The effect of maternal flora onCandidacolonisation in the neonate

Multilocus sequence typing of Candida albicans oral isolates reveals high genetic relatedness of mother-child dyads in early life

Candida albicans is a pathogenic fungus recently recognized for its role in severe early childhood caries development (S-ECC). C. albicans oral colonization begins at birth, but the extent of the mother's involvement in yeast transmission to their children is unclear, therefore, this study used a prospective mother-infant cohort to investigate the maternal contribution of C. albicans oral colonization in early life. Oral samples were collected from 160 mother-child dyads during pregnancy and from birth to two years of life. We used whole-genome sequencing to obtain the genetic information of C. albicans isolates and examined the genetic relatedness of C. albicans between mothers and their children using Multilocus Sequence Typing. Multivariate statistical methods were used to identify factors associated with C. albicans' acquisition (horizontal and vertical transmissions). Overall, 227 C. albicans oral isolates were obtained from 93 (58.1%) of mother-child pairs. eBURST analysis revealed 16 clonal complexes, and UPGMA analysis identified 6 clades, with clade 1 being the most populated 124 isolates (54.6%). Significantly, 94% of mothers and children with oral C. albicans had highly genetically related strains, highlighting a strong maternal influence on children's C. albicans acquisition. Although factors such as race, ethnicity, delivery method, and feeding behaviors did not show a significant association with C. albicans vertical transmission, the mother's oral hygiene status reflected by plaque index (PI) emerged as a significant factor; Mothers with higher dental plaque accumulation (PI >=2) had a significantly increased risk of vertically transmitting C. albicans to their infants [odds ratio (95% confidence interval) of 8.02 (1.21, 53.24), p=0.03]. Furthermore, Black infants and those who attended daycare had an elevated risk of acquiring C. albicans through horizontal transmission (p <0.01). These findings highlight the substantial role of maternal transmission in the oral acquisition of C. albicans during early life. Incorporating screening for maternal fungal oral carriage and implementing oral health education programs during the perinatal stage may prove valuable in preventing fungal transmission in early infancy.

11-deoxycortisol positively correlates with T cell immune traits in physiological conditions

BACKGROUND

Endogenous steroid hormones have significant effects on inflammatory and immune processes, but the immunological activities of steroidogenesis precursors remain largely unexplored.

METHODS

We conducted a systematic approach to examine the association between steroid hormones profile and immune traits in a cohort of 534 healthy volunteers. Serum concentrations of steroid hormones and their precursors (cortisol, progesterone, testosterone, androstenedione, 11-deoxycortisol and 17-OH progesterone) were determined by liquid chromatography-tandem mass spectrometry. Immune traits were evaluated by quantifying cellular composition of the circulating immune system and ex vivo cytokine responses elicited by major human pathogens and microbial ligands. An independent cohort of 321 individuals was used for validation, followed by in vitro validation experiments.

FINDINGS

We observed a positive association between 11-deoxycortisol and lymphoid cellular subsets numbers and function (especially IL-17 response). The association with lymphoid cellularity was validated in an independent validation cohort. In vitro experiments showed that, as compared to androstenedione and 17-OH progesterone, 11-deoxycortisol promoted T cell proliferation and Candida-induced Th17 polarization at physiologically relevant concentrations. Functionally, 11-deoxycortisol-treated T cells displayed a more activated phenotype (PD-L1high CD25high CD62Llow CD127low) in response to CD3/CD28 co-stimulation, and downregulated expression of T-bet nuclear transcription factor.

INTERPRETATION

Our findings suggest a positive association between 11-deoxycortisol and T-cell function under physiological conditions. Further investigation is needed to explore the potential mechanisms and clinical implications.

FUNDING

Found in acknowledgements.

Association between prenatal antimicrobial use and offspring attention deficit hyperactivity disorder

BACKGROUND

Gut-brain cross-talk may play an important role in modulating neurodevelopment. Few studies have examined the association between antimicrobials that influence infant gut microbiota assemblage and attention deficit hyperactivity disorder (ADHD).

OBJECTIVE

To examine the association between maternal prenatal antimicrobial use and ADHD in offspring at 10 years of age.

METHODS

Data are from the Wayne County Health, Environment, Allergy and Asthma Longitudinal Study, a racially and socioeconomically diverse birth cohort in metropolitan Detroit, Michigan. Maternal antimicrobial use was extracted from the medical record. ADHD diagnoses were based on parental report at the 10-year study visit. Poisson regression models with robust error variance were used to calculate risk ratios (RR). Cumulative frequency of exposure to antibiotics, and effect modification were also evaluated.

