Oral Yeast Research Articles

Subgingival Yeasts Species Amongst Smokers and Nonsmokers With Peri-implantitis

There is a dearth of studies that have assessed yeast species in the subgingival biofilm (SB) samples collected from smokers and nonsmokers with peri-implantitis. This study assesses peri-implant clinical and radiographic profiles and yeasts species in the subgingival SB of cigarette smokers and nonsmokers with peri-implantitis. Participants were divided into 3 groups: group 1, cigarette smokers with peri-implantitis; group 2, nonsmokers with peri-implantitis; and group 3, nonsmokers without peri-implantitis. Information on smoking pack-years and patient demographics was collected. Implant-related parameters were retrieved from health care records. Peri-implant modified plaque and gingival indices (mPI and mGI, respectively), probing depth (PD), and crestal bone loss (CBL) were recorded. The SB samples were collected, subgingival yeasts colonisation was recorded, and yeasts species were identified. P < .05 was considered statistically significant. Respectively, 22, 22, and 24 individuals were included in groups 1, 2, and 3. In group 1, cigarette smokers had a smoking history of 29.7 ± 7.9 pack-years. The PD, mPI, and mesial and distal CBL were higher in groups 1 (P < .01) and 2 (P < .01) than in group 3. The mGI was higher in group 2 (P < .01) than in groups 1 and 3. The total number of implants in groups 1, 2, and 3 were 22, 22, and 24, respectively. In group 3, implants were in function for a longer duration (12.2 ± 2.3 years; P < .05) than in groups 1 (5.6 ± 1.9 years) and 2 (5.1 ± 0.7 years). Yeasts levels in CFU/mL were higher in group 1 than in groups 2 (P < .05) and 3 (P < .05); they were also higher in group 2 than in group 3 (P < .05). Candida albicans was the most isolated yeasts species, followed by Candida tropicalis, in all groups. Cigarette smokers and nonsmokers present similar peri-implant clinicoradiographic profiles, and oral yeasts (predominantly C albicans) seem to play a role in the progression of peri-implant disease in these individuals.

Oral Yeasts Carriage in Prediabetic Smokers and Nonsmokers

Habitual smoking and prediabetes are independent risk factors for increased oral yeasts carriage (OYC); however, no studies have compared OYC amongst cigarette smokers and nonsmokers with and without prediabetes. The aim was to fill this research gap. Ninety-two participants were included and categorised into 4 groups: group 1, prediabetic (haemoglobin A1c [HbA1c] levels, 5.7%-6.4%) cigarette smokers; group 2, cigarette smokers without prediabetes; group 3, prediabetic nonsmokers; and group 4, nonsmokers without prediabetes. Patient demographics and HbA1c levels were recorded. Data on duration of smoking habit (pack-years) and family history of smoking were collected. Information on daily toothbrushing and flossing and most recent visit to a dentist/dental hygienist was gathered. Clinical and radiographic periodontal examination was performed and unstimulated whole salivary flow rate (UWSFR) was determined. OYC was assessed using the oral rinse sampling method. Power analysis was done, and group comparisons were performed. Logistic regression analysis was performed and P values <5% reflected statistical significance. Respectively, 23, 24, 22, and 23 individuals with comparable mean ages were included in groups 1, 2, 3, and 4. In groups 1 and 2, participants had a smoking history of (mean ± SD) 24.7 ± 3.2 and 10.6 ± 2.5 pack-years. Plaque index, clinical attachment loss, and probing depth were higher in groups 1 (P < .05), 2 (P < .05), and 3 (P < .05) than in group 4. Number of missing teeth was significantly higher in group 1 compared with groups 2 (P < .05), 3 (P < .05), and 4 (P < .05). There was no difference in UWSFR amongst the groups. OYC was greater in group 1 than in groups 2 (P < .05), 3 (P < .05), and 4 (P < .05). OYC was greater in groups 2 (P < .05) and 3 (P < .05) than in group 4. In prediabetic cigarette smokers, OYC appears to be influenced by hyperglycaemia, whilst in nondiabetic smokers, the severity of periodontal inflammation appears to be the determining factor in OYC.

Exploring the diversityof uncommon oral yeast species andassociated risk factorsamong substance abusers insouthwestern Iran.

