Prevalence of fungi in the vagina, rectum and oral cavity in pregnant diabetic women: relation to gestational age and symptoms

Ascomycetes yeasts: The hidden part of human microbiome

The fungal component of the microbiota, the mycobiota, has been neglected for a long time due to its poor richness compared to bacteria. Limitations in fungal detection and taxonomic identification arise from using metagenomic approaches, often borrowed from bacteriome analyses. However, the relatively recent discoveries of the ability of fungi to modulate the host immune response and their involvement in human diseases have made mycobiota a fundamental component of the microbial communities inhabiting the human host, deserving some consideration in host-microbe interaction studies and in metagenomics. Here, we reviewed recent data on the identification of yeasts of the Ascomycota phylum across human body districts, focusing on the most representative genera, that is, Saccharomyces and Candida. Then, we explored the key factors involved in shaping the human mycobiota across the lifespan, ranging from host genetics to environment, diet, and lifestyle habits. Finally, we discussed the strengths and weaknesses of culture-dependent and independent methods for mycobiota characterization. Overall, there is still room for some improvements, especially regarding fungal-specific methodological approaches and bioinformatics challenges, which are still critical steps in mycobiota analysis, and to advance our knowledge on the role of the gut mycobiota in human health and disease. This article is categorized under: Immune System Diseases > Genetics/Genomics/Epigenetics Immune System Diseases > Environmental Factors Infectious Diseases > Environmental Factors.

The Maternal Microbiome and Gestational Diabetes Mellitus: Cause and Effect

Gestational diabetes mellitus (GDM) is a growing public health concern that affects many pregnancies globally. The condition is associated with adverse maternal and neonatal outcomes including gestational hypertension, preeclampsia, placental abruption, preterm birth, stillbirth, and fetal growth restriction. In the long-term, mothers and children have an increased risk of developing metabolic diseases such as type 2 diabetes and cardiovascular disease. Accumulating evidence suggest that alterations in the maternal microbiome may play a role in the pathogenesis of GDM and adverse pregnancy outcomes. This review describes changes in the maternal microbiome during the physiological adaptations of pregnancy, GDM and adverse maternal and neonatal outcomes. Findings from this review highlight the importance of understanding the link between the maternal microbiome and GDM. Furthermore, new therapeutic approaches to prevent or better manage GDM are discussed. Further research and clinical trials are necessary to fully realize the therapeutic potential of the maternal microbiome and translate these findings into clinical practice.

The Association between Gestational Diabetes Mellitus and Infections in Pregnancy-Systematic Review and Meta-Analysis

We conducted a systematic review and meta-analysis to evaluate the association between gestational diabetes mellitus and infections during pregnancy. We included cross-sectional, case-control, cohort studies and clinical trials, evaluating the frequency of infections in women with and without gestational diabetes mellitus. A search was conducted in Embase, PubMed, and Web of Science electronic databases and by manually searching references, until 23 March 2022, resulting in 16 studies being selected for review, with 111,649 women in the gestational diabetes mellitus group, and 1,429,659 in the controls. Cochrane's Q test of heterogeneity and I² were used to assess heterogeneity. Pooled odds ratio (OR) was calculated. Funnel plots and Egger test were used for assessment of publication bias. The results showed a significant association between gestational diabetes mellitus and infections (pooled-OR 1.3 95% CI [1.2-1.5]). Sub-analyses showed a significant association for urinary tract infections (pooled-OR of 1.2 95% CI [1.1-1.3]), bacterial infections (pooled-OR were 1.2 95% CI [1.1-1.4]), and SARS-CoV-2 (pooled-OR 1.5 95% CI [1.2-2.0]) but not to gingivitis or vaginal candidiasis. The results underscore the significance of acknowledging gestational diabetes mellitus as a risk factor for infections.

