Point prevalence, microbiology and antifungal susceptibility patterns of oral Candida isolates colonizing or infecting Mexican HIV/AIDS patients and healthy persons

Analysis of subgingival bacterial and fungal diversity in patients with peri-implantitis based on 16sRNA and internal transcribed spacer sequencing

Aim: To analyze subgingival fungal diversity in peri-implant inflammation patients and their relationship with bacteria. Methods: We collected saliva samples from four groups. 16sRNA and internal transcribed spacer sequencing was performed preceded by quantitative PCR and enzyme-linked immunosorbent assay tests. Analyses were done using R and Cytoscape software. Results: Significant differences were observed in the Abundance-based Coverage Estimator (ACE) index between control and peri-implantitis samples. Basidiomycota was the dominant fungal species, while Firmicutes dominated the bacteria. The most abundant fungal and bacterial species were 's_unclassified g Apiotrichum' and 's_unclassified g Streptococcus', respectively. Dothiorella was strongly associated with immunoglobulin G levels, with positive correlations between specific microorganisms and peri-implantitis in Q-PCR. Conclusion: Our findings have significant clinical implications, suggesting specific fungal and bacterial taxa roles in peri-implant inflammation.

Functional Characterization of a Bacillus-Derived Novel Broad-Spectrum Antifungal Lipopeptide Variant against Candida tropicalis and Candida auris and Unravelling Its Mode of Action

Limited treatment options, recalcitrance, and resistance to existing therapeutics encourage the discovery of novel antifungal leads for alternative therapeutics. Antifungal lipopeptides have emerged as potential candidates for developing new and alternative antifungal therapies. In our previous studies, we isolated and identified the lipopeptide variant AF4 and purified it to homogeneity via chromatography from the cell-free supernatant of Bacillus subtilis. AF4 was found to have broad-spectrum antifungal activity against more than 110 fungal isolates. In this study, we found that clinical isolates of Candida tropicalis and Candida auris exposed to AF4 exhibited low MICs of 4 to 8 mg/L. Time-kill assays indicated the in vitro pharmacodynamic potential of AF4. Biocompatibility assays demonstrated ~75% cell viability at 8 mg/L of AF4, indicating the lipopeptide's minimally cytotoxic nature. In lipopeptide-treated C. tropicalis and C. auris cells, scanning electron microscopy revealed damage to the cell surface, while confocal microscopy with acridine orange(AO)/propidium iodide (PI) and FUN-1 indicated permeabilization of the cell membrane, and DNA damage upon DAPI (4',6-diamidino-2-phenylindole) staining. These observations were corroborated using flow cytometry (FC) in which propidium iodide, 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA), and rhodamine 123 (Rh123) staining of cells treated with AF4 revealed loss of membrane integrity, increased reactive oxygen species (ROS) production, and mitochondrial membrane dysfunction, respectively. Membrane perturbation was also observed in the 1,6-diphenyl-1,3,5-hexatriene (DPH) fluorescence study and the interaction with ergosterol was observed by an ergosterol binding assay. Decreased membrane dipole potential also indicated the probable binding of lipopeptide to the cell membrane. Collectively, these findings describe the mode of action of AF4 against fungal isolates by membrane disruption and ROS generation, demonstrating its antifungal potency. IMPORTANCE C. tropicalis is a major concern for candidiasis in India and C. auris has emerged as a resistant yeast causing difficult-to-treat infections. Currently, amphotericin B (AMB) and 5-flucytosine (5-FC) are the main therapeutics for systemic fungal infections; however, the nephrotoxicity of AMB and resistance to 5-FC is a serious concern. Antifungal lead molecules with low adverse effects are the need of the hour. In this study, we briefly describe the antifungal potential of the AF4 lipopeptide and its mode of action using microscopy, flow cytometry, and fluorescence-based assays. Our investigation reveals the basic mode of action of the investigated lipopeptide. This lipopeptide with broad-spectrum antifungal potency is apparently membrane-active, and there is a smaller chance that organisms exposed to such a compound will develop drug resistance. It could potentially act as a lead molecule for the development of an alternative antifungal agent to combat candidiasis.

