pathological conditions, and in preterm birth prevention. A revision of female hygienic products available in the world market is included, together with novel studies applying nanotechnology for Lactobacillus incorporation in hygienic products. Further studies and well‐designed clinical trials are urgently required to complement the current knowledge and applications of probiotics in the female UGT. The use of probiotic formulas and products will improve and restore the ecological equilibrium of the UGT microbiome to prevent and treat UGTI in women under different conditions.

Comparative Effectiveness of Treatments for Bacterial Vaginosis: A Network Meta-Analysis

Bacterial vaginosis (BV) is a common vaginal dysbiosis in women of reproductive age. However, the cure rate for BV varies considerably and many women experience a relapse after the initial treatment. The present meta-analysis aimed to evaluate the clinical cure rates (CCRs) in randomized controlled trials (RCTs) through different therapies and administration routes. This meta-analysis included a final set of 25 eligible studies with a total of 57 RCTs and compared the effectiveness of BV treatments among non-pregnant and pregnant women. The initial range of CCRs varied greatly from 46.75% to 96.20% and the final pooled CCR was 75.5% (CI: 69.4-80.8) using the random model. The heterogeneity indices were Q = 418.91, I2 = 94.27%, and τ = 0.7498 (p < 0.0001). No publication bias was observed according to Funnel plot symmetry and Egger's linear regression test (p = 0.1097). To evaluate different variables, sub-group analysis, meta-regressions, and network meta-analysis were also realized. The highest P-scores in CCR were obtained by: (1) a combined therapy with local probiotic treatment and application of antibiotics by both administration route (oral clindamycin and local 5-nitroimidazole; P-score = 0.92); (2) a combined therapy with oral administration of 5-nitroimidazole and probiotic treatment (P-score = 0.82); (3) and a combined therapy with local administration of 5-nitroimidazole and oral probiotic treatment (P-score = 0.68). A clear-cut decision of the best BV treatment was not possible due to the heterogeneity of outcomes reported in the trials, indicating the necessity for a better characterization of RCTs. Finally, combined therapies suggested the reduction of the optimal concentration of antibiotics, and double phase treatments of antibiotics indicated an increment of CCRs in BV.

Insight into phenotypic and genotypic differences between vaginal Lactobacillus crispatus BC5 and Lactobacillus gasseri BC12 to unravel nutritional and stress factors influencing their metabolic activity

The vaginal microbiota, normally characterized by lactobacilli presence, is crucial for vaginal health. Members belonging to L. crispatus and L. gasseri species exert crucial protective functions against pathogens, although a total comprehension of factors that influence their dominance in healthy women is still lacking. Here we investigated the complete genome sequence and comprehensive phenotypic profile of L. crispatus strain BC5 and L. gasseri strain BC12, two vaginal strains featured by anti-bacterial and anti-viral activities. Phenotype microarray (PM) results revealed an improved capacity of BC5 to utilize different carbon sources as compared to BC12, although some specific carbon sources that can be associated to the human diet were only metabolized by BC12, i.e. uridine, amygdalin, tagatose. Additionally, the two strains were mostly distinct in the capacity to utilize the nitrogen sources under analysis. On the other hand, BC12 showed tolerance/resistance towards twice the number of stressors (i.e. antibiotics, toxic metals etc.) with respect to BC5. The divergent phenotypes observed in PM were supported by the identification in either BC5 or BC12 of specific genetic determinants that were found to be part of the core genome of each species. The PM results in combination with comparative genome data provide insights into the possible environmental factors and genetic traits supporting the predominance of either L. crispatus BC5 or L. gasseri BC12 in the vaginal niche, giving also indications for metabolic predictions at the species level.

Comparative genome analyses of Lactobacillus crispatus isolated from different ecological niches reveal an environmental adaptation of this species to the human vaginal environment

