[Contribution of the chromogenic medium CHROMagar(®)Candida in mycological diagnosis of yeasts]

Up-regulation of CDR1 and MDR1 efflux pump genes and fluconazole resistance are involved in recurrence in Candida albicans-induced vulvovaginal candidiasis

Recurrent vulvovaginal candidiasis (RVVC) due to fluconazole resistance in Candida albicans isolates causes a wide range of complications. A number of 63 Candida albicans isolates obtained from vulvovaginal candidiasis (VVC) were identified by Internal Transcribed Spacer-Restriction Fragment Length Polymorphism (ITS-RFLP). Antifungal susceptibility testing was performed by broth microdilution method according to the CLSI protocol. The role of CDR1 and MDR1 genes in progress of VVC to RVVC was examined and the activity of virulence-related enzymes was assessed. Candida albicans was diagnosed in 62.4 % cases, of which 22.2 % were confirmed as RVVC. Voriconazole was the most active drug among five tested antifungals. The mean expression level of CDR1 and MDR1 was higher in RVVC isolates compared to multidrug azole-resistant VVC isolates. Our results demonstrated that the expression of CDR1 and MDR1 and the level of phospholipase and proteinase activities could be quite important to induce fluconazole resistance in C. albicans and to progress of VVC to become RVVC in involved patients.

Frequency of Candida spp. in the Oral Cavity of Asymptomatic Preschool Mexican Children and Its Association with Nutritional Status

Malnutrition is a public health problem in developing countries, affecting the child population, which favors the appearance of infections such as oral candidiasis. In Mexico, information on the presence of oral colonization by Candida spp. in asymptomatic children is scarce. The present study aimed to determine the presence of Candida spp. in the oral cavity of asymptomatic preschool Mexican children and its association with their nutritional status. A sample of oral mucosa was obtained using a sterile swab and then inoculated in Sabouraud dextrose agar with antibiotics, and the yeast growth was phenotypically identified. The anthropometric profile of children was performed based on the guidelines of the International Society for the Advancement of Kinanthropometry. In addition, eating habits were investigated. The possible associations between the variables were determined through the chi-square test (IC95%, p < 0.05) (GraphPad Prism 8.0). Among the 743 assessed children (403 boys and 340 girls), the average age was 4.6 years, and the average nutritional status was normal (53.7%), followed by undernutrition (28.4%), overweight (12.4%) and obesity (5.5%). In 52 children, Candida was isolated, and the identified species were C. albicans (87.8%), C. glabrata (11.5%), C. krusei (5.8%) and C. parapsilosis (1.9%). The frequency of colonization was greater in males of six years (69.23%). There was no significant association between the colonization by Candida spp. and the nutritional status; however, a relation was observed with a high intake of simple carbohydrates.

Microbiological and molecular screening of Candida spp. isolated from genital tract of asymptomatic pregnant women

Introduction. Candida spp. may cause opportunistic infections called vulvovaginal candidiasis (VVC), which is estimated to be the second most common cause of vaginitis worldwide.Gap Statement. Under various circumstances, VVC could compromise pregnancy outcomes. Emerging data suggests that VVC during pregnancy may be associated with increased risk of complications and congenital cutaneous candidiasis.Aim. To assess the prevalence of Candida spp. in asymptomatic pregnant women and determine the susceptibility of the isolates to antifungal drugs.Methodology. In a prospective cohort, 65 high vaginal swab samples of consented pregnant women. Candida isolates were identified using both microbiological and molecular tools and drug susceptibilities were profiled.Results. The prevalence of VVC among our study participants was 37 %, 24 of the 65 asymptomatic pregnant women show Candida spp. colonization. C. albicans was the most common species 61 %, followed by C. glabrata 39 %. In addition, a significant fraction of the isolated colonies showed resistance to Fluconazole, with a ratio of 63 % for C. albicans isolates and 16 % for Candida glabrata isolates. Moreover, relative quantification of genes related to resistance to fluconazole, CDR1, ERG11 as well as HWP1, showed a significant change compared to controls.Conclusion. Monitoring of vaginal Candida colonization before the third trimester of pregnancy, that could reduce congenital Candida colonization and risk of pregnancy complications.

Otomycosis in Africa: Epidemiology, diagnosis and treatment

This review sets out to highlighted knowledge gaps regarding the epidemiological, diagnostic (clinical and laboratory) and therapeutic aspects of otomycosis in Africa. A computerized literature search for otomycosis related articles were performed using MEDLINE. The search encompassed articles published in early January 1980 to May 2019 yielded 220 articles. Electronic search on PubMed was performed with the specific keywords. This review shows the higher prevalence rates of otomycosis in Africa. These prevalences varies from one country to the other and also from one population to another within the same country. The main symptoms are otalgia, otorrhea, hearing loss, aural fullness, pruritus, and tinnitus. Otomycosis is due to several predisposing factors, however, use of topical antibiotic/steroid eardrops, trauma to the external ear canal or instrumentation of the ear, being exposed to hot humid atmospheres, and close contact with water are the common risk factors. Aspergillus species are the most commonly identified organisms compared with Candida species. Worldwide, A. niger and C. albicans are the most commonly described agents of otomycosis in Africa. The Laboratory diagnosis of otomycosis is usually confirmed by mycologic tests relied on a set of evidences. Further conventional methods such as Chromagar Candida System, latex agglutination test, Biochemical tests (Api 20C AuxTM and auxanogram), phenotypical tests (Germ-tube and chlamydosporulation), and rRNA gene sequencing (PCR) are performed to improve diagnosis and the management of the disease. Adequate treatment of otomycosis includes microscopic suction clearance of fungal mass, discontinuation of topical antibiotics and treatment with antifungal eardrops for three weeks.