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

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

Epidemiology and Prevalence of Oral Candidiasis in HIV Patients From Chad in the Post-HAART Era

Oral candidiasis remains a common problem in HIV-infected individuals, especially in sub-Saharan Africa. Here, we performed the first study in Chad on the prevalence of oral yeasts carriage and oral candidiasis in HIV-positive subjects from southern Chad and analyzed the influence of HAART, CD4⁺ T-cell numbers, and antimycotics in 589 patients. These patients were recruited from a specialized medical center for HIV patients in Sarh and from a rural medical health dispensary in the vicinity, including a total of 384 HIV-positive and 205 HIV-negative individuals. Yeasts obtained from oral specimen were identified by MALDI-TOF MS and their antifungal susceptibility profiles determined. The overall prevalence of yeast colonization and symptomatic oral candidiasis in HIV-infected patients was 25.1%. The prevalence of oral candidiasis was higher in untreated than in HAART-treated HIV-positive patients (16% vs. 2%; p < 0.01). Oral candidiasis was furthermore associated with high fungal burdens of Candida albicans and a CD4⁺ T-cell number <200/μl. A shift toward non-albicans Candida species was observed under nucleoside-based HAART therapy. Azole antifungal drug resistance was only observed for the intrinsically resistant species Candida krusei and Candida glabrata. Prevalence of oral candidiasis in the studied area was very low. The species distribution was similar to other countries around the world, with C. albicans being dominant. Candida dubliniensis was not isolated. Nucleoside-based HAART therapy significantly reduced oral colonization as well as occurrence of oral candidiasis caused by C. albicans and led to a species shift toward non-albicans species. Antifungal resistance was not yet a concern in Chad.

Oral candidiasis in human immunodeficiency virus-infected patients under highly active antiretroviral therapy

Human immunodeficiency virus has plagued mankind since the 1980's when the first case was documented. Human immunodeficiency virus-induced immunocompromised state can lead to several systemic and local manifestations, which often culminates in mortality. Oral candidiasis was one of the most prevalent opportunistic infections noted in human immunodeficiency virus-infected patients. The advent of highly active antiretroviral therapy has led to a significant reduction in both the mortality and the morbidity of infected patients. The combined antiretroviral therapy has also led to a decrease in the incidence of opportunistic infections including oral candidiasis. Thus, the presence of well-established oral candidiasis in human immunodeficiency virus-infected patients under highly active antiretroviral therapy could be considered as an indicator of potential treatment failure. The present manuscript aims to review the published literature assessing the effect of highly active antiretroviral therapy on the incidence of oral candidiasis in human immunodeficiency virus-infected patients.

The Prevalence, Etiological Agents, Clinical Features, Treatment, and Diagnosis of HIV-Associated Oral Candidiasis in Pediatrics Across the World: A Systematic Review and Meta-Analysis

In HIV-infected pediatrics, oral candidiasis (OC) is a global issue of concern due to its association with dysphagia, malnutrition, and mortality. The present systematic review and meta-analysis are the first to determine the prevalence of OC in HIV-infected pediatrics worldwide. We searched international (PubMed, Web of Science, Scopus, and Embase) databases for studies published between January 2000 to May 2020 reporting the epidemiologic features of OC in HIV-infected pediatrics. Inclusion and exclusion criteria were defined to select eligible studies. Data were extracted and presented according to PRISMA guidelines. The results of the meta-analysis were visualized as a forest plot. Heterogeneity was also analyzed using the I ², and τ² statistics. The publication bias was evaluated using Egger test. The literature search revealed 1926 studies, of which 34 studies met the eligibility criteria, consisting of 4,474 HIV-infected pediatrics from 12 different countries. The overall prevalence of OC among HIV-infected pediatrics was 23.9% (95% CI 17.3-32.0%), and Candida albicans was the most prevalent etiologic agent. Pseudomembranous candidiasis was the predominant clinical manifestation in HIV-infected pediatrics suffering from OC. Thirty articles involving 4,051 individuals provided data on HIV treatment status. Among the 4,051 individuals, 468 (11.53%) did not receive HIV treatment. The data from 11 articles demonstrated that HIV treatment was significantly associated with a reduction in oral Candida colonization or infection. In contrast, others showed the opposite relationship or did not report any statistical data. A high level of I ² (I ² = 96%, P < 0.01) and τ² (τ² = 1.36, P < 0.01) was obtained among studies, which provides evidence of notable heterogeneity between studies. OC is approximately frequent in HIV-positive children. Therefore, efforts should be made to teach dental and non-dental clinicians who care for HIV-infected pediatrics to diagnose and treat this infection.

Antifungal Resistance of Candida Species Isolated from HIV Patients in a Tertiary Care Hospital, Mysuru, Karnataka

Context:

Candidiasis still remains as a common opportunistic infection in patients with human immunodeficiency virus (HIV). Drug resistance has become a serious health concern because of indiscriminate usage and dosage.

Aim:

To determine the antifungal resistance pattern of Candida albicans and non-albicans Candida (NAC) from HIV patients.

