1.
Contribution of Lactobacillus iners to Vaginal Health and Diseases: A Systematic Review.
Zheng, N, Guo, R, Wang, J, Zhou, W, Ling, Z
Frontiers in cellular and infection microbiology. 2021;11:792787
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The vaginal microbiome is an important contributor to vaginal health. Here the dominance of Lactobacilli species, alongside their antimicrobial compounds play a critical role in contributing and protecting the vaginal milieu. Conversely the disruption or absence of Lactobacilli dominance is frequently associated with vaginal disease and infections. One of the Lactobacilli species prevalent in the vaginal microbiome is Lactobacillus iners. It was long overlooked in research due to it being so difficult to culture, and it was first identified in 1999 thanks to DNA sequencing. Researchers since discovered that the relationship between L. iners and vaginal health is far more complicated and ambiguous compared to the other Lactobacilli species. This systematic review explores the current knowledge of the characteristics of L. iners and its role in vaginal health and disease. The article discusses L. iners identification, genetic make up and differences to other Lactobacilli species and how they relate to vaginal health. The article also summarizes L. iners nutrient requirements and its role in diseases like dysbiosis, bacterial vaginosis, sexually transmitted infections and biofilm formation. Furthermore the authors look at the relation between L. iners and premature birthing, fertility and menstrual cycles. A final section in discusses the antimicrobial and immune sytem activating qualities of L. iners. In light of all these findings the authors describe L . iners as a very unique Lactobacilli due to its unusual characteristics. Whether L. iners is beneficial or pathogenic for the host remains controversial, as it can adapt to high and low pH environment and is seen in health and equally dysbiotic states of infection. Hence some describe it as a transitional species that colonizes the vagina after disturbances. It may be a risk factor for infections by contributing to the onset and maintenance of dysbiotic disturbances. Further studies are needed to clarify the role of L. iners and its role on vaginal health and whether it could serve as a biomarker for vaginal inflammation. This article is a useful summary about the characteristics and role of L. iners in vaginal health in disease.
Abstract
Lactobacillus iners, first described in 1999, is a prevalent bacterial species of the vaginal microbiome. As L. iners does not easily grow on de Man-Rogosa-Sharpe agar, but can grow anaerobically on blood agar, it has been initially overlooked by traditional culture methods. It was not until the wide application of molecular biology techniques that the function of L. iners in the vaginal microbiome was carefully explored. L. iners has the smallest genome among known Lactobacilli and it has many probiotic characteristics, but is partly different from other major vaginal Lactobacillus species, such as L. crispatus, in contributing to the maintenance of a healthy vaginal microbiome. It is not only commonly present in the healthy vagina but quite often recovered in high numbers in bacterial vaginosis (BV). Increasing evidence suggests that L. iners is a transitional species that colonizes after the vaginal environment is disturbed and offers overall less protection against vaginal dysbiosis and, subsequently, leads to BV, sexually transmitted infections, and adverse pregnancy outcomes. Accordingly, under certain conditions, L. iners is a genuine vaginal symbiont, but it also seems to be an opportunistic pathogen. Further studies are necessary to identify the exact role of this intriguing species in vaginal health and diseases.
2.
Disruption of the Gut Ecosystem by Antibiotics.
Yoon, MY, Yoon, SS
Yonsei medical journal. 2018;59(1):4-12
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The gut microbiome is a complex ecosystem of different micro-organisms, such as bacteria, viruses and fungi, living in the human intestines. It’s involved in numerous functions, such as extracting energy and nutrition from food, protecting against disease-causing microorganisms, and supporting the immune system of the host, and therefore affecting human health and disease. This paper is a review of studies on the effects of antibiotics on the gut microbiota. It outlines how different types of antibiotics can alter the intestinal environment and the composition of the microbes, resulting in various physiological changes that can trigger disease. Relevant mechanisms, such as inflammatory response and the use of intestinal nutrients by infectious bacteria are discussed. Finally, it discusses faecal microbiota transplantation (FMT) and probiotics as treatment approaches, aimed at restoring a disturbed intestinal environment.
