Lactobacillus johnsonii is a dominant Lactobacillus in the murine oral mucosa and has chitinase activity that compromises fungal cell wall integrity.

The oral microbiome is a critical determinant of health and disease, as interactions between oral microorganisms can influence their physiology and the development or severity of oral infections. Lactobacilli have a widely recognized antagonistic relationship with Candida albicans and may exhibit probiotic properties that limit oral fungal infection. We previously reported that Lactobacillus johnsonii strain MT4, an oral strain isolated from C57BL/6 mice, can induce global changes in the murine oral microbiome and has anti-Candida activity in vitro. To build on this information, we analyzed its abundance on the mouse oral mucosa, tested its impact on the severity and progression of oropharyngeal candidiasis (OPC) in a mouse model, and further explored the mechanism of antifungal activity in vitro. Our findings reveal that L. johnsonii MT4 is a dominant cultivable Lactobacillus in the oral mucosa of C57BL/6 mice. Strain MT4 has chitinase activity against C. albicans, which damages the cell wall and compromises fungal metabolic activity. Oral inoculation with strain MT4 causes a reduction in the Candida-induced rise in the abundance of oral enterococci and oral mucosal damage. This research underscores the potential of L. johnsonii strain MT4 as a novel probiotic agent in the prevention or management of OPC, and it contributes to a better understanding of the role of oral bacterial microbiota role in the pathogenesis of fungal infections. IMPORTANCE: The interactions between the opportunistic pathogen Candida albicans and resident oral bacteria are particularly crucial in maintaining oral health. Emerging antifungal drug-resistant strains, slow-paced drug discovery, and the risk of side effects can compromise the effectiveness of current treatments available for oropharyngeal candidiasis. This study advances the search for alternative microbiome-targeted therapies in oral fungal infections. We report that Lactobacillus johnsonii strain MT4 prevents the Candida-induced bloom of dysbiotic oral enterococci and reduces oral mucosal lesions in an oropharyngeal candidiasis murine model. We also show that this strain directly compromises the cell wall and reduces fungal metabolic activity, partly due to its chitinase activity.

Clinical aPDT's effect on Candida albicans: Antifungal susceptibility, virulence gene expression, and correlation with leukocyte and neutrophil counts.

BACKGROUND: Our previous clinical trial demonstrated that antimicrobial photodynamic therapy (aPDT) with methylene blue (MB) and potassium iodide (KI) effectively killed Candida albicans (C. albicans) in adult AIDS patients with oral candidiasis, regardless of biofilm formation or 25S rDNA genotype. This study evaluated changes in antifungal susceptibility and virulence gene expression in C. albicans before and after aPDT, and explored factors related to clinical aPDT efficacy. METHODS: Twenty-one adult AIDS patients with C. albicans oral candidiasis were divided into Group a (400 µM MB, N = 11) and Group b (600 µM MB, N = 10). Both groups received two aPDT treatments, where MB was applied for 5 min, followed by 300 mM KI, and illuminated for 30 min (37.29 J/cm²). C. albicans isolates were collected before and after treatment to assess antifungal susceptibility (fluconazole, itraconazole, flucytosine, amphotericin B) and gene expression (CAT1, HWP1). Peripheral blood tests were analyzed for correlations with aPDT efficacy. RESULTS: aPDT reduced minimum inhibitory concentration (MIC) values for amphotericin B, fluconazole, and flucytosine, with significant reductions primarily after the first treatment. MIC reductions differed between groups, with Group a showing greater decreases in flucytosine and fluconazole MICs, and Group b in amphotericin B MICs. No significant changes in CAT1 or HWP1 expression were observed. Clinical efficacy of aPDT negatively correlated with leukocyte and neutrophil levels. CONCLUSIONS: aPDT effectively reduces MICs of antifungal drugs against C. albicans isolated from treated patients, particularly after the first treatment. The concentration of MB required to reduce MICs varies among different antifungal drugs. aPDT does not alter CAT1 or HWP1 expression, and its clinical efficacy in eradicating C. albicans is negatively associated with leukocyte and neutrophil levels.