Subjects and Methods:

The study was carried out in the department of microbiology at a tertiary care hospital. Candida isolates obtained from HIV patients were tested for drug susceptibility by Vitek-2 automated system.

Results:

Antifungal susceptibility pattern (n=109) revealed that 15% of the isolates were resistant to at-least one and 85% were sensitive to all the drugs tested. About 10% and 19% of C. albicans showed resistance to fluconazole and flucytosine respectively. Among non-albicans tested, only C. tropicalis (14%) exhibited resistance to flucytosine.

Conclusions:

Knowledge on epidemiology, species prevalence, and drug resistance pattern may guide for effective therapy. This reduces morbidity and also improves the quality of life.

How the evolving epidemics of opioid misuse and HIV infection may be changing the risk of oral sexually transmitted infection risk through microbiome modulation

The epidemiology of sexually transmitted infections (STI) is constantly evolving, and the mechanisms of infection risk in the oral cavity (OC) are poorly characterized. Evidence indicates that microbial community (microbiota) compositions vary widely between the OC, genitalia and the intestinal and rectal mucosa, and microbiome-associated STI susceptibility may also similarly vary. The opioid misuse epidemic is at an epidemic scale, with >11 million US residents misusing in the past 30 days. Opioids can substantially influence HIV progression, microbiota composition and immune function, and these three factors are all mutually influential via direct and indirect pathways. While many of these pathways have been explored independently, the supporting data are mostly derived from studies of gut and vaginal microbiotas and non-STI infectious agents. Our purpose is to describe what is known about the combination of these pathways, how they may influence microbiome composition, and how resultant oral STI susceptibility may change. A better understanding of how opioid misuse influences oral microbiomes and STI risk may inform better mechanisms for oral STI screening and intervention. Further, the principles of interaction described may well be applied to other aspects of disease risk of other health conditions which may be impacted by the opioid epidemic.

Oral candidal carriage correlates with CD4+ cell count but not with HIV and highly active antiretroviral therapy status

AIM

The occurrence of oropharyngeal candidiasis (OPC) may be influenced by oral candidal carriage (OCC). Although OPC is strongly associated with low CD4⁺ cell count (400-700 cells/mm³ ) and a lack of highly active antiretroviral therapy (HAART), the effect of these two parameters on OCC is debatable. We investigated the oral candidal carriage, species diversity, antifungal susceptibility and the association of OCC with CD4⁺ cell count and HAART.

METHODS

Oral candidal isolates from 120 HIV⁺ patients (60 receiving and 60 not receiving HAART) and 60 healthy controls were quantified, and their species determined using standard culture and biochemical methods, followed by antifungal susceptibility testing using the agar dilution method.

RESULTS

The OCC was significantly higher in HIV⁺ patients; Candida albicans was the most frequently isolated species in both groups, followed by Candida tropicalis. Candidal density carriage correlated significantly with CD4⁺ cell count, but not with HIV and HAART status. Among the isolates from HIV⁺ patients, 35.4% showed reduced susceptibility to fluconazole.

CONCLUSION

HIV status results in significantly elevated rates of OCC C albicans remains the predominant pathogen, although other species are emerging rapidly. Resistance to fluconazole is on the rise, and more efficient treatment strategies need to be implemented.

Therapeutic tools for oral candidiasis: Current and new antifungal drugs

BACKGROUND

Candidiasis is one of the most common opportunistic oral infections that presents different acute and chronic clinical presentations with diverse diagnostic and therapeutic approaches. The present study carries out a bibliographic review on the therapeutic tools available against oral candidiasis and their usefulness in each clinical situation.

MATERIAL AND METHODS

Recent studies on treatment of oral candidiasis were retrieved from PubMed and Cochrane Library.

RESULTS

Nystatin and miconazole are the most commonly used topical antifungal drugs. Both antifungal drugs are very effective but need a long time of use to eradicate the infection. The pharmacological presentations of miconazole are more comfortable for patients but this drug may interact with other drugs and this fact should be assessed before use. Other topical alternatives for oral candidiasis, such as amphotericin B or clotrimazole, are not available in many countries. Oral fluconazole is effective in treating oral candidiasis that does not respond to topical treatment. Other systemic treatment alternatives, oral or intravenous, less used are itraconazole, voriconazole or posaconazole. Available novelties include echinocandins (anidulafungin, caspofungin) and isavuconazole. Echinocandins can only be used intravenously. Isavuconazole is available for oral and intravenous use. Other hopeful alternatives are new drugs, such as ibrexafungerp, or the use of antibodies, cytokines and antimicrobial peptides.

