Immunology of oral candidiasis

Characterization of oral candidiasis according to antiretroviral treatment status, immunological and virological profiles among HIV infected patients in two health facilities in Yaoundé-Cameroon: a cross-sectional and analytical study

Introduction

oral candidiasis in HIV-disease generally indicates immune incompetence both among antiretroviral treatment (ART) naive and experienced patients. To optimize oral healthcare among people living with HIV (PLHIV) in sub-Saharan Africa (SSA), we sought to evaluate the type and distribution of oral candidiasis with respect to ART-profile and immuno-virological parameters among PLHIV in the Cameroonian context.

Methods

a cross-sectional study was conducted among 163 patients (51 ART-naïve and 112 ART-experienced) residing in Yaoundé, Cameroon, from February through May 2019. Oral candidiasis was assessed, while viral load (VL) and CD4-count were measured on Abbott m2000rt and Cy-flow counter platforms, respectively. Data were analyzed using the Statistical Package for the Social Sciences (SPSS) v.21 with p<0.05 considered statistically significant.

Results

in all, 18 cases of two forms of oral candidiasis were identified (13 erythematous and 5 pseudomembranous), with the majority, 27.7% (11/51), observed among ART-naïve patients against 6.3% (7/112) in ART-experienced (p=0.006). With respect to immuno-virological profile, 77.8% (14/18) and 22.2% (4/18) of cases were identified among participants with CD4<200 cells/mm3 and CD4>200 cells/mm3, respectively (p<0.0001). In the light of viral load, the occurrence of oral candidiasis was largely observed among subjects with VL≥1000 copies/ml, 83.3% (15/18), against 16.7% (3/18), with VL<1000 copies/ml, irrespective of the candidiasis form (p<0.0001).

Conclusion

among PLHIV, erythematous and pseudomembranous candidiasis are commonly found in the absence of ART, driven by immunodeficiency and active viral replication. In spite of the protective role of ART, PLHIV experiencing immuno-virological failure should be referred for management of oral candidiasis.

Effect of Cigarette and E-Cigarette Smoke Condensates on Candida albicans Biofilm Formation and Gene Expression

Smoking triggers environmental changes in the oral cavity and increases the risk of mucosal infections caused by Candida albicans such as oral candidiasis. While cigarette smoke has a significant impact on C. albicans, how e-cigarettes affect this oral pathogen is less clear. Here, we investigated the effect of cigarette and e-cigarette smoke condensates (CSC and ECSC) on C. albicans growth, biofilm formation, and gene expression. Whereas pure nicotine (N) at the minimum inhibitory concentration (MIC, 4 mg/mL) prevented C. albicans growth, enhanced biofilm formation was observed at 0.1 mg/mL. In contrast, at this nicotine sub-MIC (0.1 mg/mL) concentration, CSC and ECSC had no significant effect on C. albicans biofilm formation. Additionally, N, CSC, and ECSC increased the expression of HWP1 and SAP2 genes. The ECSC group exhibited elevated expression levels of the EAP1 and ALS3 genes, compared to the nicotine-free ECSC (-) control. Moreover, our in vitro study illustrated that the antifungal drugs, fluconazole and amphotericin B, alleviated the effect of nicotine on C. albicans gene expression. Overall, the results of the study indicated nicotine from different sources may affect the pathogenic characteristics of C. albicans, including hyphal growth, biofilm formation, and particularly the expression of virulence-related genes.

Microbial interactions and immunity response in oral Candida species

Oral candidiasis are among the most common noncommunicable diseases, related with serious local and systemic illnesses. Although these infections can occur in all kinds of patients, they are more recurrent in immunosuppressed ones such as patients with HIV, hepatitis, cancer or under long antimicrobial treatments. Candida albicans continues to be the most frequently identified Candida spp. in these disorders, but other non-C. albicans Candida are rising. Understanding the immune responses involved in oral Candida spp. infections is a key feature to a successful treatment and to the design of novel therapies. In this review, we performed a literature search in PubMed and WoS, in order to examine and analyze common oral Candida spp.-bacteria/Candida-Candida interactions and the host immunity response in oral candidiasis.

Oral Candida Mannan Concentrations Correlate with Symptoms/Signs of Ill Health and the Immune Status

BACKGROUND

A relationship has been proposed between increases in oral Candida concentrations and host immunity. Therefore, the present study was conducted to investigate the relationship between oral Candida mannan concentrations and symptoms/signs of ill health and the immune status and also to examine whether health/the immune status may be evaluated based on oral Candida mannan concentrations.

PATIENTS AND METHODS

The health conditions of 25 healthy individuals and 10 cancer patients receiving cytotoxic chemotherapy were assessed using a questionnaire and oral rinse solutions collected on consecutive days. Candida mannan concentrations in oral rinse solutions were measured using a commercial sandwich ELISA kit.

