Oral Candidal Carriage Research Articles

Oral Candida isolates among HIV-infected subjects in Nigeria

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. 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. 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. 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.

Prevalence of Candida dubliniensis among Oral Candida Isolates in Patients Attending the Kuwait University Dental Clinic

Objectives: The aim of this study was to determine the oral candidal carriage of patients seeking dental treatment at the Kuwait University Dental Clinic and to ascertain the Candida species composition among them. Methods: 370 oral rinse samples were collected from patients. The germ tube test, CHROMagar Candida medium and VITEK 2 yeast identification system were used for species identification. C. dubliniensis isolates were confirmed by the production of rough colonies with hyphal fringes and chlamydospores on simplified sunflower seed agar. Results: Of the 370 samples investigated, 160 (43.24%) showed Candida in culture. The isolation of Candida was significantly higher in individuals who were smokers or were under medication for either diabetics or asthma [99 (62%)] compared to healthy individuals [61 (38%)]. Of the 210 samples which did not yield Candida, 131 (62.38%) were healthy and 79 (37.62%) were associated with smoking or with usage of drugs for aforementioned conditions. Species isolated were C. albicans [102 (63.7%)], C. dubliniensis [23(14.3%)], C. krusei [13 (8.1%)], C. tropicalis [12 (7.5%)] and C. glabrata [10 (6.2%)]. Conclusions:Candida species were more prevalent in patients having predisposing factors implicated in oral candidosis, such as in smokers, diabetic patients and asthmatic patients using inhalation steroids. C. albicans was the most prevalent species isolated, followed by C. dubliniensis.

Experiments on in vivo biofilm formation and in vitro adhesion of Candida species on polysiloxane liners

Microorganisms may colonise polysiloxane soft liners leading to bio-deterioration. The aim of this study was to investigate in vitro adhesion and in vivo biofilm formation of Candida species on polysiloxane surfaces. The materials used in this study were Molloplast B, GC Reline soft, Mollosil Plus, Silagum Comfort and Palapress Vario. The in vitro retention of clinical isolates of Candida albicans to the relining and denture-base materials by microscopic (scanning electron microscopy, SEM), conventional culturing methods and antimicrobial properties of these materials were studied. Candida found on materials and mucosa following long-term use were identified and quantified, and biofilms covering the surfaces were investigated by SEM. There was a significant decrease in the number of cells attached in vitro to saliva-coated surfaces compared with non-treated surfaces. An oral Candida carriage of 78% was found. Candida albicans, C. glabrata, C. intermedia and C. tropicalis were identified. In vivo biofilm formation on the liners appeared as massive colonisation by microorganisms. The results of the in vitro experiments suggest that salivary film influences early colonisation of different C. albicans strains. The film layer also minimises the differences among different strains. The Candida carriage of these patients was similar to denture-wearing patients without soft liners.

Salivary Glucose Levels are Unable to Predict Oral Candidiasis or Monitor Diabetes

Salivary glucose levels and oral candidal carriage in type II diabetics. Sashikumar R, Kannan R. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010;109(5):706-11. Wenche S. Borgnakke, DDS, MPH, PhD. (1) What is the relationship between salivary glucose and oral candida carriage? and (2) Can salivary glucose levels be used to monitor diabetes control? The Chennai Dental Research Foundation, India. Cross-sectional Level 2: Limited-quality, patient-oriented evidence. Not applicable.

Association of Oral Candidal Carriage with Dental Caries in Children

Introduction: Oral candidiasis is one of the most common opportunistic oral fungal infections. Oral candidal carriage in schoolchildren is a subject of increasing interest worldwide and has recently been associated with increased caries incidence in children. Aims: This study was carried out to identify association between oral candidal carriage in children and dental caries. Subjects and Methods: One hundred subjects with an age range between 6 and 12 years were included in this study. The subjects were distributed equally into two groups, i.e., study (caries-positive) and control (caries-free) groups. Oral hygiene index and DMFT/dmft scores were recorded for each subject. Sampling for Candida was carried out using intraoral swabs and concentrated oral rinse. Sabouraud dextrose agar containing 0.1 mg/ml of chloramphenicol was used as the primary culture medium. Candida was identified by employing API-20C AUX and germ tube formation tests. Results: The subjects in the caries-positive group showed a high frequency of oral candidal carriage compared to the caries-free subjects and the results were statistically very significant (p < 0.01). The odds ratio was 67.37, implying a high caries risk with positive oral candidal carriage (95% CI 14–323). Discussion: The findings of this study underscore the possible association of Candida with dental caries. Conclusions: The occurrence of dental caries in children with mixed dentition is positively correlated with the frequency of oral candidal carriage.