A novel mucoadhesive film containing probiotic extract for oral candidiasis treatment: Formulation and antifungal evaluation.

Probiotic strains offer a novel and potentially effective approach to treat oral candidiasis. Buccal mucoadhesive films have attracted considerable attention in recent years due to their unique ability to adhere and persist on the oral mucosa, while gradually releasing their encapsulated drug content. Therefore, the aim of the study was to develop mucoadhesive films containing probiotic extract for treatment of oral candidiasis. Mucoadhesive films were fabricated with hydrophilic polymers, such as polyvinyl alcohol (PVA) and hydroxy propyl methyl cellulose (HPMC). Then, films were evaluated regarding their thickness, pH, tensile strength and elongation, swelling, in vitro release and antifungal activity. The type of polymer used had an impact on the mechanical properties, swelling and release of the films. Films prepared using PVA showed significantly higher tensile strength and elongation at break values compared to those prepared using HPMC. However, swelling index increased with enhancing HPMC concentration in the films. The release of probiotic extract from the film prepared with HPMC occurred slowly. Based on these results, films containing 54 % HPMC and 26 % PVA were selected as optimal formulation. Moreover, it was found that optimal film containing probiotic extract could inhibit the growth of Candida albicans. Regarding to the obtained results, probiotic oral adhesive mucoadhesive films can be considered as a promising alternative to traditional methods in the treatment of candidiasis.

Characteristics of Candida albicans Derived From HIV-Positive Individuals With Oral Candidiasis: Genotyping, Phenotypic Variation, Antifungal Susceptibility, and Biofilm Formation.

BACKGROUND: Oral candidiasis (OC) is one of the most common mucosal infections in those afflicted with HIV/AIDS. This study aimed to provide detailed information on the phenotype, genotype, antifungal susceptibility, and biofilm formation ability of oral Candida albicans isolated from HIV-infected patients with OC. METHODS: A total of 25 C. albicans isolates were collected from oral lesions of HIV-infected patients referred to Behavioral Diseases Counseling Center affiliated with Ahvaz Jundishapur University of Medical Sciences, Iran. The antifungal susceptibility testing was done according to CLSI M27 guideline (fourth edition). The crystal violet method was used to evaluate the biofilm formation ability of isolates. Different phenotypes were identified on yeast extract-peptone-dextrose agar medium supplemented with phloxine B. Genotyping analysis of the isolates was performed using high-resolution melting (HRM) assays and ABC genotyping. RESULTS: The highest and lowest susceptibility of the C. albicans isolates was found for fluconazole 24 (96%) and ITC 18 (72%), respectively. Forty-eight percent of the isolates had high biofilm formation ability and exhibited gray cell type. The most common genotype was genotype B (52%). HRM analysis of HIS3, EF3, and CDC3 markers showed three, four, and five different groups, respectively. CONCLUSION: Investigating the phenotype, antifungal susceptibility and biofilm formation ability of the C. albicans isolates obtained from oral lesions of HIV-infected patients revealed that the dominant genotypes in the current research could cause more serious infections from the oral source. We recommend further research with a larger sample size to determine the molecular epidemiology of C. albicans among HIV patients in Iran.

Genotyping of oral Candida albicans and Candida tropicalis strains in patients with orofacial clefts undergoing surgical rehabilitation by MALDI-TOF MS: Case-series study.

Patients with orofacial clefts are more likely to develop oral fungal diseases due to anatomo-physiological changes and surgical rehabilitation treatment. This case-series study evaluated the genetic diversity and dynamics of oral colonization and spread of C. albicans and C. tropicalis in four patients with orofacial clefts, from the time of hospital admission, perioperative and outpatient follow-up, with specialized physician. Candida biotypes previously identified by CHROMagar Candida and PCR methods were studied by MALDI-TOF MS assays and clustering analyses. Possible correlations with pathogenicity characteristics were observed, including production of hydrolytic exoenzymes and the antifungal sensitivity profiles. Amphotericin B-sensitive and fluconazole-resistant (low frequency) C. tropicalis and C. albicans, including clinically compatible MIC of nystatin, were found in the oral cavity of these patients. Clusters of isolates revealed phenomena of (i) elimination in the operative phase, (ii) maintenance or (iii) acquisition of oral C. tropicalis in the perioperative period and specialized outpatient and medical follow-up. For C. albicans, these phenomena included (i) elimination in the operative phase, (ii) acquisition in the operative phase and propagation from the hospital environment, and (iii) maintenance during hospitalization and operative phase. Amphotericin B and nystatin were shown to be effective in cases of clinical treatment and/or prophylaxis, especially considering the pre-existence of fluconazole-resistant strains. This study confirmed the phenomena of septic maintenance, septic neocolonization and septic elimination involving the opportunistic pathogens. MALDI-TOF MS associated with clustering analysis may assist the monitoring of clinical isolates or groups of epidemiologically important microbial strains in the hospital setting.