Yeast species are a group of coexistent microorganisms in the oral cavity that can cause opportunistic infections in vulnerable individuals, including addicts. This study aimed to identify the yeast species profile responsible for oral yeast colonization (OYC) and the associated risk factors in patients with substance use disorder (SUD) in Ahvaz, Iran. Oral samples were collected from drug users hospitalized in 12 addiction treatment centers, and the related clinical information was mined. Oral yeast species were identified using 21-plex PCR and sequencing of the internal transcribed spacer region (ITS1-5.8S-ITS2). A total of 244 yeast strains were identified from 245 individuals with substance abuse. Candida albicans was the most common species (37.7%) and non-albicans Candida was responsible for 57.7% of OYC, primarily C. dubliniensis (33.2%) and C. glabrata (11.9%). Moreover, uncommon oral yeasts constituted 5.3% of species, including Saccharomyces cerevisiae, Clavispora lusitaniae, Pichia kluyveri, Geotrichum candidum, Magnusiomyces capitatus, Hanseniospora opuntiae, Wickerhamomyces subpelliculosus, Trichosporon asahii, and Aureobasidium pullulans. Importantly, OYC exhibited associations with such factors as duration of drug use, daily drug consumption rate, opioid utilization, oral drug administration, and the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) score. The present study is the pioneering investigation revealing the prevalence and diversity of oral yeast species, along with associated risk factors, in individuals with SUD in southwestern Iran. Furthermore, it underscores the importance of developing efficient and cost-effective diagnostic methods tailored for resource-constrained settings.

In vitro comparison of antifungal activity of conventional alcohol sprays and antimicrobial photodynamic therapy on acrylic denture resin.

Traditionally, alcohol sprays are used for disinfection of acrylic-base denture surfaces. A limited number of studies have assessed the role of antimicrobial photodynamic therapy (aPDT) in this regard; however, it remains debatable whether conventional alcohol sprays are superior to aPDT in terms of antifungal activity or vis versa. The aim of the present in vitro study is to compare the antifungal activity of conventional alcohol sprays and aPDT on acrylic denture resin. Individuals wearing complete dentures at least on one arch were included. Dentures were randomly divided into three groups. Groups 1-3 were disinfected with an alcohol-based antiseptic spray and aPDT, respectively. Assessment of oral yeast growth was done using swab samples. The culture mediums were incubated at 37∘C for 72 hours and viewed through a microscope. The numbers of colony forming units (CFU/ml) were determined. P< 0.05 were considered statistically significant. At baseline, the mean CFU/ml in Groups 1-3 were comparable. After disinfection, a statistically significant reduction in microbial CFU/ml was observed in Groups 1 (P< 0.05) and 2 (P< 0.05) compared with baseline. In Group 3, there was no difference in CFU/ml throughout the study. After disinfection, there was no difference in microbial CFU/ml in dentures in Groups 1 and 2. Conventional alcohol sprays are as effective as aPDT towards reducing oral yeasts CFU/ml on acrylic denture resin.

Risk factors for malignant oral mucosal lesion development (literature review). Part 1. Endogenous and biological factors

Relevance. Oral mucosal cancer (OMC) is the sixteenth most common cancer worldwide. The high mortality rate is mainly due to the asymptomatic course of the disease in the early stages and late detection when the tumour process poorly responds to treatment. Determining the impact of various risk factors and establishing their relationship are necessary to prevent and diagnose malignant oral mucosal lesions in the early stages.Purpose. Based on the modern literature, the study aimed to determine the impact value of various internal and external risk factors on malignant oral mucosal lesion development and assess the risk factors’ relationship.Material and methods. The research material included the analysis of literature from databases – Elsevier, PubMed, Elibrary, Google Academy, Medline and Cyberleninka. The study included literature sources in Russian and English.Results. Based on modern literature, we have determined endogenous and biological risk factors for malignant oral mucosal lesion development. The study noted the high role of microbiome changes and the presence of dysbiosis in patients with malignant neoplasms and proved the direct involvement of Candida fungi in carcinogenesis. The development of oral mucosal cancer and the presence and severity of oral yeast colonization and human papillomavirus infection showed a positive correlation. Chronic oral diseases, which are susceptible to malignant transformation or contribute to the development of carcinomas, have been identified, and their relationship has been established with biological risk factors, age, sex of the patient and duration of the disease course.Conclusion. The studies considered in this part of the review prove the influence of endogenous and biological factors on the development of malignant neoplasms of the oral cavity and determine their relationship. However, many mechanisms remain unexplored to date. Effective primary and secondary prevention implementation needs improvement and the development of a multidisciplinary approach to research methodology, study the complex impact of all groups of risk factors on the development of malignant oral mucosal lesions.