RESULTS

Among the 555 children included in the analysis, 108 were diagnosed with ADHD. During pregnancy, 54.1% of mothers used antibiotics while 18.7% used antifungals. Overall, there was no evidence of an association between prenatal antibiotic exposure and ADHD (RR [95% CI] = 0.98 [0.75, 1.29]), but there was an increased risk of ADHD among those with mothers using 3+ courses of antibiotics (RR [95%CI] = 1.58 [1.10, 2.29]). Prenatal exposure to antifungals was associated with a 1.6 times higher risk of ADHD (RR [95% CI] = 1.60 [1.19, 2.15]). In examining effect modification by child sex for antifungal use, there was no evidence of an association among females (RR [95% CI] = 0.97 [0.42, 2.23]), but among males, prenatal antifungal use was associated with 1.82 times higher risk of ADHD (RR [95% CI] = 1.82 [1.29, 2.56]).

CONCLUSIONS

Maternal prenatal antifungal use and frequent prenatal antibiotic use are associated with an increased risk of ADHD in offspring at age 10. These findings highlight the importance of the prenatal environment and the need for careful use of antimicrobials.

Vulvovaginal yeast infections during pregnancy and perinatal outcomes: systematic review and meta-analysis

BACKGROUND

Vulvovaginal yeast infections in pregnancy are common and can cause extensive inflammation, which could contribute to adverse pregnancy outcomes. Symptomatic yeast infections are likely to cause more inflammation than asymptomatic. The objective of this study was to investigate associations between symptomatic and asymptomatic vulvovaginal yeast infections in pregnancy and perinatal outcomes.

METHODS

We did a systematic review and searched eight databases until 01 July 2022. We included studies reporting on pregnant women with and without laboratory confirmed vulvovaginal yeast infection and preterm birth or eight other perinatal outcomes. We used random effects meta-analysis to calculate summary odds ratios (OR), 95% confidence intervals (CI) and prediction intervals for the association between yeast infection and outcomes. We described findings from studies with multivariable analyses. We assessed the risk of bias using published tools.

RESULTS

We screened 3909 references and included 57 studies. Only 22/57 studies reported information about participant vulvovaginal symptoms. Preterm birth was an outcome in 35/57 studies (49,161 women). In 32/35 studies with available data, the summary OR from univariable analyses was 1.01 (95% CI 0.84-1.21, I2 60%, prediction interval 0.45-2.23). In analyses stratified by symptom status, we found ORs of 1.44 (95% CI 0.92-2.26) in two studies with ≥ 50% symptomatic participants, 0.84 (95% CI 0.45-1.58) in seven studies with < 50% symptomatic participants, and 1.12 (95% CI 0.94-1.35) in four studies with asymptomatic participants. In three studies with multivariable analysis, adjusted ORs were greater than one but CIs were compatible with there being no association. We did not find associations between vulvovaginal yeast infection and any secondary outcome. Most studies were at high risk of bias in at least one domain and only three studies controlled for confounding.

CONCLUSIONS

We did not find strong statistical evidence of an increased risk for preterm birth or eight other adverse perinatal outcomes, in pregnant women with either symptomatic or asymptomatic vulvovaginal yeast infection. The available evidence is insufficient to make recommendations about testing and treatment of vulvovaginal yeast infection in pregnancy. Future studies should assess vulvovaginal symptoms, yeast organism loads, concomitant vaginal or cervical infections, and microbiota using state-of-the-art diagnostics.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42020197564.

Invasive fungal infection is associated with antibiotic exposure in preterm infants: a multi-centre prospective case-control study

BACKGROUND

Previous antibiotic exposure is an important risk factor for invasive fungal infection (IFI). Antibiotic overexposure is common in lower-income countries; however, multi-centre studies concerning IFI in relation to antibiotic exposure are scarce.

AIM

This prospective, multi-centre matched case-control study explored the correlation of IFI and antibiotic exposure in very preterm infants or very-low-birthweight infants admitted to 23 tertiary hospitals in China between 2018 and 2021.

METHODS

Using a 1:2 matched design for gestational age, birth weight and early-onset sepsis (yes/no), the risk factors between infants diagnosed with IFI and infection-free controls were compared. The antibiotic use rate (AUR) was calculated using calendar days of antibiotic therapy in the 4 weeks preceding IFI onset divided by onset day of IFI.