Mechanisms of action of Lactobacillus spp. in the treatment of oral candidiasis.

Candida albicans is often associated with oral candidiasis, and drug-resistance profiles have contributed to an increase in morbidity and mortality. It is known that Lactobacillus spp. acts by competing for adhesion to the epithelium, absorption of nutrients and modulation of the human microbiota. Therefore, they are important to assist in the host's microbiological balance and reduce the growth of Candida spp. Until now, there have been no reports in the literature of reviews correlating to the use of Lactobacillus spp. in the treatment of oral candidiasis. Thus, this review aims to highlight the mechanisms of action of Lactobacillus spp. and methods that can be used in the treatment of oral candidiasis. This is a study carried out through the databases PubMed Central and Scientific Electronic Library Online, using the following keywords: Oral Candidiasis and Lactobacillus. Original articles about oral candidiasis were included, with both in vitro and in vivo analyses, and published from 2012 to 2022. Lactobacillus rhamnosus was the most common microorganism used in the experiments against Candida, acting mainly in the reduction of biofilm, filamentation, and competing for adhesion sites of Candida spp. Among in vivo studies, most researchers used immunosuppressed mouse modelsof Candida infection. The studies showed that Lactobacillus has a great potential as a probiotic, acting mainly in the prevention and treatment of mucosal diseases. Thus, the use of Lactobacillus may be a good strategy for the treatment of oral candidiasis.

Early Candida colonisation impact on patients and healthcare professionals in an intensive care unit.

OBJECTIVES: Candida spp. is an opportunistic pathogen that causes superficial and invasive infections with nosocomial outbreaks without strict hygiene protocols. Herein, we assessed oral colonisation by Candida spp. in 209 Intensive Care Unit (ICU) patients between July 2021 and April 2022, conducting clinical, epidemiological, and microbiological characterisation of those developing oral or invasive candidiasis. METHODS: Initial oral swabs were collected within 24 h of admission in the ICU, followed by collections on Days 2, 4, 6 and 8. Swabs from denture-wearing patients, abiotic surfaces, healthcare professionals' hands, and retroauricular regions were also obtained. Recovered yeasts and filamentous fungi were identified using MALDI-TOF MS and morphological characteristics, respectively. Genetic similarity of Candida spp. isolates was evaluated using Amplified fragment length polymorphism (AFLP), and the antifungal susceptibility profile was determined by broth microdilution. RESULTS: In the study, 64.11% of patients were orally colonised by Candida spp. Of these, 80.59% were colonised within the first 24 h. Oral colonisation also occurred on subsequent days: 50%/Day 2, 26.92%/Day 4, and 11.53%/Days 6 and 8. Of the patients, 8.61% had oral candidiasis, mainly pseudomembranous. Among orally colonised patients, 2.23% developed invasive candidiasis. Besides, 89.47% of healthcare professionals evaluated were colonised. MALDI-TOF MS identified different yeast species, and C. albicans (45.34%), C. tropicalis (15.7%), and C. parapsilosis sensu stricto (9.88%) were the most prevalent. AFLP analysis indicated a high genetic correlation (≥97%) between C. parapsilosis sensu stricto isolates from patients and professionals. Three resistant C. albicans isolates were also found. CONCLUSION: This study reported a diversity of yeast and filamentous fungi species in ICU patients and highlighted early Candida spp. colonisation risks for invasive candidiasis, as well as the potential horizontal transmission in the nosocomial setting, emphasising the need for effective infection control measures.