18-25 Yaş Arası Bireylerden İzole Edilen Mayaların Biyofilm Oluşturma Kapasitesinin ve Antifungal Direncinin İn Vitro Olarak Değerlendirilmesi

Microbiota studies are an increasingly important issue today. In the literature, there are limited studies on the antifungal resistance and biofilm formation capacity of yeasts isolated from the mouths of young individuals. For this reason, our study was carried out with 133 yeast isolates isolated from the mouths of 17 young individuals between the ages of 18-25 in 2018-2020. When the biofilm-forming capacities of 133 isolates were examined, it was determined that 99.25% were biofilm producers by tissue culture plate method and 66.92% by tube method. One hundred thirty-three yeast isolates and seven reference strains were first evaluated against fluconazole antifungal by agar disc diffusion method. The isolates were found to be susceptible to fluconazole. According to this result, 20 isolates with strong biofilm-forming capacity were selected from 133 yeast isolates. Antifungal resistance was evaluated with fluconazole, itraconazole, clotrimazole, amphotericin B and nystatin gradient test strips. It was determined that 20 isolates were resistant to amphotericin B, and 18 were resistant to nystatin antifungal. It was determined that the sensitivity of itraconazole to 14 isolates and clotrimazole to 3 isolates was dose-dependent. As a result, azole group antifungals can be used mainly in treating oral yeast infections.

Recombinant hemagglutinin displaying on yeast reshapes congenital lymphocyte subsets to prompt optimized systemic immune protection against avian influenza infection.

Prophylactic vaccination is regarded as the most effective means to control avian flu infection. Currently, there is a need for a universal vaccine that provides broad and long-lasting protection against influenza virus. Meanwhile, although yeast-based vaccines have been used in clinic, studies are still required to further understand the molecular mechanism of yeast-based vaccines under physiological conditions. We generated a yeast-based vaccine against influenza hemagglutinin (HA) of H5, H7 and H9 using surface displaying technology and evaluated the protective efficacy of chickens after exposure to H9N2 influenza virus. Oral yeast vaccine provided less clinical syndrome, reduced viral loading and alleviated airway damage significantly. Compared to the commercial inactivated vaccine, yeast vaccine stimulated the activation of splenic NK and APCs cells and boosted TLR7-IRF7-IFN signaling in spleen. Meanwhile, γδ T cells in the bursa of Fabricius were activated and the innate lymphoid cells (ILCs) in the bursa of Fabricius promoted the CILPs to differentiate to ILC3 cells in oral yeast birds. Moreover, the reshaped gut microbiota and a suppressed Th17-IL17-mediated inflammation in intestine was observed in oral yeast chickens, which might facilitate the recovery of intestinal mucosal immunity upon virus infection. Collectively, our findings suggest that oral yeast based multivalent bird flu vaccines provide an attractive strategy to update host defense function via reshapes of multi-systemic immune homeostasis.

Antifungal Susceptibility of Oral Candida Isolates from Mother-Infant Dyads to Nystatin, Fluconazole, and Caspofungin.

The carriage of Candida albicans in children's oral cavities is associated with a higher risk for early childhood caries, so controlling this fungus in early life is essential for preventing caries. In a prospective cohort of 41 mothers and their children from 0 to 2 years of age, this study addressed four main objectives: (1) Evaluate in vitro the antifungal agent susceptibility of oral Candida isolates from the mother-child cohort; (2) compare Candida susceptibility between isolates from the mothers and children; (3) assess longitudinal changes in the susceptibility of the isolates collected between 0 and 2 years; and (4) detect mutations in C. albicans antifungal resistance genes. Susceptibility to antifungal medications was tested by in vitro broth microdilution and expressed as the minimal inhibitory concentration (MIC). C. albicans clinical isolates were sequenced by whole genome sequencing, and the genes related to antifungal resistance, ERG3, ERG11, CDR1, CDR2, MDR1, and FKS1, were assessed. Four Candida spp. (n = 126) were isolated: C. albicans, C. parapsilosis, C. dubliniensis, and C. lusitaniae. Caspofungin was the most active drug for oral Candida, followed by fluconazole and nystatin. Two missense mutations in the CDR2 gene were shared among C. albicans isolates resistant to nystatin. Most of the children's C. albicans isolates had MIC values similar to those from their mothers, and 70% remained stable on antifungal medications from 0 to 2 years. For caspofungin, 29% of the children's isolates showed an increase in MIC values from 0 to 2 years. Results of the longitudinal cohort indicated that clinically used oral nystatin was ineffective in reducing the carriage of C. albicans in children; novel antifungal regimens in infants are needed for better oral yeast control.

Candida species and oral mycobiota of patients clinically diagnosed with oral thrush.