FINDINGS

In total, 6368 infants were included in the study, of which 90 (1.4%) were diagnosed with IFI. Median AUR, length of antibiotic therapy (LOT) and days of antibiotic therapy (DOT) within the 4 weeks preceding IFI onset were 0.90, 18 days and 30 days, respectively. Multi-variate analysis showed that a 10% increase in AUR, each additional day of DOT and LOT, and each additional day of third-generation cephalosporins and carbapenems were notably associated with IFI.

CONCLUSION

Prolonged antibiotic therapy is common before the onset of IFI, and is an important risk factor, especially the use of third-generation cephalosporins and carbapenems. Antibiotic stewardship should be urgently developed and promoted for preterm infants in order to reduce IFI in lower-income countries such as China.

Vertical Transmission and Antifungal Susceptibility Profile of Yeast Isolates from the Oral Cavity, Gut, and Breastmilk of Mother-Child Pairs in Early Life

Yeast acquisition begins at birth; however, the contribution of the mother on yeast transmission to the offspring and associated resistance is yet to be clarified. The aim of this study was to explore the vertical transmission of yeasts and their antifungal susceptibility profile in early life. Oral, fecal, and breastmilk samples were collected from 73 mother-child pairs four to twelve weeks after delivery and cultured on Sabouraud dextrose agar with chloramphenicol. The isolates were identified by MALDI-TOF MS. The vertical transmission was studied by microsatellite genotyping. Antifungal susceptibility was determined for fluconazole, voriconazole, miconazole, anidulafungin, and nystatin by broth microdilution assay, following CLSI-M60 guidelines. A total of 129 isolates were identified from 53% mother-child pairs. We verified the vertical transmission of Candida albicans (n = three mother-child pairs) and Candida parapsilosis (n = one mother-child pair) strains, including an antifungal resistant strain transmitted from breastmilk to the gut of a child. Most isolates were susceptible to the tested antifungals, with the exception of four C. albicans isolates and one R. mucilaginosa isolate. The vertical transmission of yeasts happens in early life. This is the first work that demonstrated the role of the mother as a source of transmission of antifungal-resistant yeasts to the child.

Neonatal invasive candidiasis: updates on clinical management and prevention

Neonatal invasive candidiasis is an important cause of morbidity and mortality in preterm infants. The incidence of invasive candidiasis in this population has been declining in high-income settings, largely due to preventive measures, although there are still considerable variations in incidence between health-care centres. Surveillance data and large, multicentre studies in lower-income settings are not available, although preventive measures in these settings have been shown to decrease the incidence of neonatal invasive candidiasis. Understanding risk factors and pathogenesis are key to the prevention of invasive candidiasis. The difficulty of a definitive diagnosis of invasive candidiasis and the high risk for death or substantial neurodevelopmental impairment, even with appropriate treatment, further increase the need for effective preventive measures. In this Review, we examine the pathogenesis, clinical presentation, and diagnosis of invasive candidiasis. We highlight commonly used and emerging preventive and prophylactic measures, including standardised central line care, antibiotic stewardship, antifungal prophylaxis, and probiotics. Finally, we provide updates on empirical treatment, clinical management in confirmed cases of invasive candidiasis, and antifungal pharmacotherapy.

The impact of the Fungus-Host-Microbiota interplay upon Candida albicans infections: current knowledge and new perspectives

Candida albicans is a major fungal pathogen of humans. It exists as a commensal in the oral cavity, gut or genital tract of most individuals, constrained by the local microbiota, epithelial barriers and immune defences. Their perturbation can lead to fungal outgrowth and the development of mucosal infections such as oropharyngeal or vulvovaginal candidiasis, and patients with compromised immunity are susceptible to life-threatening systemic infections. The importance of the interplay between fungus, host and microbiota in driving the transition from C. albicans commensalism to pathogenicity is widely appreciated. However, the complexity of these interactions, and the significant impact of fungal, host and microbiota variability upon disease severity and outcome, are less well understood. Therefore, we summarise the features of the fungus that promote infection, and how genetic variation between clinical isolates influences pathogenicity. We discuss antifungal immunity, how this differs between mucosae, and how individual variation influences a person's susceptibility to infection. Also, we describe factors that influence the composition of gut, oral and vaginal microbiotas, and how these affect fungal colonisation and antifungal immunity. We argue that a detailed understanding of these variables, which underlie fungal-host-microbiota interactions, will present opportunities for directed antifungal therapies that benefit vulnerable patients.