Abstract
The intestinal microbiota is a complex ecosystem consisting of various microorganisms that expands human genetic repertoire and therefore affects human health and disease. The metabolic processes and signal transduction pathways of the host and intestinal microorganisms are intimately linked, and abnormal progression of each process leads to changes in the intestinal environment. Alterations in microbial communities lead to changes in functional structures based on the metabolites produced in the gut, and these environmental changes result in various bacterial infections and chronic enteric inflammatory diseases. Here, we illustrate how antibiotics are associated with an increased risk of antibiotic-associated diseases by driving intestinal environment changes that favor the proliferation and virulence of pathogens. Understanding the pathogenesis caused by antibiotics would be a crucial key to the treatment of antibiotic-associated diseases by mitigating changes in the intestinal environment and restoring it to its original state.
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Fecal Microbiome and Food Allergy in Pediatric Atopic Dermatitis: A Cross-Sectional Pilot Study.
Fieten, KB, Totté, JEE, Levin, E, Reyman, M, Meijer, Y, Knulst, A, Schuren, F, Pasmans, SGMA
International archives of allergy and immunology. 2018;175(1-2):77-84
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Atopic diseases, such as atopic dermatitis (AD), asthma and rhinitis, are on the increase worldwide. Exposure to microbes may be important in the development of an atopic disease. Specifically, reduced early-life exposure is thought to be a contributing factor because microbial colonisation of the intestines during infancy plays a crucial role in the maturation of the immune system. AD, also called eczema, is an inflammatory skin disease often seen in small children. Food allergies are common in children with AD, the most common allergens being eggs, cow’s milk, peanuts, soy and wheat. This cross-sectional observational pilot study with 82 young children with a diagnosis of AD set out to identify distinct microbial patterns in the children’s faecal microbiomes associated with a clinical diagnosis of food allergy. Stool and blood samples were collected for a microbiome analysis and IgE antibody measurement, respectively. 20 children had a confirmed food allergy (most commonly to cow’s milk and peanuts), while almost half of the children without a diagnosed food allergy were sensitised to common food allergens after a food challenge. The study identified a faecal microbial signature in children with AD that differentiates between the presence and absence of food allergy. Children with AD and food allergy had more Escherichia coli and Bifidobacterium pseudocatenulatum species and less Bifidobacterium breve, Faecalibacterium prausnitzii and Akkermansia muciniphila species than children without food allergy. The authors concluded that the study supports a hypothesis that the intestinal microbiome differs in children with AD, depending on whether they have a food allergy or not. They call for future studies to confirm these findings.
Abstract
BACKGROUND Exposure to microbes may be important in the development of atopic disease. Atopic diseases have been associated with specific characteristics of the intestinal microbiome. The link between intestinal microbiota and food allergy has rarely been studied, and the gold standard for diagnosing food allergy (double-blind placebo-controlled food challenge [DBPCFC]) has seldom been used. We aimed to distinguish fecal microbial signatures for food allergy in children with atopic dermatitis (AD). METHODS Pediatric patients with AD, with and without food allergy, were included in this cross-sectional observational pilot study. AD was diagnosed according to the UK Working Party criteria. Food allergy was defined as a positive DBPCFC or a convincing clinical history, in combination with sensitization to the relevant food allergen. Fecal samples were analyzed using 16S rRNA microbial analysis. Microbial signature species, discriminating between the presence and absence food allergy, were selected by elastic net regression. RESULTS Eighty-two children with AD (39 girls) with a median age of 2.5 years, and 20 of whom were diagnosed with food allergy, provided fecal samples. Food allergy to peanut and cow's milk was the most common. Six bacterial species from the fecal microbiome were identified, that, when combined, distinguished between children with and without food allergy: Bifidobacterium breve, Bifidobacterium pseudocatenulatum, Bifidobacterium adolescentis, Escherichia coli, Faecalibacterium prausnitzii, and Akkermansia muciniphila (AUC 0.83, sensitivity 0.77, specificity 0.80). CONCLUSIONS In this pilot study, we identified a microbial signature in children with AD that discriminates between the absence and presence of food allergy. Future studies are needed to confirm our findings.