Overgrowth of Candida yeasts in the oral cavity may result in the development of oral thrush in immunocompromised individuals. This study analyzed the diversity and richness of the oral mycobiota of patients clinically diagnosed with oral thrush (OT), follow-up of oral thrush patients after antifungal therapy (AT), and healthy controls (HC). Oral rinse and oral swab samples were collected from 38 OT patients, 21 AT patients, and 41 healthy individuals (HC). Pellet from the oral rinse and oral swab were used for the isolation of oral Candida yeasts on Brilliance Candida Agar followed by molecular speciation. ITS1 amplicon sequencing using Illumina MiSeq was performed on DNA extracted from the oral rinse pellet of 16 OT, 7 AT, and 7 HC oral rinse samples. Trimmed sequence data were taxonomically grouped and analyzed using the CLC Microbial Genomics Module workflow. Candida yeasts were isolated at significantly higher rates from oral rinse and swab samples of OT (68.4%, p < 0.001) and AT (61.9%, p = 0.012) patients, as compared to HC (26.8%). Predominance of Candida albicans specifically, was noted in OT (60.5%, p < 0.001) and AT (42.9%, p = 0.006) vs. HC (9.8%), while non-albicans Candida species was dominant in HC. Analysis of oral mycobiota from OT patients showed the presence of 8 phyla, 222 genera, and 309 fungal species. Low alpha diversity (Shannon index, p = 0.006; Chao-1 biased corrected index, p = 0.01), varied beta diversity (Bray-Curtis, p = 0.01986; Jaccard, p = 0.02766; Weighted UniFrac, p = 0.00528), and increased relative abundance of C. albicans (p = 3.18E-02) was significantly associated with the oral mycobiota of OT vs. HC. This study supported that C. albicans is the main etiological agent in oral thrush and highlights the association of fungal biodiversity with the pathophysiology of oral thrush.

The Antimicrobial Potential of Vanillin-Incorporated Irreversible Hydrocolloid Impression Material

The hydrocolloid impression material is one of the most important materials extensively used in several procedures in the dental field. It is mainly applied for diagnostic and planning in the rehabilitation of oral, orthodontic, and maxillofacial prostheses due to its biocompatibility with the oral tissues, low toxicity, ease of use, and relatively low cost. When doing the impression, the material might be contaminated with blood, saliva, and biofilm from within the patient’s mouth. In these procedures, there are high chance that the microorganisms can be transmitted from patients to the casting materials and then to the dentists or to the dental lab technicians. Several types of disinfectants have been introduced for use to disinfect dental impressions. This study aims to investigate the antimicrobial potential of vanillin-incorporated irreversible hydrocolloid impression material on Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, and Candida albicans. The hydrocolloid impression material used in this study is Alginate, Kromopan class A type I, Lascod, Italy. Different concentrations of vanillin (0.1%, 0.5%, and 1% w/w) were added to the impression powder, and the impression samples were made by mixing the alginate powder with water and pouring them on sterile plastic plates. Staphylococcus aureus ATCC 5638, Klebsiella pneumoniae (clinical isolate), Escherichia coli ATCC 11775, and Candida albicans ATCC 10231 were prepared to 105 CFU/ml suspensions in sterile normal saline solution. A total of 100 μL of each microbial suspension was evenly spread onto the surface of the impression and left for 1 min. Then, a 2 x 2 cm2 sterile Whatman filter paper was placed on the impression sample surface to make an imprint and transferred to the Brain Heart Infusion (BHI) agar plate. The number of colonies growing on the BHI agar was counted after incubation at 37°C for 24-48 h. Impression material without vanillin was used as a control. It was found that adding vanillin to the materials could significantly inhibit all tested microorganisms, and the inhibitory efficiency ranged from 12% to 98%. K. pneumoniae showed the most resistance since the inhibitory effect started at 0.5% w/w vanillin and the maximum suppression was 84% at 1% w/w vanillin. On the other hand, S. aureus appeared to be the most sensitive species, as the suppressive response started at 0.1% w/w vanillin and the percentage of inhibition was as high as 98% at 1% w/w vanillin. In conclusion, we combined different concentrations of vanillin (0.1%, 0.5%, and 1% w/w) into the impression material and it showed a significant antimicrobial potential against all tested oral bacteria and yeasts (S. aureus, K. pneumoniae, E. coli, and C. albicans). The suppressive effects were dose-dependent and ranged from 12% to 98%. This did not only disinfect the impression material from the inside but also disinfected the impression from the time it was inserted into the patient’s mouth. Using this hydrocolloid impression material incorporated with vanillin could be beneficial to eliminate cross-infection for dental personnel. Nonetheless, further studies are necessary to investigate some physical properties of this impression material, such as setting time, tensile strength, elastic recovery, and detailed reproduction.