CONCLUSIONS

Nystatin, miconazole, and fluconazole are very effective for treating oral candidiasis. There are systemic alternatives for treating recalcitrant infections, such as the new triazoles, echinocandins, or lipidic presentations of amphotericin B.

Subgingival areas as potential reservoirs of different Candida spp in type 2 diabetes patients and healthy subjects

OBJECTIVES

The aim of this cross-sectional observational study was to compare the prevalence of different oral Candida spp. in patients with Type 2 Diabetes and chronic periodontitis in two oral sites: dorsal surface of the tongue and subgingival area. In order to determine subgingival areas as potential reservoirs of yeasts, this study aimed to find differences in the yeasts' detection between the dorsum of the tongue, as the oral site most commonly inhabited with microorganisms, and subgingival samples. Additionally, potential predictors for the yeasts prevalence were determined.

MATERIAL AND METHODS

Subjects (N = 146) were divided into four groups: group A- healthy individuals without periodontitis, group B- healthy individuals with chronic periodontitis, group C- Type 2 Diabetes patients with good glycoregulation and Chronic periodontitis and group D- Type 2 Diabetes patients with poor glycoregulation and Chronic periodontitis. Samples were obtained from the tongue by swabbing. Subgingival plaque samples were taken by paper points and periodontal curette. Isolation and identification of different Candida spp. was done using ChromAgar medium. In addition, germ-tube production and carbohydrate assimilation tests were performed.

RESULTS

The prevalence of Candida spp. was higher in diabetics with poor glycoregulation. The most frequently isolated species was Candida albicans followed by Candida glabrata and Candida tropicalis. In 15.6% of cases, Candida spp. was present in the subgingival area while absent on the tongue. Multivariate regression model showed that HbA1c was Candida spp. predictor for both locations.

CONCLUSIONS

Our results confirmed that there are Candida spp. carriers among subjects with clinically healthy oral mucosa. Also, this study identified subgingival areas as potential reservoirs of these pathogenic species. Glycoregulation has been recognized as a positive predictor factor of Candida spp.

Candida species diversity and antifungal susceptibility patterns in oral samples of HIV/AIDS patients in Baja California, Mexico

Candidiasis is the most common opportunistic fungal infection in HIV patients. The aims of this study were to identify the prevalence of carriers of Candida, Candida species diversity, and in vitro susceptibility to antifungal drugs. In 297 HIV/AIDS patients in Baja California, Mexico, Candida strains were identified by molecular methods (PCR-RFLP) from isolates of oral rinses of patients in Tijuana, Mexicali, and Ensenada. 56.3% of patients were colonized or infected with Candida. In Tijuana, there was a significantly higher percentage of carriers (75.5%). Out of the 181 strains that were isolated, 71.8% were Candida albicans and 28.2% were non-albicans species. The most common non-albicans species was Candida tropicalis (12.2%), followed by Candida glabrata (8.3%), Candida parapsilosis (2.2%), Candida krusei (1.7%), and Candida guilliermondii (1.1%). Candida dubliniensis was not isolated. Two associated species were found in 11 patients. In Mexicali and Ensenada, there was a lower proportion of Candida carriers compared to other regions in Mexico and worldwide, however, in Tijuana, a border town with many peculiarities, a higher carrier rate was found. In this population, only a high viral load was associated with oral Candida carriers. Other factors such as gender, use of antiretroviral therapy, CD4+ T-lymphocyte levels, time since diagnosis, and alcohol/ tobacco consumption, were not associated with Candida carriers.

Spectrum and the In Vitro Antifungal Susceptibility Pattern of Yeast Isolates in Ethiopian HIV Patients with Oropharyngeal Candidiasis

Background. In Ethiopia, little is known regarding the distribution and the in vitro antifungal susceptibility profile of yeasts. Objective. This study was undertaken to determine the spectrum and the in vitro antifungal susceptibility pattern of yeasts isolated from HIV infected patients with OPC. Method. Oral pharyngeal swabs taken from oral lesions of study subjects were inoculated onto Sabouraud Dextrose Agar. Yeasts were identified by employing conventional test procedures and the susceptibility of yeasts to antifungal agents was evaluated by disk diffusion assay method. Result. One hundred and fifty-five yeast isolates were recovered of which 91 isolates were from patients that were not under HAART and 64 were from patients that were under HAART. C. albicans was the most frequently isolated species followed by C. glabrata, C. tropicalis, C. krusei, C. kefyr, Cryptococcus laurentii, and Rhodotorula species. Irrespective of yeasts isolated and identified, 5.8%, 5.8%, 12.3%, 8.4%, 0.6%, and 1.3% of the isolates were resistant to amphotericin B, clotrimazole, fluconazole, ketoconazole, miconazole, and nystatin, respectively. Conclusion. Yeast colonization rate of 69.2% and 31% resistance to six antifungal agents was documented. These highlight the need for nationwide study on the epidemiology of OPC and resistance to antifungal drugs.