Growing importance of urogenital candidiasis in individuals with diabetes: A narrative review

Both diabetes and fungal infections contribute significantly to the global disease burden, with increasing trends seen in most developed and developing countries during recent decades. This is reflected in urogenital infections caused by Candida species that are becoming ever more pervasive in diabetic patients, particularly those that present with unsatisfactory glycemic control. In addition, a relatively new group of anti-hyperglycemic drugs, known as sodium glucose cotransporter 2 inhibitors, has been linked with an increased risk for colonization of the urogenital region with Candida spp., which can subsequently lead to an infectious process. In this review paper, we have highlighted notable virulence factors of Candida species (with an emphasis on Candida albicans) and shown how the interplay of many pathophysiological factors can give rise to vulvovaginal candidiasis, potentially complicated with recurrences and dire pregnancy outcomes. We have also addressed an increased risk of candiduria and urinary tract infections caused by species of Candida in females and males with diabetes, further highlighting possible complications such as emphysematous cystitis as well as the risk for the development of balanitis and balanoposthitis in (primarily uncircumcised) males. With a steadily increasing global burden of diabetes, urogenital mycotic infections will undoubtedly become more prevalent in the future; hence, there is a need for an evidence-based approach from both clinical and public health perspectives.

Association of vaginal dysbiosis and gestational diabetes mellitus with adverse perinatal outcomes

OBJECTIVE

Gestational diabetes mellitus (GDM) is associated with adverse perinatal outcomes and is an independent risk factor for vaginal dysbiosis. Understanding the vaginal microbiota in health and disease is essential to screen, detect, and manage complications of pregnancy. Therefore, the aims of the present study were to assess and compare vaginal dysbiosis in pregnancy in women with and without GDM and examine its impact on perinatal outcomes in our population.

METHODS

The present study was a prospective cohort study recruiting pregnant women. The subjects were divided into two groups (GDM and non-GDM) and were followed until delivery to assess fetomaternal outcomes. Vaginal samples were collected at 24-28 weeks and 34-38 weeks for Nugent scoring and determination of bacterial and fungal species.

RESULTS

The study recruited 502 pregnant women, with a final assessment of 320 mother-infant pairs (GDM n = 134; non-GDM n = 186). We found a significant association of vaginal dysbiosis with GDM and adverse perinatal outcomes. Significant differences were also seen in status of infection and its trimester-wise changes in relation to hyperglycemia.

CONCLUSION

By defining an association of vaginal dysbiosis with GDM and its correlation with perinatal outcomes, the present study calls for exploitation of this potential association as a new target in the prevention and treatment of GDM and in alleviating their undesired maternal and infant outcomes.

Candida Chorioamnionitis in Mothers with Gestational Diabetes Mellitus: A Report of Two Cases

Background:Candida chorioamnionitis is rarely encountered, even though vulvovaginal candidiasis incidence is about 15%. Interestingly, it has characteristic gross and histological findings on the umbilical cord that are not to be missed. Case Report: We report two cases of Candida chorioamnionitis with presence of multiple yellowish and red spots of the surface of the umbilical cord. Microscopically, these consist of microabscesses with evidence of fungal yeasts and pseudohyphae. The yeasts and pseudohyphae were highlighted by periodic acid– Schiff and Grocott methenamine silver histochemical stains. Both cases were associated with a history of gestational diabetes mellitus. Discussion: Peripheral funisitis is a characteristic feature of Candida chorioamnionitis. It is associated with high risk of adverse perinatal and neonatal outcomes, such as preterm delivery, stillbirth and neonatal death. We recommend careful examination of the umbilical cord of mothers with gestational diabetes mellitus.