Acquisition and establishment of the oral microbiota

Acquisition and establishment of the oral microbiota occur in a dynamic process over various stages and involve close and continuous interactions with the host and its environment. In the present review, we discuss the stages of this process in chronological order. We start with the prenatal period and address the following questions: ‘Is the fetus exposed to maternal microbiota during pregnancy?’ and ‘If so, what is the potential role of this exposure?’ We comment on recent reports of finding bacterial DNA in placenta during pregnancies, and provide current views on the potential functions of prenatal microbial encounters. Next, we discuss the physiological adaptations that take place in the newborn during the birth process and the effect of this phase of life on the acquisition of the oral microbiota. Is it really just exposure to maternal vaginal microbes that results in the difference between vaginally and Cesarian section‐born infants? Then, we review the postnatal phase, in which we focus on transmission of microbes, the intraoral niche specificity, the effects of the host behavior and environment, as well as the role of genetic background of the host on shaping the oral microbial ecosystem. We discuss the changes in oral microbiota during the transition from deciduous to permanent dentition and during puberty. We also address the finite knowledge on colonization of the oral cavity by microbes other than the bacterial component. Finally, we identify the main outstanding questions that limit our understanding of the acquisition and establishment of a healthy microbiome at an individual level.

Diet Influences the Oral Microbiota of Infants during the First Six Months of Life

Background: Oral microorganisms contribute to oral health and disease, but few have studied how infant feeding methods affect their establishment. Methods: Infant (n = 12) feeding records and tongue and cheek swabs were collected within 48 h of birth, and after 2, 4, and 6 mo. DNA was extracted from samples, bacterial and fungal amplicons were generated and sequenced using Illumina MiSeq, and sequences were analyzed using Quantitative Insights Into Microbial Ecology (QIIME) and Statistical Analysis System (SAS) to evaluate differences over time and among breast-fed, formula-fed, mixed-fed, and solid food-fed infants. Results: Considering all time points, breast milk- and mixed-fed infants had lower oral species richness than solid food-fed infants (p = 0.006). Regardless of feeding mode, species richness was lower at birth than at other time points (p = 0.006). Principal coordinates analysis (PCoA) of unique fraction metric (UniFrac) distances indicated that bacterial communities were impacted by feeding method (p < 0.005). Considering all time points, breast-fed infants had higher Streptococcus, while formula-fed infants had higher Actinomyces and Prevotella. Regardless of feeding mode, Propionibacterium, Porphyromonas, Prevotella, Gemella, Granulicatella, Veillonella, Fusobacterium, Leptotrichia, Neisseria, and Haemophilus increased with age, while Cloacibacterium and Dechloromonas decreased with age. Oral fungi were detected in infants but were not impacted by diet. Conclusions: These findings demonstrate that the establishment of oral bacteria depends on dietary composition and age. More research is necessary to determine whether this affects risk of oral caries and other health outcomes later in life.

Mycobiota of the human gastrointestinal tract

Fungi (Mycota) that colonize the human digestive tract are collectively referred to as gastrointestinal mycobiota. The most common method of fungi identification is based on the culture of a clinical sample with subsequent classic phenotypic identification detailed by biochemical and/or molecular (e.g. sequencing of ITS regions of rDNA) tests in some cases. Additionally, the culture-independent identification is gaining popularity, especially in scientific research. The composition of the human mycobiota significantly differs across the digestive tract. In the oral cavity of healthy people, <i>Candida</i>, <i>Cladosporium</i>, <i>Auerobasidium</i>, and <i>Aspergillus</i> are most often identified fungi genera; however, in recent studies the presence of Malassezia spp. has been also emphasized. In the case of the lower gastrointestinal tract, <i>Candida</i>, <i>Saccharomyces</i>, <i>Penicillium</i>, <i>Aspergillus</i>, <i>Cryptococcus</i>, <i>Malassezia</i>, <i>Cladosporium</i>, <i>Galactomyces</i>, <i>Debaryomyces</i>, and <i>Trichosporon</i> genera are most often reported. This paper summarizes the factors that are associated with the composition of mycobiota in both children (age, type of delivery, breastfeeding) and adults (age, gender, diet, saliva flow rate and composition). Changes in the composition of mycobiota also occur in pathological conditions, including both gastrointestinal diseases (Crohn’s disease, oral lichen planus) and metabolic diseases (diabetes, obesity). Additionally, this paper summarizes the already known, putative interactions between fungi and bacteria colonizing the human digestive tract.