An in vitro study of antifungal drug susceptibility of Candida species isolated from human immunodeficiency virus seropositive and human immunodeficiency virus seronegative individuals in Lucknow population Uttar Pradesh

BACKGROUND

Candidiasis is the most common opportunistic infection in human immunodeficiency virus (HIV) seropositive patients, starting from asymptomatic colonization to pathogenic forms and gradual colonization of non-albicans in patients with advanced immunosuppression leads to resistance for azole group of antifungal drugs with high rate of morbidity and mortality.

OBJECTIVES

To isolate the Candida species and determine of antifungal drug susceptibility against fluconazole, itraconazole, nystatin, amphotericin B, and clotrimazolein HIV seropositive and control individuals, with or without clinical oropharyngeal candidiasis (OPC).

MATERIALS AND METHODS

Includes samples from faucial region of 70 subjects with and without clinical candidiasis in HIV seropositive and controls were aseptically inoculated onto Sabaraud's Dextrose Agar media and yeasts were identified for the specific species by Corn Meal Agar, sugar fermentation and heat tolerance tests. Antifungal drug susceptibility of the isolated species was done against above-mentioned drugs by E-test and disc diffusion method.

RESULTS

The commonly isolated species in HIV seropositive and controls were Candida albicans, Candida glabrata and Candida tropicalis Candida guilliermondii and Candida dubliniensis isolated only in HIV seropositive patients. Susceptibility against selected antifungal drugs was observed more in HIV-negative individuals whereas susceptible dose-dependent and resistance were predominant in HIV-positive patients.

CONCLUSION

Resistance is the major problem in the therapy of OPC, especially in HIV seropositive patients due to aggressive and prolonged use of antifungal agents, therefore, our study emphasizes the need for antifungal drug susceptibility testing whenever antifungal treatment is desired, especially in HIV-infected subjects.

Prevalence of oral candidiasis in HIV/AIDS children in highly active antiretroviral therapy era. A literature analysis

SummaryHighly active antiretroviral therapy has decreased the morbidity and mortality related to HIV infection, including oral opportunistic infections. This paper offers an analysis of the scientific literature on the epidemiological aspects of oral candidiasis in HIV-positive children in the combination antiretroviral therapy era. An electronic databases search was made covering the highly active antiretroviral therapy era (1998 onwards). The terms used were oral lesions, oral candidiasis and their combination with highly active antiretroviral therapy and HIV/AIDS children. The following data were collected from each paper: year and country in which the investigation was conducted, antiretroviral treatment, oral candidiasis prevalence and diagnostic parameters (clinical or microbiological). Prevalence of oral candidiasis varied from 2.9% in American HIV-positive children undergoing highly active antiretroviral therapy to 88% in Chilean HIV-positive children without antiretroviral therapy. With respect to geographical location and antiretroviral treatment, higher oral candidiasis prevalence in HIV-positive children on combination antiretroviral therapy/antiretroviral therapy was reported in African children (79.1%) followed by 45.9% reported in Hindu children. In HIV-positive Chilean children on no antiretroviral therapy, high oral candidiasis prevalence was reported (88%) followed by Nigerian children (80%). Oral candidiasis is still frequent in HIV-positive children in the highly active antiretroviral therapy era irrespective of geographical location, race and use of antiretroviral therapy.

Oral Cytology for HIV

Aim:

To asses morphological and morphometrical alterations of oral squamous epithelial cells in HIV infected individuals, and determine its diagnostic significance for HIV infection.

Materials and Methods:

Informed Consent was obtained from all study subjects. 40 adult HIV infected patients (experimental group) and 40 adult non-infected volunteers (control group) participated. Age, occupation, and relevant medical history were recorded. The following laboratory tests reports were recorded: complete blood cell counts, blood glucose levels, serum iron and erythrocyte sedimentation rate. Oral smears were collected from normal appearing tongue and buccal mucosa of the individuals by exfoliative cytology. The cells were morphologically analysed and the nuclear area (NA), the cytoplasmic area (CA) and the nucleus-to-cytoplasm area ratio (NA/CA) were calculated. Cell yield, cell cohesion, presence/absence of inflammatory cells and candida were observed.