The potential impact of delivery mode and breastfeeding on oral Candida species carriage in a population of young adults.

In early life, children are exposed to microorganisms from maternal and environmental sources, which influence the development of their microbiome throughout life. Several studies have demonstrated the influence of the delivery mode and breastfeeding on the oral microbiome of children, mostly regarding bacterial colonization. However, their influence on the oral fungal carriage is still underexplored. This study aimed to assess the association of the delivery and feeding mode with the oral carriage of yeasts in adulthood. Fungal oral carriage was evaluated by collecting unstimulated saliva in 185 healthy dental students (mean age of 21.51±1.55 years old; 81.6% females). Yeast identification was performed by culture in ChromAgar Candida medium and sequencing of the 18S genes and ITS regions for determination of the species. Demographic and clinical data of each participant was recorded through questionnaires and oral examinations were performed in a subgroup of participants (n=49). Candida species were isolated in 37.5% of all participants. The prevalence of yeasts in the oral cavity was significantly higher in those who were born by vaginal delivery compared to those born by caesarean-section (p=0.035), whereas no statistically significant differences were observed regarding breastfeeding (p=0.398). Low salivary flow rate and frequency of dental visits also were associated with oral yeast carriage (p<0.05). Our study suggests a possible impact of the type of delivery on fungal colonization, which is sustained throughout life due to oral health-related factors.

Oral Yeast Load and Species of Young Individuals Aged 18-25

Oral Yeast Load and Species of Young Individuals Aged 18-25

Adhesion of Yeast and Bacteria to Oral Surfaces.

Colonization of surfaces in the human body by microorganisms is an early, essential, step in the initiation of infectious disease. We have developed in vitro assays to investigate interactions between yeast or bacterial cells and human tissues, fluids, or prostheses. Such assays can be used to identify the adhesins, ligands, and receptors involved in these interactions, for example, by determining which components of the microbe or human tissue/fluid interfere with adherence in the assay. The assays can also be applied to find ways of preventing adhesion, and subsequent disease, by investigating the effects of different conditions and added compounds on adherence in the in vitro assays. Here we describe assays for measuring adhesion of the oral yeast Candida albicans, a common commensal and opportunistic pathogen, or the bacterium Staphylococcus epidermidis, which is not normally pathogenic but is known to form biofilms on medical prostheses. The assays described belong to two approaches to investigating adhesion and biofilm formation: (i) retention at a fixed time point following liquid washes, and (ii) retention against a continuous flow of medium.

P350 Oropharyngeal candidiasis in HIV infected patients: associated risk factors and antifungal susceptibility testing of candida species by disc diffusion method

Poster session 3, September 23, 2022, 12:30 PM - 1:30 PM ObjectivesTo isolate and identify Candida species by the standard microbiological method.To estimate the frequency of oral Candidiasis according to age, sex, and other factors [CD4 + count, ART, tobacco consumption, diabetes, upper respiratory tract infection (URTI), recent antibiotic consumption] in HIV-positive patients.To determine the Antifungal Susceptibility pattern of the Candida species by Disc Diffusion Method.MethodologyA hospital-based cross-sectional study was conducted for 6 months in the Department of Microbiology of Sukraraj Tropical and Infectious Disease Hospital, Kathmandu, Teku, Nepal. A total of 408 HIV-positive patients attending the ART center of the hospital of different age and sex were included in the study. Study variables like CD4 + count, tobacco consumption, diabetes, URTI, and recent antibiotic consumption were noted.Standard microbiological guidelines were followed for the oral swab collection and transportation. Specimen was seeded on SDA agar plates (SDA with chloramphenicol and cycloheximide). Preliminary identification of the Candida was done on the basis of colony characteristics, gram staining, and germ tube test. Further for the speciation of Candida species, HiCrome™ Candida Differential Agar (HImedia, India) was applied where on the basis of coloration and colony morphology speciation was done. Similarly, Cornmeal Agar (Dalmau plate culture technique) and sugar Fermentation test were applied to confirm the Candida species.Muller-Hinton agar supplemented with 2% glucose and 0.5 μg/ml methylene blue dye (GMB) medium was used to perform the antifungal susceptibility testing of Candida isolates. Antifungal susceptibility testing (AST) of isolates was performed and interpreted according to Clinical and Laboratory Standards Institute (CLSI) M44-A document. Candida albicans ATCC 90028 was taken as the reference strain. All the data were entered in Microsoft excel and Chi-square was used to find out the association between the frequency of oral candidiasis and study variables.ResultsAmong 408 studied subjects, 225 (55.1%) were males and 183 (44.9%) were females. Of the participants, 116 (28.4%) had regular tobacco smoking habit, diabetes 10 (2.5%), URTIs 30 (7.4%), antibiotic consumption 44 (10.8%) and ART use 394 (96.6%). The CD4 + cell count of respondents ranged from 12 - 2425 cells/mm³. Candida albicans 53 (81.5%) was the most frequently encountered species followed by C. tropicalis 3 (4.6%), C. krusei 2 (3.1%), C. glabrata 1 (1.5%) and 6 (9.2%) other Candida species. A total of 26 patients had CD4+ ≤200 cells/mm3 and 39 patients had CD4+ >200 cells/mm3. There was no significant association in the occurrence of oral candidiasis among males and females (P = .966), tobacco consumption (P = .051), ART use (P = .188), diabetes (P = .722). Whereas, there was a significant association between oral Candida carriage and CD4 + cell count ≤ 200 cells/mm3 (P <.001), URTI (P = .029), and recent antibiotic consumption (P = .002). Amphotericin B was the most potent antifungal followed by voriconazole, itraconazole, and conversely fluconazole the most resistant.Conclusion Candida albicans was the common species isolated in our study. Candida Chrome Agar can be used as a routine media for rapid identification and Candida speciation. AST needs to be done routinely to know the susceptibility pattern of isolates and initiate proper treatment of patients. Since oral yeast colonization was associated with low CD4 + count (<200 cells/mm3). Thus, oral lesions can serve as early markers for HIV infection.