Molecular Identification of Candida Species in the Oral Microbiota of Individuals with Down Syndrome: A Case-Control Study

Candida species are common in the human oral microbiota and may cause oral candidiasis (OC) when the microbiota equilibrium is disturbed. Immunosuppressed individuals are susceptible to oral infections as individuals with Down syndrome (IDS) due to particularities of their mouth morphoanatomy, saliva and comorbidities. This study aimed to analyze the molecular epidemiology of Candida spp. from the oral cavity of IDS and their relatives. A case-control study with 80 IDS and 80 non-syndromic (non-DS) was evaluated by oral swab collection for culture on Sabouraud dextrose agar, selection of yeast colonies to Gram staining and culturing on chromogenic media. DNA extraction was performed with the phenol/chloroform method for screening of 6 Candida species medically important in PCR, applying SPSS for statistics. We confirmed four species in 46 IDS without use of antimicrobials (57.54%), with a high prevalence of C. albicans/Ca (93.48%/43) and 3 C. glabrata/Cg (6.52%), being 25 of these IDS (31.25%) colonized by species other than C. albicans: Ca + Cg (16), Ca + C. tropicalis/Ct (7) and Ca + C. krusei/Ck (2). Only 10 non-DS were colonized by one species (11.25%): 6 C. albicans, 2 C. glabrata, 1 C. tropicalis and 1 C. krusei. Previous OC was reported by 39 IDS (48.75%), being 33 positives for Candida spp. (84.61%) and 17 with active OC (21.25%). Five non-DS reported OC previously and had no active lesions. Behavioral changes and buccal health programs directed to IDS may help prevent OC and its recurrence, providing information on oral hygiene for self-care.

Oral microbiome: possible harbinger for children's health

The human microbiome functions as an intricate and coordinated microbial network, residing throughout the mucosal surfaces of the skin, oral cavity, gastrointestinal tract, respiratory tract, and reproductive system. The oral microbiome encompasses a highly diverse microbiota, consisting of over 700 microorganisms, including bacteria, fungi, and viruses. As our understanding of the relationship between the oral microbiome and human health has evolved, we have identified a diverse array of oral and systemic diseases associated with this microbial community, including but not limited to caries, periodontal diseases, oral cancer, colorectal cancer, pancreatic cancer, and inflammatory bowel syndrome. The potential predictive relationship between the oral microbiota and these human diseases suggests that the oral cavity is an ideal site for disease diagnosis and development of rapid point-of-care tests. The oral cavity is easily accessible with a non-invasive collection of biological samples. We can envision a future where early life salivary diagnostic tools will be used to predict and prevent future disease via analyzing and shaping the infant’s oral microbiome. In this review, we present evidence for the establishment of the oral microbiome during early childhood, the capability of using childhood oral microbiome to predict future oral and systemic diseases, and the limitations of the current evidence.

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.

Influence of delivery and feeding mode in oral fungi colonization - a systematic review

Postnatal acquisition of microorganisms from maternal and environmental sources contributes to the child microbiome development. Several studies showed that the mode of delivery and breastfeeding may have impact on the oral bacterial colonization, however, the influence on oral fungal colonization is still unknown. We performed a systematic literature review on mother to child oral fungi transmission, namely regarding the association between the mode of delivery and breastfeeding in oral yeast colonization. Our analysis revealed no significant differences between the oral mycobiome of breastfed and bottle-fed children. As for the delivery mode, the majority of studies found a relation between fungal colonization and vaginal delivery. Candida albicans was the most commonly isolated fungi species. Our analysis suggests that maternal breastfeeding does not seem to influence oral mycology, but vaginal delivery appears to promote oral yeast colonization in early life.

Neonatal thrush of newborns: Oral candidiasis?

Objectives

Neonatal thrush, also called oral candidiasis, is commonly a clinical diagnosis based on white patches on oral mucosal surfaces. Candida albicans is often associated with it. This clinical study aimed to investigate the presence of C. albicans among newborns with or without clinical findings of candidiasis on oral mucosa. Another aim was to investigate how thrush responded to current therapy by acidic liquids such as lingonberry or lemon juice.

Material and methods

Swipe samples were collected from 32 healthy, full‐term infants younger than 12 months with or without white patches on oral mucosa. Clinical diagnosis of thrush was made by a community nurse based on thick and yellowish white patches. The routine therapy was oral lingonberry or lemon juice or soda water. Disappearing of patches was controlled by a phone call about 2 weeks after the baseline. Both parents and nurses gave background factors by filling a questionnaire.

Results

One (3%) infant without clinical signs was diagnosed with Candida parapsilosis, none with C. albicans. Thrush resembling candidiasis was diagnosed clinically in four (12.5%) children. Three out of four parents reported persisting findings after 2 weeks. Only the maternal mastitis and use of antibiotics were significantly associated with thrush (p = .001). C. albicans was not discovered from babies with clinical thrush.