An approach to analyze spatiotemporal patterns of gene expression at single-cell resolution in Candida albicans-infected mouse tongues.

Microbial gene expression measurements derived from infected organs are invaluable to understand pathogenesis. However, current methods are limited to "bulk" analyses that neglect microbial cell heterogeneity and the lesion's spatial architecture. Here, we report the use of hybridization chain reaction RNA fluorescence in situ hybridization (HCR RNA-FISH) to visualize and quantify Candida albicans transcripts at single-cell resolution in tongues of infected mice. The method is compatible with fixed-frozen and formalin-fixed paraffin-embedded tissues. We document cell-to-cell variation and intriguing spatiotemporal expression patterns for C. albicans mRNAs that encode products implicated in oral candidiasis. The approach provides a spatial dimension to gene expression analyses of host-Candida interactions. IMPORTANCE: Candida albicans is a fungal pathobiont inhabiting multiple mucosal surfaces of the human body. Immunosuppression, antibiotic-induced microbial dysbiosis, or implanted medical devices can impair mucosal integrity enabling C. albicans to overgrow and disseminate, causing either mucosal diseases such as oropharyngeal candidiasis or life-threatening systemic infections. Profiling fungal genes that are expressed in the infected mucosa or in any other infected organ is paramount to understand pathogenesis. Ideally, these transcript profiling measurements should reveal the expression of any gene at the single-cell level. The resolution typically achieved with current approaches, however, limits most gene expression measurements to cell population averages. The approach described in this report provides a means to dissect fungal gene expression in infected tissues at single-cell resolution.

Efficacy of Curcumin-Mediated Antimicrobial Photodynamic Therapy on Candida spp.-A Systematic Review.

Oral candidiasis is a common problem among immunocompetent patients. The frequent resistance of Candida strains to popular antimycotics makes it necessary to look for alternative methods of treatment. The authors conducted a systematic review following the PRISMA 2020 guidelines. The objective of this review was to determine if curcumin-mediated blue light could be considered as an alternative treatment for oral candidiasis. PubMed, Google Scholar, and Cochrane Library databases were searched using a combination of the following keywords: (Candida OR candidiasis oral OR candidiasis oral OR denture stomatitis) AND (curcumin OR photodynamic therapy OR apt OR photodynamic antimicrobial chemotherapy OR PACT OR photodynamic inactivation OR PDI). The review included in vitro laboratory studies with Candida spp., in vivo animal studies, and randomized control trials (RCTs) involving patients with oral candidiasis or prosthetic stomatitis, published only in English. The method of elimination of Candida species in the studies was curcumin-mediated aPDT. A total of 757 studies were identified. Following the analysis of the titles and abstracts of the studies, only 42 studies were selected for in-depth screening, after which 26 were included in this study. All studies evaluated the antifungal efficacy of curcumin-mediated aPDT against C. albicans and non-albicans Candida. In studies conducted with planktonic cells solutions, seven studies demonstrated complete elimination of Candida spp. cells. The remaining studies demonstrated only partial elimination. In all cases, experiments on single-species yeast biofilms demonstrated partial, statistically significant inhibition of cell growth and reduction in biofilm mass. In vivo, curcumin-mediated aPDT has shown good antifungal activity against oral candidiasis also in an animal model. However, its clinical efficacy as a potent therapeutic strategy for oral candidiasis requires few further RCTs.

Combinatorial actions of IL-22 and IL-17 drive optimal immunity to oral candidiasis through SPRRs.

Oropharyngeal candidiasis (OPC) is the most common human fungal infection, arising typically from T cell immune impairments. IL-17 and IL-22 contribute individually to OPC responses, but here we demonstrate that the combined actions of both cytokines are essential for resistance to OPC. Mice lacking IL-17RA and IL-22RA1 exhibited high fungal loads in esophagus- and intestinal tract, severe weight loss, and symptoms of colitis. Ultimately, mice succumbed to infection. Dual loss of IL-17RA and IL-22RA impaired expression of small proline rich proteins (SPRRs), a class of antimicrobial effectors not previously linked to fungal immunity. Sprr2a1 exhibited direct candidacidal activity in vitro, and Sprr1-3a-/- mice were susceptible to OPC. Thus, cooperative actions of Type 17 cytokines mediate oral mucosal anti-Candida defenses and reveal a role for SPRRs.