The Role of Fatty Acid Metabolites in Vaginal Health and Disease: Application to Candidiasis

Although the vast majority of women encounters at least one vaginal infection during their life, the amount of microbiome-related research performed in this area lags behind compared to alternative niches such as the intestinal tract. As a result, effective means of diagnosis and treatment, especially of recurrent infections, are limited. The role of the metabolome in vaginal health is largely elusive. It has been shown that lactate produced by the numerous lactobacilli present promotes health by limiting the chance of infection. Short chain fatty acids (SCFA) have been mainly linked to dysbiosis, although the causality of this relationship is still under debate. In this review, we aim to bring together information on the role of the vaginal metabolome and microbiome in infections caused by Candida. Vulvovaginal candidiasis affects near to 70% of all women at least once in their life with a significant proportion of women suffering from the recurrent variant. We assess the role of fatty acid metabolites, mainly SCFA and lactate, in onset of infection and virulence of the fungal pathogen. In addition, we pinpoint where lack of research limits our understanding of the molecular processes involved and restricts the possibility of developing novel treatment strategies.

Emergence of Vulvovaginal Candidiasis among Lebanese Pregnant Women: Prevalence, Risk Factors, and Species Distribution

Objective

Candida species colonize the vagina in at least 20% of women, with rates rising to 30% during pregnancy. This study aimed at determining the prevalence and risk factors of vulvovaginal candidiasis (VVC) in pregnant women at 35-37 weeks of gestation. It also aims at finding possible correlations between VVC and vaginal colonization by other agents, such as Group B Streptococcus (GBS) and bacterial vaginosis.

Methodology

Over a one-year period, high vaginal swabs were collected from pregnant women during their regular antenatal checkup in different polyclinics in Beirut and South Lebanon. Swabs were examined microscopically, cultured on Sabouraud Dextrose Agar, and Candida isolates were identified using Chromatic Candida medium and Germ Tube Test.

Results

VVC was detected in 44.8% of samples, with C. glabrata (44.4%) and C. albicans (43.4%) being the most isolated species. Approximately, half of pregnant women (57.7%) were coinfected with Candida and bacterial vaginosis, while 26% of them carried simultaneously Candida spp. and GBS. No significant correlation was found between the occurrence of VVC and demographic, clinical, medical, and reproductive health characteristics of pregnant women. In contrast, participants with previous miscarriages and those being hospitalized during the past 12 months were more susceptible to develop vaginal C. krusei infection in comparison to other Candida species (p=0.0316 and p=0.0042, respectively).

Conclusion

The prevalence of VVC in pregnant women is an increasing trend in our community. Therefore, routine medical examination and regular screening for candidiasis in the antenatal care program is highly recommended to manage the disease and its complications.

Candida sp. Infections in Patients with Diabetes Mellitus

Candidiasis has increased substantially worldwide over recent decades and is a significant cause of morbidity and mortality, especially among critically ill patients. Diabetes mellitus (DM) is a metabolic disorder that predisposes individuals to fungal infections, including those related to Candida sp., due to a immunosuppressive effect on the patient. This review aims to discuss the latest studies regarding the occurrence of candidiasis on DM patients and the pathophysiology and etiology associated with these co-morbidities. A comprehensive review of the literature was undertaken. PubMed, Scopus, Elsevier’s ScienceDirect, and Springer’s SpringerLink databases were searched using well-defined search terms. Predefined inclusion and exclusion criteria were applied to classify relevant manuscripts. Results of the review show that DM patients have an increased susceptibility to Candida sp. infections which aggravates in the cases of uncontrolled hyperglycemia. The conclusion is that, for these patients, the hospitalization periods have increased and are commonly associated with the prolonged use of indwelling medical devices, which also increase the costs associated with disease management.

Invasive Fungal Infections in Neonates in Canada: Epidemiology and Outcomes

BACKGROUND

Neonatal fungemia is associated with adverse neonatal outcomes and higher overall healthcare expenditure. Our objective is to review the epidemiology of invasive fungal infections (IFIs) in neonates in Canada.

METHODS

A retrospective cohort study using data collected by the Canadian Neonatal Network (CNN) was conducted. Using a nested matched cohort study design, risk factors and outcomes of neonates born <33 weeks gestation (n = 39,305) during 2003-2013 were compared between neonates diagnosed with an IFI during their stay to infection-free controls.