Conclusions

Aetiology of the white patches remained unclear. The current way of treating them with acidic liquids is not efficient. Additional studies are needed.

Human Anti-fungal Th17 Immunity and Pathology Rely on Cross-Reactivity against Candida albicans

Th17 cells provide protection at barrier tissues but may also contribute to immune pathology. The relevance and induction mechanisms of pathologic Th17 responses in humans are poorly understood. Here, we identify the mucocutaneous pathobiont Candida albicans as the major direct inducer of human anti-fungal Th17 cells. Th17 cells directed against other fungi are induced by cross-reactivity to C. albicans. Intestinal inflammation expands total C. albicans and cross-reactive Th17 cells. Strikingly, Th17 cells cross-reactive to the airborne fungus Aspergillus fumigatus are selectively activated and expanded in patients with airway inflammation, especially during acute allergic bronchopulmonary aspergillosis. This indicates a direct link between protective intestinal Th17 responses against C. albicans and lung inflammation caused by airborne fungi. We identify heterologous immunity to a single, ubiquitous member of the microbiota as a central mechanism for systemic induction of human anti-fungal Th17 responses and as a potential risk factor for pulmonary inflammatory diseases.

Biological Roles of Protein-Coding Tandem Repeats in the Yeast Candida Albicans

Tandem repeat (TR) DNA mutates faster than other DNA by insertion and deletion of repeats. Large parts of eukaryotic proteomes are encoded by ORFs containing protein-coding TRs (TR-ORFs, pcTRs) with largely unknown biological consequences. We explored these in the yeast Candida albicans, an opportunistic human pathogen. We found that almost half of C. albicans’ proteins are encoded by TR-ORFs. pcTR frequency differed only moderately between different gene (GO) categories. Bioinformatic predictions of genome-wide mutation rates and clade-specific differences in pcTR allele frequencies indicated that pcTRs (i) significantly increase the genome-wide mutation rate; (ii) significantly impact on fitness and (iii) allow the evolution of selectively advantageous clade-specific protein variants. Synonymous mutations reduced the repetitiveness of many amino acid repeat-encoding pcTRs. A survey, in 58 strains, revealed that in some pcTR regions in which repetitiveness was not significantly diminished by synonymous mutations the habitat predicted which alleles were present, suggesting roles of pcTR mutation in short-term adaptation and pathogenesis. In C. albicans pcTR mutation apparently is an important mechanism for mutational advance and possibly also rapid adaptation, with synonymous mutations providing a mechanism for adjusting mutation rates of individual pcTRs. Analyses of Arabidopsis and human pcTRs showed that the latter also occurs in other eukaryotes.

Retrospective Analysis of Candida-related Conditions in Infancy and Early Childhood Caries

PURPOSE

The purpose of this study was to assess whether there is an association between oral thrush or other Candida-related conditions in infancy and early childhood caries (ECC) diagnosed by pediatricians.

METHODS

We conducted a retrospective cohort study using electronic health records from six national children's hospitals that participate in the PEDSnet research network. There were 1,012,668 children with a visit at ages one to 12 months and another visit at ages 13 to 71 months. The independent variables were diagnosis of thrush or Candida-related conditions in the first year of life, while the dependent variable was diagnosis of ECC between 13 to 71 months old.

RESULTS

Oral thrush detection was strongly associated with ECC, particularly between 13 and 36 months (rate ratio between 2.7 [95 percent confidence interval (95% CI) equals 2.5 to 2.9; P<.001] and 3.0 [95% CI, equals 2.8 to 3.4; P<.001]). A similar trend was observed with other Candida-related conditions.

CONCLUSIONS

Oral thrush may be a risk factor for early childhood caries.

Association Between Candiduria and Candidemia: A Clinical and Molecular Analysis of Cases

The risk of developing candidemia after candiduria is reportedly very low, but it has not been adequately investigated. The aim of this study was to examine the molecular relatedness between Candida strains isolated from adult patients with candidemia and concomitant candiduria in association with the clinical characteristics of the cases. All episodes of candidemia occurring in a tertiary care academic hospital during a 5-year period were recorded prospectively. Patients with episodes of candiduria occurring two weeks preceding to or one week following a positive for Candida blood culture were included in the study. The genotypic relatedness of Candida strains isolated from blood and urine was investigated by pulsed-field gel electrophoresis after digestion with the BssHII restriction endonuclease. We recorded 141 candidemia episodes, occurring in 134 patients. Twelve episodes of candidemia with concomitant candiduria occurred in 11 patients (8% of all candidemias). In six of these episodes, the strains in the blood-urine pairs belonged to different species. In two episodes, the isolates belonged to the same species but were not genetically related, and only in four (2.8% of all candidemias), the strains were related. All four patients were severely ill and had multiple risk factors for candidemia. These findings indicate that in hospitalized patients with candidemia, concomitant candiduria is rare and usually an independent event, confirming previous reports. In the critically ill, however, the existence of genetically related strains in blood and urine appears to be more frequent, with more probable the hematogenous dissemination.