Chitosan from the base of Flammulina velutipes stipe alleviates oral Candida albicans infection via modulating Th-17 cell differentiation and Streptococcus mutans.

The base of Flammulina velutipes (F. velutipes) stipe are agricultural wastes generated during the cultivation of edible fungus F. velutipes with high amount of chitin. Herein, this study firstly prepared chitosan from the base of F. velutipes stipe (FVC) and its structure was identified. It was confirmed that FVC acted as an antigenic substance to activate the immune system in vivo and in vitro, drive T cells to differentiate into Th-17 cells, and establish an effective mucosal immune barrier in the oral cavity, thus inhibited C. albicans infection; On the other hand, FVC maintained the oral flora stability and significantly reduced the abundance of Streptococcus spp., which was closely related to C. albicans infection. On this basis, the inhibitory effects of FVC on oral pathogens Streptococcus mutans and Lactobacillus casei associated with C. albicans infection were further verified, and it was demonstrated that FVC effectively interfered with the growth of pathogenic bacteria by inducing the production of intracellular ROS to damage bacterial cells. Therefore, FVC may be potentially exploited as a novel approach to the prevention and treatment of oral C. albicans infection.

Clinical and mycological analysis of colonization by Candida spp. in oral leukoplakia and oral lichen planus.

OBJECTIVE: This study aims to analyze the prevalence of Candida spp. colonization in oral leukoplakia and oral lichen planus lesions, verify the influence of systemic and local factors, besides identify and determine the in vitro antifungal susceptibility profile of Candida species. MATERIALS AND METHODS: Samples were collected by swabbing from oral lesions and healthy mucosa and cultured on Sabouraud Dextrose and CHROMagar® Candida plates. Species identification was confirmed with MALDI-TOF MS analysis. RESULTS: Candida spp. was found in 36.8% of cases of oral leukoplakia and 18.2% of cases of oral lichen planus. Candida albicans was the only species found in oral lichen planus lesions (n = 2, 100%) and the most prevalent in oral leukoplakia (n = 5, 76.4%). Among the non-albicans Candida species found in oral leukoplakia were C. parapsilosis (n = 2, 25.5%) and C. tropicalis (n = 1, 14.1%). Candida isolates were susceptible to all antifungals tested. CONCLUSION: C. albicans was the most commonly found species in the studied lesions. No correlation was found between systemic and local factors with positive cases of oral lichen planus. However, smoking and alcohol consumption may be associated with positive cases of oral leukoplakia, especially the non-homogeneous clinical form. In addition, there is a possible predisposition to associated Candida colonization in cases of epithelial dysplasia found in oral leukoplakia. The antifungal medications tested showed excellent efficacy against isolates.

Candida species in periodontitis: A new villain or a new target?

OBJECTIVES: Recent research indicated that fungi might have a role in periodontitis alongside traditional periodontal pathogens. This state-of-the-art narrative review explores current concepts on the involvement of Candida species in periodontitis, and suggests the potential for ecological management of this disease. DATA, SOURCES AND STUDY SELECTION: A literature search was conducted for a narrative review on Web of Science, PubMed, Medline and Scopus about periodontitis associated with Candida species. Published articles, including case reports, case series, observational and interventional clinical trials, and critical appraisals of the literature were retrieved and reviewed. CONCLUSIONS: Several factors predispose individuals to periodontitis associated with Candida species. These include systemic diseases that lead to immunosuppression and oral environment changes such as cigarette smoking. While a consistent significant increase in the detection rate of Candida species in patients with periodontitis has not been universally observed, there is evidence linking Candida species to the severity of periodontitis and their potential to worsen the condition. Candida species may participate in the development of periodontitis in various ways, including cross-kingdom interactions with periodontal pathogens, changes in the local or systemic environment favoring the virulence of Candida species, and interactions between Candida-bacteria and host immunity. CLINICAL SIGNIFICANCE: Mechanical plaque control is the most common treatment for periodontitis, but its effectiveness may be limited, particularly when dealing with systemic risk factors. Understanding the specific role of Candida in periodontitis illuminates innovative approaches for managing the ecological balance in periodontal health.