Results:

The cytological smears of HIV patients showed abundant cell yield and the epithelial cells were found to be in close cohesive clusters and both findings were found to be statistically significant. Nuclear cytoplasmic ratio was seen to be increased in 93.8% of HIV positive patientsand Mild to moderate pleomorphism was observed in 17.9% of HIV positive patients. HIV positive patients had a diminished inflammatory response and this was found to be statistically significant.

Conclusion:

Statistically significant deviations from normal oral epithelium were found in the study conducted. With further research, oral exfoliative cytology may form a new, painless, inexpensive diagnostic method for HIV infections.

Growth inhibitory response and ultrastructural modification of oral-associated candidal reference strains (ATCC) by Piper betle L. extract

Candida species have been associated with the emergence of strains resistant to selected antifungal agents. Plant products have been used traditionally as alternative medicine to ease mucosal fungal infections. This study aimed to investigate the effects of Piper betle extract on the growth profile and the ultrastructure of commonly isolated oral candidal cells. The major component of P. betle was identified using liquid chromatography-mass spectrophotometry (LC-MS/MS). Seven ATCC control strains of Candida species were cultured in yeast peptone dextrose broth under four different growth environments: (i) in the absence of P. betle extract; and in the presence of P. betle extract at respective concentrations of (ii) 1 mg⋅mL(-1); (iii) 3 mg⋅mL(-1); and (iv) 6 mg⋅mL(-1). The growth inhibitory responses of the candidal cells were determined based on changes in the specific growth rates (µ). Scanning electron microscopy (SEM) was used to observe any ultrastructural alterations in the candida colonies. LC-MS/MS was performed to validate the presence of bioactive compounds in the extract. Following treatment, it was observed that the µ-values of the treated cells were significantly different than those of the untreated cells (P<0.05), indicating the fungistatic properties of the P. betle extract. The candidal population was also reduced from an average of 13.44×10(6) to 1.78×10(6) viable cell counts (CFU)⋅mL(-1). SEM examination exhibited physical damage and considerable morphological alterations of the treated cells. The compound profile from LC-MS/MS indicated the presence of hydroxybenzoic acid, chavibetol and hydroxychavicol in P. betle extract. The effects of P. betle on candida cells could potentiate its antifungal activity.

Antifungal susceptibility and growth inhibitory response of oral Candida species to Brucea javanica Linn. extract

Background

Candida species have been associated with the emergence of resistant strains towards selected antifungal agents. Plant products have been used traditionally as alternative medicine to ease candidal infections. The present study was undertaken to investigate the antifungal susceptibility patterns and growth inhibiting effect of Brucea javanica seeds extract against Candida species.

Methods

A total of seven Candida strains that includes Candida albicans ATCC14053, Candida dubliniensis ATCCMYA-2975, Candida glabrata ATCC90030, Candida krusei ATCC14243, Candida lusitaniae ATCC64125, Candida parapsilosis ATCC22019 and Candida tropicalis ATCC13803 were used in this study. The antifungal activity, minimum inhibitory concentration and minimum fungicidal concentration of B. javanica extract were evaluated. Each strain was cultured in Yeast Peptone Dextrose broth under four different growth environments; (i) in the absence and presence of B. javanica extract at respective concentrations of (ii) 1 mg/ml (iii) 3 mg/ml and (iv) 6 mg/ml. The growth inhibitory responses of the candidal cells were determined based on changes in the specific-growth rates (μ) and doubling time (g). The values in the presence of extract were computed as percentage in the optical density relative to that of the total cells suspension in the absence of extract.

Results

B. javanica seeds extract exhibited antifungal properties. C. tropicalis showed the highest growth rate; 0.319 ± 0.002 h^-1, while others were in the range of 0.141 ± 0.001 to 0.265 ± 0.005 h^-1. In the presence of extract, the lag and log phases were extended and deviated the μ- and g-values. B. javanica extract had significantly reduced the μ-values of C. dubliniensis, C. krusei and C. parapsilosis at more than 80% (ρ < 0.05), while others were reduced within the range of 2.28% to 57.05%. The g-values of most candidal strains were extended and significantly reduced (ρ < 0.05) in relative to the untreated. The candidal population was reduced from an average of 10 x 10⁶ to 6 x 10⁶ CFU/ml.

Conclusions

B. javanica extract exhibited in vitro antifungal activity against seven oral Candida species. The fungistatic and growth inhibiting effects of B. javanica extract have shown that it has potential to be considered as a promising candidate for the development of antifungal agent in oral health products.