Mycobiome in the Gut: A Multiperspective Review

Human gut is home to a diverse and complex microbial ecosystem encompassing bacteria, viruses, parasites, fungi, and other microorganisms that have an undisputable role in maintaining good health for the host. Studies on the interplay between microbiota in the gut and various human diseases remain the key focus among many researchers. Nevertheless, advances in sequencing technologies and computational biology have helped us to identify a diversity of fungal community that reside in the gut known as the mycobiome. Although studies on gut mycobiome are still in its infancy, numerous sources have reported its potential role in host homeostasis and disease development. Nonetheless, the actual mechanism of its involvement remains largely unknown and underexplored. Thus, in this review, we attempt to discuss the recent advances in gut mycobiome research from multiple perspectives. This includes understanding the composition of fungal communities in the gut and the involvement of gut mycobiome in host immunity and gut-brain axis. Further, we also discuss on multibiome interactions in the gut with emphasis on fungi-bacteria interaction and the influence of diet in shaping gut mycobiome composition. This review also highlights the relation between fungal metabolites and gut mycobiota in human homeostasis and the role of gut mycobiome in various human diseases. This multiperspective review on gut mycobiome could perhaps shed new light for future studies in the mycobiome research area.

Prevalence and antifungal susceptibility of Candida albicans causing vaginal discharge among pregnant women in Lebanon

Background

Vaginal candidiasis is frequent in pregnant women and is associated with sepsis and adverse neonatal outcomes. This study determined the prevalence of candida species in symptomatic pregnant women and evaluated the antifungal susceptibility profile of the isolated Candida strains. It also aimed to explore whether Candida species predicts gestational complications and adverse neonatal outcomes.

Methods

A total of 258 pregnant women with vaginal discharge at 35 to 37 week of gestation participated in this study. Vaginal swabs from these patients were collected at various obstetrics and gynecology clinics in Lebanon for a period of 14 months. Candida isolates were identified at species level and antifungal susceptibility of Candida albicans to fluconazole (FCZ), amphotericin B (AMB), itraconazole (ICZ) and voriconazole (VCZ) was determined by the agar-based E-test method.

Results

Among 258 women tested, 100 (39%) were positive for Candida species. C. albicans, C. glabrata and C. krusei were isolated from 42, 41 and 17% of the women, respectively. C. albicans was significantly associated only with gestational diabetes while C. krusei or C. glabrata had significant positive associations with other gestational complications. The antifungal susceptibility tests of C. albicans isolates revealed 97.5, 90, 87.5 and 97.5% susceptibility to AMB, FCZ, ICZ and VCZ, respectively.

Conclusion

The current study revealed high incidence of both C. albicans and non-C. albicans Candida strains causing vulvovaginitis among pregnant women in Beirut, Lebanon. Candida screening as antenatal follow up is advised to minimize the risk of adverse neonatal outcome or gestational complications.

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.

HumanMycobiomeScan: a new bioinformatics tool for the characterization of the fungal fraction in metagenomic samples

Background

Modern metagenomic analysis of complex microbial communities produces large amounts of sequence data containing information on the microbiome in terms of bacterial, archaeal, viral and eukaryotic composition. The bioinformatics tools available are mainly devoted to profiling the bacterial and viral fractions and only a few software packages consider fungi. As the human fungal microbiome (human mycobiome) can play an important role in the onset and progression of diseases, a comprehensive description of host-microbiota interactions cannot ignore this component.

Results

HumanMycobiomeScan is a bioinformatics tool for the taxonomic profiling of the mycobiome directly from raw data of next-generation sequencing. The tool uses hierarchical databases of fungi in order to unambiguously assign reads to fungal species more accurately and > 10,000 times faster than other comparable approaches. HumanMycobiomeScan was validated using in silico generated synthetic communities and then applied to metagenomic data, to characterize the intestinal fungal components in subjects adhering to different subsistence strategies.

Conclusions

Although blind to unknown species, HumanMycobiomeScan allows the characterization of the fungal fraction of complex microbial ecosystems with good performance in terms of sample denoising from reads belonging to other microorganisms. HumanMycobiomeScan is most appropriate for well-studied microbiomes, for which most of the fungal species have been fully sequenced. This released version is functionally implemented to work with human-associated microbiota samples. In combination with other microbial profiling tools, HumanMycobiomeScan is a frugal and efficient tool for comprehensive characterization of microbial ecosystems through shotgun metagenomics sequencing.

Electronic supplementary material

The online version of this article (10.1186/s12864-019-5883-y) contains supplementary material, which is available to authorized users.

Forgotten fungi-the gut mycobiome in human health and disease

The human body is home to a complex and diverse microbial ecosystem that plays a central role in host health. This includes a diversity of fungal species that is collectively referred to as our 'mycobiome'. Although research into the mycobiome is still in its infancy, its potential role in human disease is increasingly recognised. Here we review the existing literature available on the human mycobiota with an emphasis on the gut mycobiome, including how fungi interact with the human host and other microbes. In doing so, we provide a comprehensive critique of the methodologies available to research the human mycobiota as well as highlighting the latest research findings from mycological surveys of different groups of interest including infants, obese and inflammatory bowel disease cohorts. This in turn provides new insights and directions for future studies in this burgeoning research area.