RESULTS

The use of dentures was identified as a significant independent factor increasing Candida mannan concentrations. In a stratified analysis based on the use of dentures, significantly increased Candida mannan concentrations were detected in healthy volunteers with chills and in cancer patients with slight/moderate fever (37.5-38.4 °C) (multivariate analysis, p < 0.01) who were non-denture users. These symptoms/signs may be associated with (pre-)infection, during which the immune system is activated and needs to function well.

CONCLUSIONS

The present results suggest that oral Candida mannan concentrations are a predictive marker for health/the immune status.

Relationship Between the Quantity of Oral Candida and Systemic Condition/Diseases of the Host: Oral Candida Increases with Advancing Age and Anemia

BACKGROUND

The impact of host systemic conditions/diseases on the prosperity of oral Candida colonies remains unclear. The aim of the present study was to investigate whether a relationship exists between the quantity of oral Candida and the systemic condition/diseases of the host.

PATIENTS AND METHODS

The cross-sectional relationship between Candida mannan concentrations and health check-up results was analyzed in consideration of local conditions that influence the prevalence of oral Candida.

RESULTS

Candida mannan concentrations correlated with age, the number of untreated decayed teeth, number of prosthetic teeth, salivary pH, HbA1c, and the red blood cell count in a univariate analysis. In a multivariate analysis, Candida mannan concentrations correlated with age, the number of untreated decayed teeth, number of prosthetic teeth, salivary pH, and the red blood cell count. Candida mannan concentrations were higher in subjects older than 80 years, with a higher number of either untreated or prosthetic teeth, with a lower salivary pH, and with a decreased red blood cell count. Mannan concentrations were slightly higher in subjects with elevated HbA1c.

CONCLUSIONS

The present results suggest a close relationship between the quantity of oral Candida and the systemic condition/diseases of the host. Oral Candida may increase in immunocompromised hosts.

Clinico-mycological analysis and antifungal resistance pattern in human immunodeficiency virus-associated candidiasis: An Indian perspective

Objectives:

Candidiasis is a common human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome-associated opportunistic mycoses. The present study ascertained the species spectrum of Candida strains recovered from different clinical samples from symptomatic HIV-positive individuals and determined the antifungal susceptibility profile of the isolates.

Materials and Methods:

A variety of specimens were collected from 234 symptomatic HIV seropositive individuals depending on their clinical manifestations and subjected to direct microscopic examination. Blood samples were inoculated in biphasic blood culture medium and all other specimens on Sabouraud dextrose agar with chloramphenicol and incubated at 35°C–37°C. Species identification of the recovered Candida isolates was attempted on the basis of germ tube production, micromorphology on corn meal agar, color and morphology on HiCrome Candida Differential agar, and carbohydrate fermentation and assimilation tests. Susceptibility testing of the isolates was performed employing the VITEK 2 system.

Results:

A total of 167 Candida isolates were obtained; Candida albicans (136), Candida tropicalis (13), Candida krusei (8), Candida parapsilosis (5), Candida glabrata (4), and Candida kefyr (1). Fluconazole resistance was more frequent among nonalbicans species, and significantly higher 5-fluorocytosine resistance compared to C. albicans was also observed. Eight Candida strains (six C. krusei, one C. kefyr, and one C. albicans) were multidrug resistant.

Conclusion:

Although C. albicans continues to be the leading etiological agent of candidiasis, the incidence of nonalbicans species among HIV-positive Indian individuals is rising. Antifungal resistance was higher among nonalbicans Candida species. Another issue of therapeutic concern is the possible emergence of multidrug-resistant Candida strains among these patients.

An in vitro study of isolation of candidal strains in oral squamous cell carcinoma patients undergoing radiation therapy and quantitative analysis of the various strains using CHROMagar

Background:

Patients undergoing radiation therapy for oral squamous cell carcinoma (OSCC) have an increased risk of developing oral candidiasis. Radiation-induced hyposalivation is thought to be a major predisposing factor for it. Radiation therapy for 2–3 weeks leads to increase in the number of candidal species in the oral cavity, eventually leading to oral candidiasis.

Objective:

To evaluate and correlate the prevalence of candidal species in the oral cavity of OSCC patients and to compare with radiation dosage at 3^rd and 6^th week following radiotherapy.

Materials and Methods:

This study includes fifty patients undergoing radiation therapy for OSCC. Patients were examined at 3^rd and 6^th week following radiation therapy, and smear samples were obtained from lesional sites and the radiation dose was recorded. Smear samples were cultured on CHROMagar, and identification of various candidal species was done on the basis of colony color and their morphology.

Results:

The present study isolated four types of candidal species, namely, Candida albicans, Candida glabrata, Candida tropicalis and Candida krusei. All the organisms, except C. krusei, showed a significant increase from 3^rd to 6^th week of radiotherapy whereas C. glabrata and C. tropicalis showed a sudden exponential increase. Total radiation dosage did not show any correlation to candidal colonization at 3^rd and 6^th week following radiotherapy.

Conclusion:

OSCC patients undergoing radiotherapy show an increase in candidal colonization which is independent of radiation dosage and may be related to other factors. However, such findings should be further evaluated using a larger sample size.