Effects of eating disorders on oral fungal diversity

BACKGROUND

The eating disorders anorexia and bulimia nervosa can cause several systemic and oral alterations related to poor nutrition and induced vomiting; however, the oral microflora of these patients is poorly studied.

OBJECTIVE

The aim of this study was to evaluate fungal microflora in the oral cavity of these patients by culture-dependent and culture-independent methods.

STUDY DESIGN

Oral rinse samples were cultured to assess the prevalence of Candida species, and the isolates were identified by API system. Microorganism counts were compared by the Mann-Whitney test (5%). Ribotyping, a type of molecular analysis, was performed by sequencing the D1/D2 regions of 28S rRNA.

RESULTS

Our results demonstrated that the eating disorder group showed higher oral Candida spp. prevalence with culture-dependent methods and higher species diversity with culture-independent methods.

CONCLUSIONS

Eating disorders can lead to an increased oral Candida carriage. Culture-independent identification found greater fungal diversity than culture-dependent methods.

Oral Candida isolates among HIV-infected subjects in Nigeria

BACKGROUND

Nigeria is a West African country of more than 150 million persons with the second highest case of HIV/AIDS infected patients in the world. The species spectrum of oral yeast colonization and the susceptibility to a wide range of antifungal agents is poorly understood in Nigeria especially in the south east, south south, and the northern axis. This study evaluates the species spectrum of oral colonization by Candida species in HIV-infected patients in Nigeria and the in vitro susceptibility pattern of the Candida isolates to a broad range of antifungal agents.

METHODS

Two hundred oropharyngeal swabs from HIV-infected patients and 100 age-matched healthy controls were screened for yeast isolates using standard procedures and confirmed by the analytical profile index 20C along with other biochemical tests. In vitro susceptibility testing of the yeast isolates to antifungals were performed using the broth microdilution method protocol recommended by the Clinical Laboratory Scientific Institute.

RESULTS

Of 200 patients screened, 120 (60%) were colonized by yeasts. C albicans was the dominating species in both groups with 54 (45%) isolated from HIV subjects. The non-albicans Candida species accounted for 55% with C tropicalis 22 (18.3%) showing the highest frequency. We observed that 11.7% of all yeasts isolates were resistant to fluconazole, 8.3% to flucytosine, 7.5% to itraconazole, and 1.7% to voriconazole. All isolates were susceptible to amphotericin B and most of them demonstrated very low voriconazole minimal inhibitory concentrations. Apart from C albicans, C tropicalis and C parapsilosis isolates were also recovered from apparently healthy control subjects.

CONCLUSION

Although C albicans continues to be the dominant Candida species in oral Candida carriage of HIV-infected patients in Nigeria, the nonalbicans Candida species are increasing. Furthermore, the finding of resistant isolates in our study emphasizes the need for antifungal susceptibility testing whenever antifungal treatment is desired especially in HIV-infected subjects.

QSAR studies of a number of triazole antifungal alcohols

The activity of fungicide agents containing a quinazolinone ring was described using the quantitative structure-activity relationship (QSAR) model by applying it to data taken from literature. The title compounds exhibit two important types of activity against certain fungal pathogens, i.e. activity against yeast and activity against filamentous fungi. A correlation between both antifungal activities (e.g. FA(yst) and FA(ff)) and physicochemical parameters such as the logarithm of the n-octanol/water partition coefficient (log P), the polarizability (P), the global minimum energy (TE), the energy difference between the frontier molecular orbital (DELH) and the molar refractivity (MR), was established using multiple linear regression. The molecular descriptors of the antifungal agents were obtained by quantum chemical calculations combined with molecular modeling calculations. Statistical analysis shows that the antifungal activity depends mainly on the calculated partition coefficients, log P, of the compounds. Bi-parametric models reveal that antifungal activity relates linearly to log P and P.

Levels of salivary IgA antibodies to Candida spp. in HIV-infected adult patients: a systematic review

OBJECTIVE

To perform a systematic review of published data with the aim of evaluating the levels of IgA antibodies to Candida albicans in HIV-infected adult patients.

METHODS

The search strategy was based on PubMed, Web of Science, Google Scholar, Cochrane and EMBASE databases. Also, the reference lists of included studies were searched. All abstracts found by electronic searches were independently scrutinized by two reviewers. To be eligible for review, the controlled studies had to present the following characteristics: samples of both HIV-infected adults and noninfected adults; appropriate HIV-diagnostic tests for both patient groups (case and control); IgA-diagnostic test applied to a similar population sample.