Salivary glucose levels and oral candidal carriage in type II diabetics

The aim of this study was to detect salivary glucose levels in diabetic and nondiabetic subjects, to study the relationship between salivary glucose levels and salivary candidal carriage, and to determine if salivary glucose levels could be used as a noninvasive tool to monitor glycemic control in diabetics. A total of 150 adults, 100 with type 2 diabetes and 50 without diabetes (control subjects), aged 40-60 years, participated in the study. Diabetic status was determined by estimation of random nonfasting plasma glucose levels and glycosylated hemoglobin levels. Both unstimulated and stimulated saliva were collected and investigated for glucose levels and colony-forming units (CFU) of Candida. Salivary glucose levels were measured using the glucose-oxidase method. Salivary glucose levels were significantly higher in diabetics than nondiabetics. There was a significant positive correlation between salivary and plasma glucose levels. Candidal CFUs were significantly higher in diabetic subjects and showed a significant positive correlation with salivary (unstimulated and stimulated) glucose levels. These results show that salivary glucose concentration is a potentially useful noninvasive tool to monitor glycemic control in diabetic patients. Increased salivary glucose is associated with increased prevalence of oral Candida in these subjects.

Oral Candida carriage of patients attending a dental clinic in Braga, Portugal

Background The ability of the Candida species to colonize surfaces can be considered as a risk factor for oral infection. Aims To establish oral Candida carriage in patients attending a dental clinic in Braga, Portugal. Methods A total of 97 patients were analysed. Swab samples were collected and directly cultured onto CHROMagar Candida. Representative yeasts were identified by polymerase chain reaction. Results From the samples analysed 54.6% ( n=53) were Candida positive, and Candida albicans was the most frequently isolated species, accounting for 79% of all the species identified. Non- C. albicans Candida (NCAC) species recovered included Candida parapsilosis, Candida glabrata, Candida tropicalis, and Candida guilliermondii. There was a lack of association between the presence of C. albicans or NCAC species, and age, gender, or prostheses wearing in this population. In 17% of the cases ( n=9), polymicrobial cultures, with two different Candida species, were identified. Conclusions This study shows a high Candida carriage rate among this population, thus pointing to the relevance of an accurate diagnostic approach in Candida species identification.

The relationship between oral hygiene and oral colonization with Candida species in healthy adult subjects*

Poor oral hygiene has been frequently suggested as a predisposing factor for oral candidal colonization, but the convincing evidence is lacking. To assess and compare oral candidal colonization, both quantitatively and qualitatively, in groups of healthy dentate subjects with different levels of oral hygiene as determined by the plaque index (PI) and gingival index (GI) scores. The concentrated oral rinse technique was used to isolate Candida species from 149 healthy dentate subjects. Candida species were cultured on Sabouraud's dextrose agar plates and identified by germ-tube test and the automated Vitek(R) system biochemical yeast card. According to the PI and GI scores, subjects were divided into different groups of oral hygiene level. Candida species were isolated from 86 (57.7%) subjects. The prevalence of candidal carriage increased significantly as a function of age (P = 0.023), but was comparable between males and females (58.7% and 56.7% respectively; P = 0.87). Oral candidal carriage rate and density were not affected by the levels of dental plaque or gingival condition. The prevalence of oral candididal carriage was significantly higher in the subjects who were not using dental floss compared with those who were using dental floss (P = 0.032). Oral hygiene status, as determined by the PI and the GI scores per se, does not affect oral candidal colonization in healthy dentate subjects.

Selective Expression of Human Immunodeficiency Virus Nef in Specific Immune Cell Populations of Transgenic Mice Is Associated with Distinct AIDS-Like Phenotypes