Oral candidiasis in liver transplant patients: species identification and antifungal susceptibility profile.

OBJECTIVE: This study aimed to verify oral candidiasis, identify the causative species, and investigate the antifungal susceptibility of yeasts isolated from liver transplant patients. METHODS: A descriptive analysis of 97 patients who underwent liver transplantation was conducted at a hospital. Two clinical examinations (Collections A and B) of the oral cavity were performed. Oral material was collected from all patients, inoculated in Sabouraud Dextrose Agar, and incubated at 35℃ for 48 hours. Samples were identified by molecular sequencing of the internal trascribed space region of rDNA. RESULTS: An antifungal susceptibility test with fluconazole, amphotericin B, and micafungin was performed using the Clinical and Laboratory Standards Institute yeast broth microdilution method. Among the patients, 15 presented with oral candidiasis: eight in Collection A and seven in Collection B. The primary type of candidiasis was atrophic, followed by pseudomembranous candidiasis. The most prevalent species was Candida albicans (nine), followed by Candida glabrata (three), Candida tropicalis (two), and Candida dubliniensis (one). Regarding susceptibility to fluconazole, of the 15 samples, 11 were susceptible, three were susceptible in a dose-dependent manner, and one was resistant. CONCLUSION: The most commonly identified type of candidiasis was atrophic, with C. albicans and C. glabrata being the most prevalent causative species. One fluconazole-resistant isolate each of C. tropicalis and C. albicans were identified.

IMPROVEMENT OF THE METHODOLOGY OF BIOMATERIAL COLLECTION FOR THE DIAGNOSIS OF THE ORAL CAVITY MUCOSA DISEASES.

Aim - to improve the methodology for collecting material from lesions of the oral mucosa for exfoliative cytological examination. A group of patients diagnosed with B37.0 Candida stomatitis was examined. To clarify the diagnosis, various methods of collecting biological material from the tongue of patients were used, namely, the method using a cytobrush with subsequent fixation of cytological material on a slide. The microbiota of the back of the tongue was analyzed in 12 patients with glossitis and 12 healthy subjects (the control group). The microscopic method of research was used - using an immersion microscope MICROmed@XS-3330, and the morphological and tinctorial properties of microorganisms were determined. In ten fields of view, the number of leukocytes, the nature of epithelial cells, and the presence of various microorganisms were detected and counted. A comparison of the quality of the use of the microscope method for the study of the tongue microbiota of patients with candidal glossitis was performed under the conditions of taking pathological material using a dental scalpel and an oral cytobrush. For a reasonable interpretation of the results and determination of their significance, a statistical analysis was performed to determine the frequency of detection of microorganisms in patients with glossitis and healthy subjects, depending on the nature of the material taken from the back of the tongue using a dental scalpel or cytobrush. The studies showed that the etiologic structure of glossitis pathogens was dominated by Candida yeast-like fungi, but cases of leptotrichosis aetiology were observed (16.7%). Monococci and gram-negative monobacteria were detected in all studied groups. An increase in the diversity of microorganisms was found when the material was taken with a cytobrush. The microbiota of all subjects differed depending on the type of instrument used for sampling. Thus, in the group of healthy individuals, the interdental brush helped to detect twice as many streptococci as a scalpel. In patients with candidiasis, a brush biopsy showed a 2.7-fold increase in gram-positive diplococci, twice as many streptococci and gram-positive bacilli, three times as many staphylococci, 2.25 times as many clusterforming gram-negative cocci, and 2.3 times as many gram-negative diplococci. A significant increase in the diversity of microorganisms was observed with the cytobrush compared to the use of a dental scalpel. In patients with glossitis, the accumulation of keratinized epithelial cells was significantly higher compared to the presence of young cells in healthy subjects, regardless of the method of sampling.