RESULTS

Of 144 studies found, only six met the initial eligibility criteria, but three were excluded after a thorough analysis. To assess the methodological quality of the three remaining studies, they were categorized according the risk of bias. The three selected studies revealed that the levels of C. albicans-specific IgA antibody were higher in HIV-infected individuals compared with the control group.

CONCLUSION

Adequate IgA antibody responses to C. albicans appear to be maintained, since the levels of these antibodies were higher in all studies selected. Although the findings of this systematic review are encouraging, the scientific evidence should be interpreted carefully because there are only a few reports in the literature, mostly because of the lack of important methodological details or the varying methodologies employed.

Evaluation of CHROM-Pal medium for the isolation and direct identification of Candida dubliniensis in primary cultures from the oral cavity

Candida albicans is the species most frequently isolated from oral specimens, but the recovery of other Candida species such as Candida dubliniensis is increasing. Differentiation of C. dubliniensis from C. albicans requires special tests and both species are misidentified in some studies. CHROM-Pal (CH-P) is a novel chromogenic medium used in our laboratory for differentiation between C. albicans and C. dubliniensis on the basis of colony colour and morphology, and chlamydospore production. The performance of CH-P and CHROMagar Candida (CAC) was compared for primary isolation and presumptive identification of yeasts from oral specimens from human immunodeficiency virus (HIV)-infected and uninfected individuals. The identification of Candida species on both media was compared with two reference identification methods (API ID 32 C and multiplex PCR). A total of 137/205 oral swabs (66.8 %) plated onto CH-P and CAC media were positive by culture and resulted in the growth of 171 isolates of Candida species on CH-P, whilst only 159 isolates grew on CAC. C. albicans was the most frequently isolated species in both groups of patients, followed by Candida parapsilosis in the HIV-negative group, and by C. dubliniensis in the HIV-infected group. The other Candida species isolated were Candida guilliermondii, Candida glabrata, Candida krusei, Candida tropicalis, Candida famata, Candida rugosa, Candida kefyr, Candida pelliculosa and Candida pulcherrima. The sensitivity and specificity for identifying C. albicans, C. krusei, C. tropicalis and C. dubliniensis on CH-P were over 98.5 %, always equal to or higher than those obtained when CAC was used. CH-P is a simple reliable medium for primary isolation and presumptive identification of yeast isolates from oral samples. The ability of CH-P to discriminate between C. dubliniensis and C. albicans was significantly higher (P <0.05) than that of CAC.

Incidence and anatomic localization of oral candidiasis in patients with AIDS hospitalized in a public hospital in Belo Horizonte, MG, Brazil

The objective of this study was to evaluate the incidence, anatomic localization and yeast species isolated from each clinical type of oral candidiasis. The clinical samples were obtained from 67 patients with AIDS with CD4 cell counts below 200 cells/mm³ and hospitalized in a public hospital (Eduardo de Menezes Hospital) in the city of Belo Horizonte, MG, Brazil. Yeasts were isolated using Chromagar® Candida. The results show that 50.7% of these patients had oral candidiasis. The pseudomembranous form was the most frequent clinical manifestation of oral candidiasis, followed by the erythematous and angular cheilite forms. The most common site of these clinical forms of oral candidiasis was the tongue. Candida albicans was the most common yeast species isolated from the lesions. However, other species were also found to be associated with these forms of oral candidiasis.

Erythematous candidosis in patients with complete dentures and HIV+/AIDS

This investigation was designed to evaluate the frequency of erythematous candidosis (EC) and Candida species, proteinase and phospholipase exoenzyme production, and to compare clinical features in patients with complete dentures and HIV+/Acquired Immunodeficiency Disease Syndrome (AIDS). Fifty-one patients were selected from a total of 285 with EC: denture wearers (n = 30) and HIV+/AIDS (n = 21). The yeast prevalence and the production of exoenzymes, such as proteinase and phospholipase by Candida species were evaluated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) electrophoresis. The frequency of Candida albicans was significantly higher (P < 0.05) in both groups although other yeast species (Candida glabrata, Candida krusei, Candida parapsilosis, Candida guilliermondi and Candida tropicalis) were also found. Candida albicans showed greater levels of proteinase production in the denture wearers, when compared with the HIV+/AIDS group. There was no difference between groups with regard to phospholipase production. The protein bands presented similar molecular weights, showing the presence of proteinases in both groups. It could be concluded that the clinical manifestation of EC may be related to its proteinase production capacity. Combination therapies using proteinase inhibitors play an important role in inhibiting exoenzyme production by Candida species, mainly C. albicans.