We previously reported that CD4C/human immunodeficiency virus (HIV)(Nef) transgenic (Tg) mice, expressing Nef in CD4(+) T cells and cells of the macrophage/dendritic cell (DC) lineage, develop a severe AIDS-like disease, characterized by depletion of CD4(+) T cells, as well as lung, heart, and kidney diseases. In order to determine the contribution of distinct populations of hematopoietic cells to the development of this AIDS-like disease, five additional Tg strains expressing Nef through restricted cell-specific regulatory elements were generated. These Tg strains express Nef in CD4(+) T cells, DCs, and macrophages (CD4E/HIV(Nef)); in CD4(+) T cells and DCs (mCD4/HIV(Nef) and CD4F/HIV(Nef)); in macrophages and DCs (CD68/HIV(Nef)); or mainly in DCs (CD11c/HIV(Nef)). None of these Tg strains developed significant lung and kidney diseases, suggesting the existence of as-yet-unidentified Nef-expressing cell subset(s) that are responsible for inducing organ disease in CD4C/HIV(Nef) Tg mice. Mice from all five strains developed persistent oral carriage of Candida albicans, suggesting an impaired immune function. Only strains expressing Nef in CD4(+) T cells showed CD4(+) T-cell depletion, activation, and apoptosis. These results demonstrate that expression of Nef in CD4(+) T cells is the primary determinant of their depletion. Therefore, the pattern of Nef expression in specific cell population(s) largely determines the nature of the resulting pathological changes.

Enhancement of Candida albicans Virulence After Exposition to Cigarette Mainstream Smoke

The habit of cigarette smoking is associated with higher oral candidal carriage and possible predisposition to oral candidosis. The effects of exposure to smoke on the virulence properties of oral yeasts remain obscure. Hence, we showed in vitro the effect of cigarette smoke condensate (CSC) on ten clinical isolates of Candida albicans obtained from nonsmoking volunteers, as well the type-strain CBS562. CSC was generated by complete burn of five commercial cigarettes in an in-house smoking machine and used to prepare the culture broth in which the strains were grown. In 24-h intervals (T(24), T(48), and T(72)), the cells were harvested, washed, subcultured, and the resultant growth were evaluated for possible variations for secreted aspartyl protease, phospholipase, chondroitinase, and hemolysins, adhesion to acrylic and cell surface hydrophobicity (CSH). The results indicated a temporal increase in the secretion rates of enzymes, particularly when yeast cells were exposed to CSC for 48-72 h (P < 0.05). Similarly, adhesion to acrylic and CSH increased with exposure period (P < 0.05). Based on foregoing, we concluded that CSC may promote significant enhance in the secretion of candidal histolytic enzymes and adherence to denture surfaces, thereby promoting oral yeast carriage and possible infection.

The role of salivary factors in persistent oral carriage of Candida in humans

Background Candida albicans is a commensal oral yeast in approximately one-third to one-half of the healthy population. To date, there are no studies investigating the multiple anti-candidal salivary constituents of healthy individuals with either nil or, consistent oral yeast carriage. Objective To compare the composition and anti-candidal activity in stimulated whole saliva of healthy ‘consistent’ oral Candida carriers with Candida-free individuals. Methods A sub-sample of 22 consistent, Candida-free individuals and 10 consistent Candida carriers were recruited from a 12 months screening study investigating oral Candida carriage in 97 healthy patients treated by fixed orthodontic appliances. Unstimulated and stimulated saliva samples were collected. The following salivary attributes were measured using standard methodology: the flow rate, pH, lysozyme, lactoferrin and IgA concentration and, the degree of inhibition of blastoconidial growth and blastospore germination. Results Saliva from the Candida-free individuals showed 20.2% higher inhibition of blastoconidial growth ( p < 0.05) of a reference strain of Candida albicans. No significant differences between the other salivary attributes of the two groups were found. Conclusion The fact that saliva of Candida-free individuals significantly inhibited the blastoconidial growth more than Candida-carriers ( p < 0.05) suggests that saliva may play a role in modulating oral candidal populations in health. Further studies, with a larger cohort are needed to confirm these findings and determine the factors that confer enhanced salivary anti-candidal activity.