Impacts of Menstruation, Community Type, and an Oral Yeast Probiotic on the Vaginal Microbiome.

ABSTRACTA healthy state of the vaginal microbiome can prevent vaginal disease and promote successful fertilization and healthy pregnancies. Little is known about the stability of the vaginal microbiome and the influence of factors such as diet and probiotics. While less explored, yeast probiotics have an interesting potential because of their immunomodulatory and pathogen inhibition capacities. In this study, we investigated the impact of the oral yeast probiotic Saccharomyces cerevisiae CNCM I-3856 on the vaginal microbiomes of 52 healthy women using 16S and internal transcribed spacer (ITS) amplicon sequencing and quantitative PCR (qPCR). The vaginal fungal loads remained low, even after oral yeast supplementation, complicating the analysis of the vaginal mycobiome. Lactobacillus crispatus and Lactobacillus iners were the most dominant species in our study population and were found to codominate in 23% of the baseline samples. Bifidobacterium, Streptococcus, and Prevotella were also frequently found. The microbiome profiles were dynamic: 69% of women showed a shift in the dominant community members at least once during the 42-day sampling period. In addition, lower Lactobacillus abundances were observed at the time points after menstruation. Higher relative abundances of Lactobacillus with more L. iners-dominated samples and a trend toward lower relative abundances of Prevotella were observed in the probiotic group, but analyses of the effects of the yeast probiotic were complicated by differences already present at the onset of the study. Thus, our findings especially highlighted that the impact of menstruation and the stratification of women based on the dominant vaginal taxa before randomization and inclusion is important for future research: while the impact of the yeast probiotic on vaginal microbiome in healthy women was limited.IMPORTANCE How to define and promote a healthy state of the vaginal microbiome is not well understood. Knowledge of which underlying factors shape the microbial community composition of the vagina and how to modulate them will contribute to vaginal disease prevention and improve fertility. Here, we found that taking the menstrual cycle into account when designing a microbiome study is highly recommended: menstruation also showed to be poses an interesting time point for intervention because of the drop in the abundance of L. crispatus. Furthermore, the early stratification of groups (e.g., placebo versus treatment) according to the dominant taxa can be of high added value since menstruation impacts vaginal taxa differently, i.e., L. iners remains stable, in contrast to L. crispatus.

Immunomodulatory effect and safety of TNF-α RNAi mediated by oral yeast microcapsules in rheumatoid arthritis therapy.