RESULTS

Overall incidence of IFI among all admitted neonates was 0.22% (n = 286), while the incidence of IFI in the group of neonates born <33 weeks gestation was 0.64%. Of the isolates, 170 (59%) had Candida albicans and 59 (21%) had Candida parapsilosis. Risk factors for IFI were lower gestation, male sex, Apgar score <7 at 5 minutes, higher severity of illness score, maternal diabetes and vaginal birth. Neonates with IFI had higher odds of mortality [adjusted odds ratio (aOR): 1.60; 95% confidence interval (CI): 1.06-2.43], necrotizing enterocolitis (aOR: 2.97; 95% CI: 1.76-5.01) and severe retinopathy of prematurity (aOR: 2.15; 95% CI: 1.26-3.67).

CONCLUSIONS

The overall incidence of IFI in neonates was low in Canada in comparison to other large population cohort studies; however, the mortality and morbidity remained high.

Association of gestational diabetes mellitus and abnormal vaginal flora with adverse pregnancy outcomes

Gestational diabetes mellitus (GDM) is associated with adverse perinatal outcomes. This study aimed to examine the association between GDM and abnormal vaginal flora, and the association between abnormal vaginal flora and adverse pregnancy outcomes.This was a prospective study of pregnant women who visited Xuanwu Hospital of the Capital Medical University (Beijing, China) between February and October 2015. All women were screened for GDM according to the International Association of the Diabetes and Pregnancy Study Groups (IADPSG) recommendations. Vaginal secretions were sampled at 28 to 30 and 37 to 40 weeks. Microorganisms were examined.The women were 28.3 ± 2.6 years and their body mass index was 22.8 ± 1.4 kg/m. GDM was associated with higher frequencies of vulvovaginal candidiasis (22.6% vs 9.7%, P < .001), premature rupture of membranes (PROM) (22.6% vs 11.5%, P = .004), premature delivery (16.1% vs 5.5%, P = .02), chorioamnionitis/puerperal infection (19.4% vs 4.5%, P < .001), macrosomia (9.7% vs 4.0%, P = .04), neonatal hypoglycemia (5.4% vs 1.0%, P = .02), and neonatal referral (15.1% vs 6.5%, P = .008). Among healthy women, abnormal flora was associated with PROM (19.4% vs 7.5%, P = .02) and chorioamnionitis/puerperal infection (11.9% vs 0.8%, P < .001). Among women with GDM, abnormal flora was associated with PROM (32.1% vs 10.0%, P < .001), premature delivery (17.7% vs 6.3%, P = .04), and chorioamnionitis/puerperal infection (32.8% vs 2.5%, P < .001).The vaginal infection rate was higher in patients with GDM compared with healthy pregnant women. GDM and abnormal vaginal flora were both associated with adverse pregnancy outcomes. The vaginal Lactobacillus species were different between the 2 groups, which could contribute to the adverse outcomes.

The vaginal mycobiome: A contemporary perspective on fungi in women's health and diseases

Most of what is known about fungi in the human vagina has come from culture-based studies and phenotypic characterization of single organisms. Though valuable, these approaches have masked the complexity of fungal communities within the vagina. The vaginal mycobiome has become an emerging field of study as genomics tools are increasingly employed and we begin to appreciate the role these fungal communities play in human health and disease. Though vastly outnumbered by its bacterial counterparts, fungi are important constituents of the vaginal ecosystem in many healthy women. Candida albicans, an opportunistic fungal pathogen, colonizes 20% of women without causing any overt symptoms, yet it is one of the leading causes of infectious vaginitis. Understanding its mechanisms of commensalism and patho-genesis are both essential to developing more effective therapies. Describing the interactions between Candida, bacteria (such as Lactobacillus spp.) and other fungi in the vagina is funda-mental to our characterization of the vaginal mycobiome.