Prevalence of oral Candida carriage in denture wearers

Prevalence of oral Candida carriage in denture wearers

Oral Candida infection and colonization in solid organ transplant recipients

Oral Candida carriage and infection have been reported to be associated with a greater risk for systemic infection in transplant recipients; however, a systematic analysis of the oral Candida titers and species has not been previously conducted. The objectives of this study were to determine the prevalence of oropharyngeal candidiasis, the oral carrier status, Candida titers and species in this population. Ninety kidney and heart transplant subjects and 72 age-matched healthy controls were included. Swabs from the oral mucosa and a standardized amount of unstimulated saliva were plated on Chromagar Candida, and colony-forming units per millilitre were calculated. Initial speciation was based on colony color and was confirmed by standard germ tube, biotyping, or polymerase chain reaction assays. Infection with C. albicans was detected in seven transplant subjects and none of the controls. The transplant group had significantly higher oral Candida titers than the control group. There were no statistically significant relationships between the dose or type of immunosuppressants and oral Candida titers or infection. A significantly higher percentage of transplant subjects were colonized by more than one species, compared with control subjects. The most frequent species combination in transplant subjects was C. albicans and C. glabrata. C. glabrata was isolated from 13.5% of transplant carriers and none of the controls. Increased oral Candida infection and carriage titers were found in the transplant population. Although the majority of transplant patients were colonized by C. albicans, C. glabrata appears to emerge as the second most prevalent species.

Commensal Oral Candida in Asian Cohorts

The oral carriage rate of Candida in healthy humans ranges from 40% to 60%. However for a prolonged period, the oral candidal prevalence in humans was documented essentially using data from studies in the West as their prevalence in inhabitants in different regions of the world, including Asia was not known. Yet, recent reports from a number of studies indicate the quality, quantity and prevalence of oral yeasts differ between Asia and other regions for reason that are still unclear. This mini review on such data from Asian studies on oral carriage of Candida provides another intriguing facet of the behavior of this ubiquitous yeast.

Carriage ofCandidaspecies in oral cavities of HIV infected patients in South India

Fifty-four patients with human immunodeficiency virus (HIV) infection were studied to assess the load of oral carriage of Candida spp. The mean oral Candida carriage density (30,305.93 +/- 56,643.93 CFU ml(-1)) in HIV patients was significantly higher than that seen in the control population (93.48 +/- 358.48 CFU ml(-1); P = 0.000). The mean Candida load in HIV patients with oral thrush (46,591.43 +/- 65,002.57 CFU ml(-1)) was significantly higher than in the HIV subjects without oral thrush (306.32 +/- 699.50 CFU ml(-1); P = 0.000). Non-C. albicans Candida species (56%) were more predominant than the C. albicans (44%) isolates. 25S rDNA PCR analysis of C. albicans revealed preponderance of genotype A strains. Interestingly, 42.6% of rinse specimens grew multiple Candida species, with the combination of C. albicans and C. krusei (39.1%) being the most frequent.

Factors affecting the prevalence of yeasts in the oral cavity of patients with diabetes mellitus

Objective To investigate fungal flora of the oral cavity as well as the influence of denture, smoking, antibiotic and corticosteroid therapies on oral yeasts of patients with diabetes mellitus. Patients and methods Oral samples, which were obtained from 132 diabetic patients and 130 healthy controls, were cultured on selective media, in order to isolate, count and identify the yeasts. Results All the diabetic patients carried significant amounts of yeast cells, especially Candida albicans, in the oral cavities compared to healthy subjects ( P < 0.05). A total of four major yeast genera including six Candida species were isolated from the patients including C. albicans (22.4%), C. glabrata (10%), C. tropicalis (5.4%), C. dubliniensis (4.4%), C. krusei (2%), C. pseudotropicalis (1.6%), Saccharomyces spp. (0.6%), Rhodotorula spp. (0.4%) and Trichosporon spp. (0.2%). These organisms were recovered at higher densities in diabetics wearing dentures and receiving antibiotics compared to those suffering other predisposing factors ( P < 0.05). Saliva and tongue were the commonest sites of yeast colonization into the oral cavity in all population. The relationship between the yeast colony count mean and blood sugar was significant ( P < 0.05), whereas there was no significant relationship between oral yeast density and salivary sugar. Conclusion Regarding the high frequency of oral candidal carriage in diabetic patients, hygienic condition in the oral cavity of the patients and using local antiseptic and antifungal agents are necessary.

Oral Candida colonization of human immunodeficiency virus infected subjects in Turkey and its relation with viral load and CD4+ T‐lymphocyte count

The association of asymptomatic oral Candida colonization with the markers of immunodeficiency and HIV is not clear yet. In addition, the prevalence of different Candida species colonizing the oral cavity of HIV-infected patients in Turkey remains unknown. To evaluate these subjects, oral rinse samples were taken from 64 HIV-positive individuals who have come to the department of Microbiology and Clinical Microbiology, Istanbul Medical Faculty for viral load and CD4(+) T-lymphocyte count measurement. The specimens were plated quantitatively on CHROMagar Candida. Oral Candida colonization was detected in 53 (82.8%) patients. The species isolated most frequently from carriers was Candida albicans (83%), followed by Candida glabrata (22.6%) and Candida dubliniensis (11.3%). More than one Candida spp. was isolated from 16 (30%) colonized patients. The status of yeast carriage and Candida load was not associated with the number of CD4(+) cells or the viral load. Similarly, there was no statistical relation between the use of protease inhibitors, age, gender, smoking and the oral carriage of Candida. Other factors, which may be responsible for the high oral carriage of Candida spp. in this patient group, need to be researched.