Rheumatoid arthritis (RA) is a chronic autoimmune disease that requires long-term treatment and monitoring. Inhibition of inflammatory gene expression by gene therapy is a significant breakthrough in RA treatment, but the lack of a safe and effective gene delivery system hinders its application. Since oral administration can significantly reduce wound infection caused by parenteral administration, it also has the advantages of high patient compliance and convenience. Therefore, oral administration may be the best option for the treatment of this chronic disease. In this study, we developed a novel oral drug system by delivering tumor necrosis factor-α (TNF-α) short hairpin RNA (shRNA) mediated by non-pathogenic yeast to evaluate its regulation of systemic immune inflammation and safety in RA. Non-pathogenic yeast can resist the destruction of the gastrointestinal acid-base environment and can be recognized by the intestinal macrophages and act on systemic inflammatory lesions. Oral administration of yeast-mediated TNF-α shRNA significantly reduced the expression of TNF-α predominant pro-inflammatory factors in intestinal macrophages and joint synovium, and up-regulated the expression of anti-inflammatory cytokine IL-10 and M2 macrophages, systematically regulating the inflammatory response. This yeast-mediated oral gene delivery system can not only significantly inhibit knee joint synovial inflammation, but also has no toxic effects on peripheral blood and major organs. Therefore, yeast-mediated oral delivery of TNF-α shRNA may be used as a novel gene therapy strategy to treat RA through immunomodulating the mononuclear phagocyte system from the intestine to the joint synovium, and ultimately regulating systemic and local immune inflammation, providing new ideas for the clinical treatment of RA.

Gut mucosal immune responses and protective efficacy of oral yeast Cyprinid herpesvirus 2 (CyHV-2) vaccine in Carassius auratus gibelio

Cyprinid herpesvirus 2 (CyHV-2) causes herpesviral hematopoietic necrosis (HVHN) disease outbreaks in farmed Cyprinid fish, which leads to serious economic losses worldwide. Although oral vaccination is considered the most suitable strategy for preventing infectious diseases in farmed fish, so far there is no commercial oral vaccine available for controlling HVNN in gibel carp (C. auratus gibelio). In the present study, we developed for the first time an oral vaccine against CyHV-2 by using yeast cell surface display technology and then investigated the effect of this vaccine in gibel carp. Furthermore, the protective efficacy was evaluated by comparing the immune response of a single vaccination with that of a booster vaccination (booster-vaccinated once 2 weeks after the initial vaccination). Critically, the activities of immune-related enzymes and genes expression in vaccine group, especially in the booster vaccine group, were higher than those in the control group. Moreover, strong innate and adaptive immune responses could be elicited in both mucosal and systemic tissues after receipt of the oral yeast vaccine. To further understand the protective efficacy of this vaccine in gibel carp, we successfully developed the challenge model with CyHV-2. Our results showed the relative percent survival was 66.7% in the booster vaccine group, indicating this oral yeast vaccine is a promising vaccine for controlling CyHV-2 disease in gibel carp aquaculture.

Abstract 5218: Oral beta-glucan enhanced anti-ganglioside antibody titer after vaccination against high-risk neuroblastoma: Results of a randomized trial

Abstract Background and Aim: Ganglioside GD2/GD3 vaccine stimulated robust antibody response among patients with high-risk metastatic neuroblastoma (HR-NB) who had prior disease progression (J Clin Oncol 39:215-226, 2020). High anti-GD2-IgG1antibody titer was associated with improved progression-free survival and overall survival in multivariable analyses. A gel formulation of yeast beta-glucan was used as an oral vaccine adjuvant, but its importance remained unproven. Patients and Methods: In a follow-up randomized Phase II trial (Clinicaltrials.gov identifier: NCT00911560), seven vaccine injections at 1, 2, 3, 8, 20, 32 and 52 weeks were administered to patients with HR-NB during their first or subsequent remissions. Each subcutaneous vaccine injection consisted of 30 ug each of GD2 and GD3, which was lactonized and conjugated to keyhole limpet hemocyanin and mixed with the subcutaneous saponin OPT-821 adjuvant at 150 µg/m2. No patients in this analysis received prior ganglioside vaccine. They were randomized to Arm 1 (n=54) receiving no glucan, or Arm 2 (n=53) receiving oral beta-glucan regimen (40 mg/kg/day, 14 days on/14 days off) starting at week 1. From week 6 onwards, all 107 patients received oral beta-glucan regimen through year end or up to disease progression. Serum IgG1 against GD2 and GD3, and IgM against GD2 were measured by ELISA at (right before) each vaccine injection. Wilcoxon rank sum test was used to compare antibody titers between the 2 arms. Results: In both arms, patients had comparable disease status at study entry, with 70% each in first remission. The remaining patients were in second remission after one prior disease progression. Consistently higher antibody response was observed among Arm 2 patients. The primary endpoint was met for anti-GD2-IgG1 titer at vaccine injection #6 at 32 weeks (p=0.08). Per protocol design, statistical significance (p&amp;lt;0.1) of anti-GD2-IgG1titer was observed at vaccine #5 (2.7-fold), #6 (1.4-fold), and #7 (4.1-fold), irrespective of being in first or second remission at study entry. Total anti-GD2-IgG1 antibody exposure (AUC) up to vaccine #7 for Arm 2 was 1.9-fold higher than that of Arm 1 (p=0.05). In contrast, anti-GD2-IgM achieved statistical significance only at vaccine #4 (p=0.001), and for anti-GD3-IgG1, only at vaccine #5 (p=0.07). Oral beta-glucan was well tolerated, and no patient showed pain or neuropathic side effects despite having higher antibody titers. Conclusion: Adding oral yeast beta-glucan as vaccine adjuvant during the first 6 weeks of immunization significantly enhanced the anti-GD2-IgG1 antibody response without added toxicities. Its impact on patient survival will require a longer clinical follow-up. Citation Format: Irene Y. Cheung, Audrey Mauguen, Yi Feng, Govind Ragupathi, Ellen Basu, Stephen S. Roberts, Shakeel Modak, Brian H. Kushner, Nai-Kong V. Cheung. Oral beta-glucan enhanced anti-ganglioside antibody titer after vaccination against high-risk neuroblastoma: Results of a randomized trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5218.