Antifungal Immunological Defenses in Newborns

Newborns are prone to fungal infections, largely due to Candida species. The immunological basis for this vulnerability is not yet fully understood. However, useful insights can be gained from the knowledge of the maturation of immune pathways during ontogeny, particularly when placed in context with how rare genetic mutations in humans predispose to fungal diseases. In this article, we review these most current data on immune functions in human newborns, highlighting pathways most relevant to the response to Candida. While discussing these data, we propose a framework of why deficiencies in these pathways make newborns particularly vulnerable to this opportunistic pathogen.

The relationship of Candida colonization of the oral and vaginal mucosae of mothers and oral mucosae of their newborns at birth

OBJECTIVE

Vaginal Candida colonization is common during pregnancy. Vaginal Candida may transmit vertically to the mouth of newborns during labor. The aim of this study was to assess and compare oral Candida colonization between vaginally born newborns and cesarean-born newborns and to investigate the association of the mother's vaginal and oral Candida colonization and the newborn's oral colonization at the time of delivery.

STUDY DESIGN

Culture swabs were collected from the oral and vaginal mucosae of 100 pregnant women and from the oral mucosa of their 100 full-term newborns. Fifty (50%) of the mothers gave birth vaginally and the other 50 (50%) by cesarean section.

RESULTS

The prevalence of oral and vaginal Candida in pregnant mothers was 49% and 40%, respectively. Oral Candida colonization in newborns was 7%. Oral Candida was isolated from 5 of 50 (10%) in the vaginally born group and from 2 of 50 (4%) in the cesarean-born group (P = .44). In vaginally born group, oral Candida was isolated from 5 of 20 (25%) in those born to mothers with vaginal colonization of Candida, and 0 of 30 (0.0%) in mothers without vaginal colonization of Candida (P = .007).

CONCLUSIONS

The mother's vaginal Candida may constitute an important source of oral Candida in the newborns, particularly in those delivered vaginally.

Vulvovaginal Candidiasis in Pregnant Women and its Importance for Candida Colonization of Newborns

Vulvovaginal candidiasis is the second most common cause of vaginitis worldwide (after bacterial candidiasis). Maternal vulvovaginal candidiasis is a major risk factor for Candida colonization and infection of the infant where prognosis depends on different predisposing factors. The aim of this study was to determine the incidence and the etiological structure of vulvovaginal candidiasis in pregnant women and its impact on Candida colonization of newborns.

MATERIALS AND METHODS

Samples of vaginal secretions from 80 healthy pregnant women who were clinically suspicious for Candida vaginitis were collected within 48 hours before delivery. Samples for probable Candida colonization from the oral mucosa and feces were collected from their newborns within 47-72 hours after birth. Samples were plated on Sabouraud agar, followed by species identification by API Candida yeast assay.

RESULTS

Twenty-three (28.75 ± 5.06%) of the evaluated pregnant women were positive for Candida spp. Positive samples for Candida colonization were found in 18 (22.22 ± 4.62%) of the examined 81 newborns (one pair of twins) from mothers who were clinically suspicious for vaginal candidiasis. Isolates of the newborns were 100% identical to those of the mothers' vaginal secretion. Candida albicans was the predominant species identified in the pregnant women (91.67 ± 0.06%) and in the neonates (83.33±8.78%).

The Oral Microbiome in Health and Its Implication in Oral and Systemic Diseases

The oral microbiome can alter the balance between health and disease, locally and systemically. Within the oral cavity, bacteria, archaea, fungi, protozoa, and viruses may all be found, each having a particular role, but strongly interacting with each other and with the host, in sickness or in health. A description on how colonization occurs and how the oral microbiome dynamically evolves throughout the host's life is given. In this chapter the authors also address oral and nonoral conditions in which oral microorganisms may play a role in the etiology and progression, presenting the up-to-date knowledge on oral dysbiosis as well as the known underlying pathophysiologic mechanisms involving oral microorganisms in each condition. In oral pathology, oral microorganisms are associated with several diseases, namely dental caries, periodontal diseases, endodontic infections, and also oral cancer. In systemic diseases, nonoral infections, adverse pregnancy outcomes, cardiovascular diseases, and diabetes are among the most prevalent pathologies linked with oral cavity microorganisms. The knowledge on how colonization occurs, how oral microbiome coevolves with the host, and how oral microorganisms interact with each other may be a key factor to understand diseases etiology and progression.