Vaginal microbiota is defined as the community of bacteria residing in the human vaginal tract. Recent studies have demonstrated that the vaginal microbiota is dominated by members of the Lactobacillus genus, whose relative abundance and microbial taxa composition are dependent on the healthy status of this human body site. Particularly, among members of this genus, the high prevalence of Lactobacillus crispatus is commonly associated with a healthy vaginal environment. In the current study, we assessed the microbial composition of 94 healthy vaginal microbiome samples through shotgun metagenomics analyses. Based on our results we observed that L. crispatus was the most representative species and correlated negatively with bacteria involved in vaginal infections. Therefore, we isolated fifteen L. crispatus strains from different environments in which this species is abounding, ranging from vaginal swabs of healthy women to chicken fecal samples. The genomes of these strains were decoded and their genetic content was analyzed and correlated with their physiological features. An extensive comparative genomic analysis encompassing all publicly available genome sequences of L. crispatus and combined with those decoded in this study, revealed a genetic adaptation of strains to their ecological niche. In addition, in vitro growth experiments involving all isolated L. crispatus strains together with a synthetic vaginal microbiota reveal how this species is able to modulate the composition of the vaginal microbial consortia at strain level. Overall, our findings suggest that L. crispatus plays an important ecological role in reducing the complexity of the vaginal microbiota by depleting pathogenic bacteria.Importance The vaginal microbiota is defined as the community of bacteria residing in the human vaginal tract. Recent studies have demonstrated that the high prevalence of Lactobacillus crispatus species is commonly associated with a healthy vaginal environment. In the current study, we assessed the microbial composition of 94 public healthy vaginal samples through shotgun metagenomics analyses. Results showed that L. crispatus was the most representative species and correlated negatively with bacteria involved in vaginal infections. Moreover, we isolated and sequenced the genome of new L. crispatus strains from different environments and the comparative genomics analysis revealed a genetic adaptation of strains to their ecological niche. In addition, in-vitro growth experiments display the capability of this species to modulate the composition of the vaginal microbial consortia. Overall, our findings suggest an ecological role exploited by L. crispatus in reducing the complexity of the vaginal microbiota toward a depletion of pathogenic bacteria.

Probiogenomics Analysis of 97 Lactobacillus crispatus Strains as a Tool for the Identification of Promising Next-Generation Probiotics

Members of the genus Lactobacillus represent the most common colonizers of the human vagina and are well-known for preserving vaginal health and contrasting the colonization of opportunistic pathogens. Remarkably, high abundance of Lactobacillus crispatus in the vaginal environment has been linked to vaginal health, leading to the widespread use of many L. crispatus strains as probiotics. Nevertheless, despite the scientific and industrial relevance of this species, a comprehensive investigation of the genomics of L. crispatus taxon is still missing. For this reason, we have performed a comparative genomics analysis of 97 L. crispatus strains, encompassing 16 strains sequenced in the framework of this study alongside 81 additional publicly available genome sequences. Thus, allowing the dissection of the L.crispatus pan-genome and core-genome followed by a comprehensive phylogenetic analysis based on the predicted core genes that revealed clustering based on ecological origin. Subsequently, a genomics-targeted approach, i.e., probiogenomics analysis, was applied for in-depth analysis of the eight L. crispatus strains of human origin sequenced in this study. In detail their genetic repertoire was screened for strain-specific genes responsible for phenotypic features that may guide the identification of optimal candidates for next-generation probiotics. The latter includes bacteriocin production, carbohydrates transport and metabolism, as well as a range of features that may be responsible for improved ecological fitness. In silico results regarding the genetic repertoire involved in carbohydrate metabolism were also validated by growth assays on a range of sugars, leading to the selection of putative novel probiotic strains.

Adaptive response to iterative passages of five Lactobacillus species in simulated vaginal fluid

Background

Microbiome and metagenomic studies have given rise to a new understanding of microbial colonization of various human tissues and their ability to impact our health. One human microbiome growing in notoriety, the vaginal microbiome, stands out given its importance for women’s health, and is peculiar in terms of its relative bacterial composition, including its simplicity and typical domination by a small number of Lactobacillus species. The loss of Lactobacillus dominance is associated with disorders such as bacterial vaginosis, and efforts are now underway to understand the ability of Lactobacillus species to colonize the vaginal tract and adapt to this dynamic and acidic environment. Here, we investigate how various Lactobacillus species often isolated from the vaginal and intestinal cavities genomically and transcriptionally respond to iterative growth in simulated vaginal fluid.

Results

We determined the genomes and transcriptomes of L. acidophilus, L. crispatus, L. fermentum, L. gasseri, and L. jensenii and compared profiles after 50, 100, 500, and 1000 generations of iterative passages in synthetic vaginal fluid. In general, we identified relatively few genetic changes consisting of single nucleotide polymorphisms, with higher counts occurring more frequently in non-vaginal isolated species. Transcriptional profiles were more impacted over time and tended to be more extensive for species that typically do not dominate the vaginal tract, reflecting a more extensive need to adapt to a less familiar environment.