Lactoferrin as a potential therapeutic for the treatment of Candida-associated denture stomatitis.

BACKGROUND: The use of prostheses in the oral cavity creates favorable conditions for Candida colonization, which may subsequently lead to Candida-associated denture stomatitis (CADS). Due to its many contributing factors and frequent relapses, CADS is difficult to manage. Given the rise in drug resistance among fungal species, it is critical to develop new therapeutic approaches, reduce the required dosage of medications, and minimize the toxicity and side effects of therapy. HIGHLIGHT: Salivary lactoferrin, a multifunctional glycoprotein, is thought to be the first line of defense against microbial invasion of mucosal surfaces. CONCLUSION: Current research emphasizes the capability of lactoferrin and its derivatives to eliminate a broad spectrum of Candida species. It may be an appealing option for use in monotherapy or in combination with common medications for oral stomatitis treatment. This review provides an overview of the current understanding of lactoferrin's anti-fungal effects in oral candidiasis.

Oral Candida albicans strain diversity and maintenance in HIV positive women in South Africa.

OBJECTIVE: This study investigated C. albicans strain diversity and maintenance in the oral cavity of HIV positive women over a 6 month period. STUDY DESIGN: C. albicans strains were isolated from 17 HIV positive women at Charlotte Maxeke Academic Hospital, Johannesburg at 3 intervals over a 6 month period. Strains were genotyped using ABC and Multilocus Sequence Typing (MLST) techniques. In the MLST technique, for each strain, a Diploid Sequence Type (DST) number was obtained. Using cluster analysis, an Unweighted Pair Group Method with Arithmetic Mean (UPGMA) dendrogram and a matrix of strain similarities were generated. Strains were also compared to the previous South African isolates documented in the MLST database. RESULTS: Ninety four percent of women carried the same ABC genotype for 6 months. MLST technique, showed that ten women (58.8%) carried the same DST at 2 visits, while seven (41.2%) carried different DST at all visits. Further analysis showed that 64.7% of women were recolonised with different strains and 35.3% carried the same strains of C. albicans with heterozygosity. A total of 40 diploid sequence types were identified of which 27 DSTs were unique to this study group that were added to the MLST database. Most of the strains were closely related to previously isolated strains from South Africa. CONCLUSION: Recolonization of the oral cavity with different strains and microevolution of the original strains of C. albicans can occur, which can be a potential problem for HIV patients, in whom highly virulent and drug resistant strains can emerge.

Effectiveness of a tissue conditioner containing antifungals in a rat model of denture stomatitis.

AIM: This study investigated the effectiveness of a drug-modified tissue conditioner in an animal model of denture stomatitis. METHODS AND RESULTS: Wistar rats wore a Candida albicans-contaminated palatal device for 4 days. Next, nystatin (Nys) or chlorhexidine (Chx) were added to a tissue conditioner in their raw or ß-cyclodextrin-complexed (ßCD) forms at their minimum inhibitory concentrations. As controls, one group was not subjected to any procedure (NC), one group used sterile devices, one group had denture stomatitis but was not treated (DS), and another had the devices relined with the tissue conditioner without the addition of any drug (Soft). After 4 days of treatment, treatment effectiveness was assessed visually, histologically, and through CFU count, and myeloperoxidase (MPO) and N-acetylglucosaminidase (NAG) assays. Rats from the Soft, Nys, Nys:ßCD, and Chx groups presented a significant decrease in the microbial load compared with the untreated group. Treatment groups showed lower MPO and NAG activity compared to the non-treated group. CONCLUSIONS: The addition of antifungals to a soft tissue conditioner can be a promising approach for denture stomatitis treatment.

Impact of Brief Exposure to Lysozyme and Lactoferrin on Pathogenic Attributes of Oral Candida.