Copper-coated textiles: armor against MDR nosocomial pathogens

Soft surfaces in the health-care setting harbor potentially pathogenic bacteria and fungi that can be transferred to patients and personnel. We evaluated the in vitro antimicrobial efficacy of two types of innovative copper-coated textiles against a variety of nosocomial multi-drug resistant (MDR) pathogens. Five isolates each of MDR Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii and Enterococcus faecium as well as three Candida parapsilosis were tested. The antimicrobial activity of copper-coated para-aramide and copper-coated polyester swatches was compared to that of non-copper coated controls using a quantitative method. Reduction of viable colonies by >3log10 from starting inoculum was characterized as bactericidal activity. No viable colonies of S. aureus, P. aeruginosa, E. faecium and C. parapsilosis were recovered after the first hour of contact while for A. baumannii, no viable colonies were recovered after only 15min of contact with either type of copper-coated textiles. Copper-coated para-aramide exhibited a bactericidal effect at 15min of contact with A. baumannii, at 1h with S. aureus, P. aeruginosa, E. faecium and C. parapsilosis and at 3h with K. pneumoniae. Copper-coated polyester was bactericidal at 15min of contact for A. baumannii and at 1h for the other species tested. Both copper-coated textiles exhibited a rapid and significant antimicrobial effect. Antimicrobial textiles may have a role in the arsenal of strategies aiming to reduce environmental contamination in the health-care setting.

Detection of Candida spp. in the vagina of a cohort of nulliparous pregnant women by culture and molecular methods: Is there an association between maternal vaginal and infant oral colonisation?

BACKGROUND

Most studies describing vaginal Candida spp. in pregnancy focus on symptomatic vaginitis, rather than asymptomatic colonisation, and solely utilise microbiological culture. The extent to which asymptomatic vaginal carriage may represent a reservoir for infant oral colonisation has been highly debated.

MATERIALS AND METHODS

This study formed part of the Candida and Staphylococcus Transmission Longitudinal Evaluation (CASTLE) study, in Melbourne, Australia, from 2009 to 2011 and used culture and molecular methods to examine vaginal swabs collected late in the third trimester of pregnancy for Candida spp. Oral swabs from infants were also examined using culture methods.

RESULTS

Overall, 80 of 356 (22%) women were positive for Candida spp; the majority being Candida albicans (83%). Candida glabrata and other Candida spp. were also identified, but in much lower numbers. Molecular analysis identified numerous positive samples not detected by culture, including 13 cases of C. albicans. In addition, some positive samples only recorded to genus level by culture were accurately identified as either C. albicans or C. glabrata following molecular analyses. Eighteen infants recorded positive Candida spp. cultures, predominantly C. albicans. However, there were only four (25%) mother/infant dyads where C. albicans was detected.

CONCLUSIONS

This study provides valuable data on asymptomatic colonisation rates of Candida spp. within an asymptomatic population of women late in pregnancy. The utilisation of molecular methods improved the rate of detection and provided a more accurate means for identification of non-albicans Candida spp. The low mother/infant colonisation rate suggests that non-maternal sources are likely involved in determining infant oral colonisation status.

Prevalence of oral Candida in the first year of life

Colonisation of the gastrointestinal tract is influenced by primary microbial exposure and bioactive factors in breastmilk. The aim was to explore the prevalence of oral Candida in the first year of life in relation to selected exposures. Oral Candida was studied in 100 healthy infants at 4 and 8 weeks, 3, 6 and 12 months of age and related to delivery mode, birth weight, infant health and feeding, antibiotics, antimycotics, steroids and probiotics in mother and infant, living conditions, maternal smoking and infections The association between lactoferrin and antisecretory factor in breastmilk and maternal serum haemoglobin, transferrin, and ferritin levels in relation to oral Candida was also explored. About 11% to 15% of the infants had oral Candida at the respective age. Colonisation was fairly stable until 6 months of age. There was no conclusive impact of the investigated exposures at entry. Infants with a furry pet at home had a lower frequency of Candida at 3 months, (P < 0.05) whereas all but one colonised infant had older siblings at 12 months (P < 0.01). Lactoferrin in breastmilk was negatively associated with colonisation at 6 months of age. It is concluded that 11 to 15% had oral Candida. Exposure to furry pets and siblings impacted oral Candida.