Conclusions

This study provides insights into how vaginal and non-vaginal Lactobacillus species respond and adapt to a simulated vaginal environment. Overall, trends indicate high genomic stability for all species involved, with more variability in the transcriptome especially for non-dominant species of the vaginal tract.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-020-02027-8.

Screening of autochthonous vaginal beneficial lactobacilli strains by their growth at high temperatures for technological applications

The pharmaceutical industry shows an emerging interest in formulas that contain live and beneficial microorganisms, also known as probiotics or pharmabiotics, which in many cases, are host-specific. The resistance to higher temperature is an essential feature of these microorganisms when working on the design of products for vaginal formula. In order to obtain a high number of viable cells and a prolonged shelf life in the designed product, it is required to apply technological procedures using high temperatures or abrupt changes of them, which result in conditions that are different from the optimal growth temperature and can affect the metabolic capabilities of the bacteria when administered to the host in order to reestablish the ecological mucosa. The aim of this work was to evaluate the behavior of 30 different species and strains of autochthonous beneficial vaginal lactobacilli (BVL) when exposed to high temperatures, determine their survival capabilities and analyze their pre-adaptation to those temperatures, in order that they still maintain their viability after technological processes and further conservation. BVL were exhibited to temperatures higher than optimal, with the purpose of evaluating their growth kinetics and parameters. Later, they were exposed to higher temperatures, and then, returned to their optimal, to determine if they were able to grow again. The strains that showed higher resistance were selected, and their viability and beneficial properties studied further. The growth kinetics of strains exposed to higher temperatures showed different patterns, which provided evidence that the thermal adaptation is strain-dependent and is not related to any particular species and/or metabolic group in which the strains were taxonomically classified. The pre-adaptive step allowed the growth of some of the strains, preserving their viability and probiotic properties after the high temperatures were applied. The results shows that BVL can be exposed to high temperatures used in different technological processes that are applied for pharmabiotic formulations, such as spray dried or vacuum rotary evaporation, and/or during the conservation period. The results obtained indicate that some specific BVL strains resist high temperatures and grow afterwards at optimal conditions.

Can Probiotics and Diet Promote Beneficial Immune Modulation and Purine Control in Coronavirus Infection?

Infection caused by the SARS-CoV-2 coronavirus worldwide has led the World Health Organization to declare a COVID-19 pandemic. Because there is no cure or treatment for this virus, it is emergingly urgent to find effective and validated methods to prevent and treat COVID-19 infection. In this context, alternatives related to nutritional therapy might help to control the infection. This narrative review proposes the importance and role of probiotics and diet as adjunct alternatives among the therapies available for the treatment of this new coronavirus. This review discusses the relationship between intestinal purine metabolism and the use of Lactobacillus gasseri and low-purine diets, particularly in individuals with hyperuricemia, as adjuvant nutritional therapies to improve the immune system and weaken viral replication, assisting in the treatment of COVID-19. These might be promising alternatives, in addition to many others that involve adequate intake of vitamins, minerals and bioactive compounds from food.

Comparative Genomics of Lactobacillus crispatus from the Gut and Vagina Reveals Genetic Diversity and Lifestyle Adaptation

Lactobacillus crispatus colonizes the human feces, human vagina, and the crops and ceca of chicken. To explore the genetic characteristics and evolutionary relationships of L. crispatus isolated from different niches, we selected 37 strains isolated from the human vagina (n = 17), human feces (n = 11), and chicken feces (n = 9), and used comparative genomics to explore the genetic information of L. crispatus from the feces and vagina. No significant difference was found in the three sources of genomic features such as genome size, GC content, and number of protein coding sequences (CDS). However, in a phylogenetic tree constructed based on core genes, vagina-derived L. crispatus and feces-derived strains were each clustered separately. Therefore, the niche exerted an important impact on the evolution of L. crispatus. According to gene annotation, the L. crispatus derived from the vagina possessed a high abundance of genes related to acid tolerance, redox reactions, pullulanase, and carbohydrate-binding modules (CBMs). These genes helped L. crispatus to better adapt to the acidic environment of the vagina and obtain more nutrients, maintaining its dominance in the vagina in competition with other strains. In feces-derived bacteria, more genes encoding CRISPR/Cas system, glycoside hydrolases (GHs) family, and tetracycline/lincomycin resistance genes were found to adapt to the complex intestinal environment. This study highlights the evolutionary relationship of L. crispatus strains isolated from the vagina and feces, and the adaptation of L. crispatus to the host environment.