INTRODUCTION AND AIMS: Adhesion to buccal epithelial cells (BEC) and denture acrylic surfaces (DAS), germ tube (GT) formation, cell surface hydrophobicity (CSH), and haemolysin production are attributes associated with pathogenicity of Candida. Candida albicans and Candida dubliniensis are allied in causing oral candidosis. Lysozyme and lactoferrin exert antimicrobial activity on a range of oral microorganisms, including Candida. There is no information on the impact of brief exposure to lysozyme and lactoferrin on adhesion-related attributes and haemolysin production of aforementioned oral Candida isolates. Thus, we investigated the impact of lysozyme and lactoferrin on adhesion to BEC and DAS, GT formation, CSH, and haemolysin production of these isolates. METHODS: After exposure to lysozyme and lactoferrin for 1 hour, susceptibility to lysozyme and lactoferrin of 20 isolates each of C albicans and C dubliniensis isolates was determined following a 48-hour period of incubation. Candida cell suspensions, obtained from colony-forming units after this period, were assessed for adhesion to BEC and DAS, GT formation, CSH, and haemolysin production using in vitro assays. RESULTS: Exposure to lysozyme and lactoferrin significantly suppressed the ability of C albicans and C dubliniensis isolates to adhere to BEC and DAS, GT formation, CSH, and haemolysin production (P < 0.01 for all virulent attributes tested). CONCLUSIONS: These data provide a tantalising glimpse into the possibility that exposure to either lysozyme or lactoferrin, even for a brief period, would induce a sustainable antifungal effect by suppressing adhesion-related attributes and haemolysin production of these oral Candida species in vitro. Resistance to conventional antifungal agents has been reported in clinical isolates of Candida. The presence of such resistance indicates the need for possible alternative therapies to facilitate the management of oral candidosis. Further research on the pharmacodynamics of lysozyme and lactoferrin and their effects on candidal pathogenic attributes should be fostered, with the vision of developing novel topical antifungal drugs.

Drug-resistant oral candidiasis in patients with HIV infection: a systematic review and meta-analysis.

BACKGROUND: Oral candidiasis (OC) is a prevalent opportunistic infection in patients with human immunodeficiency virus (HIV) infection. The increasing resistance to antifungal agents in HIV-positive individuals suffering from OC raised concerns. Thus, this study aimed to investigate the prevalence of drug-resistant OC in HIV-positive patients. METHODS: Pubmed, Web of Science, Scopus, and Embase databases were systematically searched for eligible articles up to November 30, 2023. Studies reporting resistance to antifungal agents in Candida species isolated from HIV-positive patients with OC were included. Baseline characteristics, clinical features, isolated Candida species, and antifungal resistance were independently extracted by two reviewers. The pooled prevalence with a 95% confidence interval (CI) was calculated using the random effect model or fixed effect model. RESULTS: Out of the 1942 records, 25 studies consisting of 2564 Candida species entered the meta-analysis. The pooled prevalence of resistance to the antifungal agents was as follows: ketoconazole (25.5%, 95% CI: 15.1-35.8%), fluconazole (24.8%, 95% CI: 17.4-32.1%), 5-Flucytosine (22.9%, 95% CI: -13.7-59.6%), itraconazole (20.0%, 95% CI: 10.0-26.0%), voriconazole (20.0%, 95% CI: 1.9-38.0%), miconazole (15.0%, 95% CI: 5.1-26.0%), clotrimazole (13.4%, 95% CI: 2.3-24.5%), nystatin (4.9%, 95% CI: -0.05-10.3%), amphotericin B (2.9%, 95% CI: 0.5-5.3%), and caspofungin (0.1%, 95% CI: -0.3-0.6%). Furthermore, there were high heterogeneities among almost all included studies regarding the resistance to different antifungal agents (I2 > 50.00%, P < 0.01), except for caspofungin (I2 = 0.00%, P = 0.65). CONCLUSIONS: Our research revealed that a significant number of Candida species found in HIV-positive patients with OC were resistant to azoles and 5-fluocytosine. However, most of the isolates were susceptible to nystatin, amphotericin B, and caspofungin. This suggests that initial treatments for OC, such as azoles, may not be effective. In such cases, healthcare providers may need to consider prescribing alternative treatments like polyenes and caspofungin. REGISTRATION: The study protocol was registered in the International Prospective Register of Systematic Reviews as PROSPERO (Number: CRD42024497963).