Oral candidal carriage and biotyping of Candida species in HIV positive patients

To investigate the candidal carriage and the Candida species in HIV positive patients and to explore the relationship between oral candidal carriage and oral candidiasis. Sixty-four HIV positive patients and 42 healthy controls were included in this study. Oral rinse technique was used to detect the candidal carriage. The isolates were identified using multiple measures, including Gram staining reaction, chlamydospore, pseudo-hyphal and hyphal production test, CHROMagar Candida test and API 20 C AUX yeast identification system. Thirty-nine of 64 HIV positive cases were diagnosed as oral candidiasis. Seventy-four Candida strains were isolated from 52 of 64 HIV positive cases, only 7 strains were isolated from 42 healthy controls (P < 0.001). Of the 74 Candida strains isolated from HIV positive cases, 39 were Candida albicans, 15 Candida tropicalis, and 20 other 6 species. A high prevalence of oral candidiasis and high candidal carriage were found in HIV positive patients compared with those in controls. Candida albicans and Candida tropicalis were the major species. The biotyping of the species isolated from HIV positive patients showed more diversified compared to healthy people, which may suggest the decreased immune ability of the HIV positive patients.

One‐year follow‐up of the effect of fixed orthodontic treatment on colonization by oral candida

The aim of this study was to assess quantitative and qualitative alterations in the carrier rate of Candida spp. in south-eastern Turkey among adolescents, and to investigate the effect of fixed orthodontic appliances on the Candida count in a 1-year follow-up study. In the first phase of the study, the oral Candida carriage rate of 72 patients was evaluated. Samples were collected from the dorsal surface of the tongue, the mid-palate and saliva. In the second phase of the study, 42 patients who were determined to be carriers of oral Candida were treated with fixed orthodontic appliances, and from these patients a second set of samples were collected from the saliva and the orthodontic brace surfaces of eight teeth adjacent to the enamel surfaces. The saliva samples were collected before and during orthodontic treatment at 1st, 6th and 12th month, and samples from the braces were collected during the 1st, 6th and 12th month of treatment. Forty-two of the 72 patients (58.5%) were oral Candida carriers. The distribution of Candida spp. in these patients was as follows: (i) Candida albicans was identified in 31 patients (73.8%), (ii) C. tropicalis, C. krusei and C. kefyr were found in three patients each (7.14%) and (iii) C. parapsilosis occurred in two patients (4.76%). During orthodontic treatment, the micro-organism count increased both in the saliva and on tooth surfaces. The results indicate that the prevalence of oral Candida spp. is high in young adults in south-eastern Turkey and that the Candida counts increase when braces are involved.

Candida in oral lichen planus patients undergoing topical steroid therapy

To determine the incidence, intensity, and species of Candida in the oral cavity of oral lichen planus (OLP) patients who were being treated with a topical steroid. The incidence and intensity of oral Candida carriage were assessed by salivary and imprint cultures. Cytological smears were used to investigate the presence of Candida spores and hyphae in the OLP lesions. Candida species were identified by a chlamydospore formation test and the API 20C system. The salivary cultures were positive in 76.7% of the OLP patients and 43.3% of the controls (P = .008), whereas the imprint cultures were positive in 76.7% of the OLP patients and 40% of the controls (P = .004). A high-level Candida count in saliva was more frequently found in the OLP patients than in the controls (73.9% vs. 38.5%; P = .004). The mean scores of Candida growth from imprint cultures were higher in OLP patients than in the controls (P = .002). The mean scores of Candida growth were also higher in OLP patients who were taking xerogenic or immunosuppressive drugs (P = .038) and in OLP denture wearers (P = .022). Spores and hyphae were detected in 83.3% of the OLP lesions. Candida albicans, the most frequently isolated yeast, was found in 76.7% OLP patients and 40% of the controls. The results of this study indicate that topical steroids induce Candida growth and the associated risk factors are age, medication use, and the wearing of dentures.