Denture Base PMMA Resin Containing Vanillin Inhibits Biofilm Formation of Bacteria Associated with Malodor

Dentures are prosthetic device made of polymethyl methacrylate acrylic (PMMA) resin generally used by elderly people to replace their real teeth. However, the porosity and surface irregularities of acrylic resin are undesirable aspects of the denture base that can support colonization of oral microorganisms on the denture surface, particularly those associated with malodor. Oral malodor is a common and upsetting situation frequently found in denture wearers due to inadequate denture cleaning. A large number of strategies had been employed to minimize the potential bacterial pathogens, including mechanical brushing and using chemical agents. Therefore, we have developed denture PMMA resin containing vanillin and evaluated antimicrobial potential against four species of bacteria related to oral malodor. Denture base resin samples were prepared with dimensions of 10 mm x 10 mm x 1 mm. according to the amount of incorporating vanillin concentrations (0.1%, 0.5% and 1.0% w/w) and coated with saliva. Then, the biofilm formation of four species of bacteria (Porphyromonas gingivalis ATCC 33277, Aggregatibacter actinomycetemcomitans ATCC 33384, Fusobacterium nucleatum ATCC 25586, and Actinomyces viscosus ATCC 19246) was performed on resin samples in anaerobically condition for 48-72 h. Denture resin sample without vanillin was prepared in the same way and used as a control. The quantity of vital biofilm was assessed by WST Microbial Cell Counting Kit (Dojindo Molecular Technologies, USA). Kruskal-Wallis test followed by Dunn’s method were applied for statistical analysis. The results showed that in the groups of 0.5% and 1.0% w/w vanillin, significant decreases of biofilm mass were observed in all tested bacteria (P. gingivalis, A. actinomycetemcomitans, and F. nucleatum) compared with controls, except for A. viscosus. Approximately 30% to 38% bacterial biofilm reduction was demonstrated at 1.0% w/w vanillin on three species of bacteria, whereas 7% to 27% biofilm decreases were observed at 0.5% vanillin. No significant biofilm reduction was observed in A. viscosus. This conforms to our previous studies which revealed the antimicrobial properties of denture PMMA resin containing vanillin on respiratory pathogens and oral yeast. Denture base resin consisting of vanillin may be considered as a promising dental appliance for the use to prevent or solve the problem of oral malodor in patients who wear dentures.

Raman Spectroscopy of Oral Candida Species: Molecular-Scale Analyses, Chemometrics, and Barcode Identification.

Oral candidiasis, a common opportunistic infection of the oral cavity, is mainly caused by the following four Candida species (in decreasing incidence rate): Candida albicans, Candida glabrata, Candida tropicalis, and Candida krusei. This study offers in-depth Raman spectroscopy analyses of these species and proposes procedures for an accurate and rapid identification of oral yeast species. We first obtained average spectra for different Candida species and systematically analyzed them in order to decode structural differences among species at the molecular scale. Then, we searched for a statistical validation through a chemometric method based on principal component analysis (PCA). This method was found only partially capable to mechanistically distinguish among Candida species. We thus proposed a new Raman barcoding approach based on an algorithm that converts spectrally deconvoluted Raman sub-bands into barcodes. Barcode-assisted Raman analyses could enable on-site identification in nearly real-time, thus implementing preventive oral control, enabling prompt selection of the most effective drug, and increasing the probability to interrupt disease transmission.