Risk of Vaginal Infections at Early Gestation in Patients with Diabetic Conditions during Pregnancy: A Retrospective Cohort Study

Pregnant women with gestational diabetes mellitus (GDM) are reported to be at increased risk for infections of the genital tract. This study aimed to compare the prevalence of asymptomatic bacterial vaginosis (BV) and Candida colonization at early gestation between pregnant women with and without diabetic conditions during pregnancy. We included data from 8, 486 singleton pregnancies that underwent an antenatal infection screen-and-treat programme at our department. All women with GDM or pre-existing diabetes were retrospectively assigned to the diabetic group (DIAB), whereas non-diabetic women served as controls (CON). Prevalence for BV and Candida colonization was 9% and 14% in the DIAB group, and 9% and 13% in the CON group, respectively (n.s.). No significant difference regarding stillbirth and preterm delivery (PTD), defined as a delivery earlier than 37 + 0 (37 weeks plus 0 days) weeks of gestation was found. We could not find an increased risk of colonization with vaginal pathogens at early gestation in pregnant women with diabetes, compared to non-diabetic women. Large prospective studies are needed to evaluate the long-term risk of colonization with vaginal pathogens during the course of pregnancy in these women.

Characterization of the vaginal fungal flora in pregnant diabetic women by 18S rRNA sequencing

Pregnancy and diabetes are regarded as individual risk factors for vaginal candidiasis. The high prevalence of vaginal candidiasis in pregnant diabetic women can be explained by disruption of the balance of the vaginal normal flora. However, little is known about the overall structure and composition of the vaginal fungal flora in pregnant diabetic women. In the present study, the diversity and richness of the vaginal fungal flora in healthy non-pregnant women (group HN), healthy pregnant women (group HP), women with gestational diabetes mellitus (group GDM), and pregnant women with diabetes mellitus type I (group T1DM) were investigated using an 18S rRNA gene clone library method. Our data demonstrated that the composition of the vaginal fungal flora in the four groups could be divided into two phyla (Ascomycetes, 20/26, and Basidiomycetes, 6/26). The most predominant vaginal fungal species belonged to the Candida and Saccharomyces genera, uncultured fungi, and a large number of low-abundance taxa that were unrecorded or underrepresented in previous studies using cultivation-dependent methods. Variation in operational taxonomic units (OTUs) between the study cohorts was generally high in the clone libraries, as 9, 13, 17, and 20 phylotypes were identified in groups HN, HP, GDM, and T1DM, respectively. The Shannon indices of groups GDM and T1DM (with poorer glycemic control) were significantly higher compared to groups HN and HP (p < 0.05). The data presented here revealed an increased diversity and varied composition of the vaginal fungal flora in pregnant diabetic women and demonstrated that poor glycemic control might be associated with disturbances in the vaginal fungal flora.

Lower circulating levels of complement split proteins C3a and C4a in maternal plasma of women with gestational diabetes mellitus

AIM

The aim of this study was to determine the effect of gestational diabetes mellitus on maternal circulating levels of C3a, C4a and C5a.

METHODS

Anaphylatoxin C3a, C4a and C5a levels were measured in maternal and cord plasma from 42 women with normal glucose tolerance and 40 women with gestational diabetes at the time of term elective Caesarean section. Maternal plasma C3a, C4a and C5a concentrations were determined by enzyme-linked immunoassay.

RESULTS

Maternal C3a and C4a concentrations were significantly lower in women with gestational diabetes compared with women with normal glucose tolerance at the time of term delivery (P < 0.05, Student's t-test). There was, however, no difference in maternal circulating C5a levels between the two groups. Additionally, there was no difference in C3a, C4a and C5a levels in cord plasma obtained from women with normal glucose tolerance and those with gesational diabetes. However, a significant positive correlation was observed between maternal and cord complement split levels.

CONCLUSIONS

Gestational diabetes is characterized by lower levels of C3a and C4a in the maternal circulation at the time of term Caesarean delivery.

An evaluation of risk factors in pregnant women with Candida vaginitis and the diagnostic value of simultaneous vaginal and rectal sampling

In this study, we investigated the epidemiological characteristics of VVC among pregnant women. We conducted a prospective survey among 372 pregnant women to investigate the prevalence, clinical forms, etiological agents, and predisposing factors of VVC. In addition, we determined the relationship between vaginal and rectal flora by simultaneously obtaining one high vaginal swab and one rectal swab from each patient using sterile cotton-tipped swabs. Furthermore, we compared the recovery and identification performances of chromID Candida agar to Sabouraud dextrose agar with gentamicin and chloramphenicol. Clinically and mycologically confirmed cases of VVC were detected in 139 (37.4%) and vaginal colonization described in 42 (11.3%) of 372 pregnant women. Rectal cultures were also positive in 98 of the 139 (70.5%) VVC cases. Candida albicans and C. glabrata were identified in vaginal samples in 58.0 versus 19.0% and from rectal samples in 49.0 versus 13.5%, respectively. Increases in gestational week and gravidae were identified to be statistically significant in patients with acute VVC (AVVC) and symptomatic recurrent VVC (RVVC), and asymptomatic RVVC (P = 0.04 and P = 0.03, respectively). In the laboratory diagnosis of VVC, specifically tailored chromogenic media are reliable tools for both the recovery and rapid identification of common Candida spp., particularly C. albicans, as well as for the detection of polyfungal populations in vaginal samples (P > 0.05). In addition, rectal colonization is a common finding in cases of AVVC and symptomatic-RVVC cases and corresponds well with the presence of the same yeast species in the vagina.

Activity of hydrolytic enzymes in fungi isolated from diabetic pregnant women: is there any relationship between fungal alkaline and acid phosphatase activity and glycemic control?

Ability to respond to environmental changes and secretion of hydrolases are considered to be important for Candida virulence. In this study we determined and compared the activities of 19 different hydrolases of the fungal strains isolated from diabetic and non-diabetic pregnant women. We also looked for the presence of a relationship between hydrolase activities and glycemic control, and, furthermore, evaluated the influence of gestational age on the activity of hydrolases. Mycological examinations were performed for 119 diabetic pregnant women: 47 with diabetes mellitus type I (DM), 72 with gestational diabetes (GDM), and for 132 healthy women (CON). Samples were collected from the vagina, rectum and oral cavity and cultured on Sabouraud media. The fungal hydrolase activities were evaluated using the API ZYM test (bioMerieux). For the 19 different fungal hydrolases tested, 13 activities were present in the isolated fungal strains. The activity of alkaline phosphatase (ALP) in vaginal strains (p=0.028) and acid phosphatase (ACP) in strains from the vagina (p=0.006) and rectum (p=0.049) was significantly lower in DM than in GDM and CON women. In conclusion, we describe for the first time that fungi isolated from pregnant diabetic women have lower activity of both phosphatases compared to fungi isolated from healthy women. Furthermore, similar differences of mean ALP and ACP activities were observed in the course of pregnancy in strains from the vagina and rectum of DM and CON women. However, strains from DM had lower activity at each stage of pregnancy. The highest activity of ALP and ACP was detected at the beginning, then declined, and had the lowest values between the 24(th) and 33(rd) week of gestation. After that period the activity of both phosphatases increased.

Candida vulvovaginitis in pregnancy

In the absence of epidemiologic studies over many decades, there are scant data on the prevalence and natural history of vaginal colonization and symptomatic Candida infections in pregnant women. The hormonal mileau of the vagina during pregnancy undoubtedly enhances Candida colonization and serves as a risk factor for symptomatic expression; however, the frequency, clinical manifestation, and response to therapy is largely based on empiric diagnosis of unsubstantiated disease. For reasons of liability, pregnant women have been largely excluded from controlled clinical treatment studies by the pharmaceutical industry; accordingly, treatment guidelines are dictated by opinions rather than data. As in nongravid women, management of symptomatic pregnant women should be based on confirmed diagnosis and not clinical impression.