Oral distribution of Candida species and presence of oral lesions in Brazilian leprosy patients under multidrug therapy

Objective:  The aim of this study was to evaluate the prevalence of Candida spp. and presence of oral lesions in Brazilian leprosy patients under multidrug therapy (MDT).
Methods:  Thirty-eight individuals (18 males and 20 females, median age 53 years) clinically and microbiologically diagnosed as leprosy (lepromatous variant), and under MDT for at least 45 days were studied. The control group constituted by 38 healthy individuals (median age 53.5), matched to the test group in relation to age, gender and oral conditions. Oral rinses were collected and the Candida identification was performed by phenotypic tests. The existence of Candida dubliniensis among the isolates was analyzed using a validated multiplex PCR assay. Twenty-nine leprosy patients were examined intra-orally for the presence of lesions. Data were analyzed by z- and Mann–Whitney tests (α = 5%).
Results:  Yeast carriage rate between leprosy patients (65.8%) and controls (47.4%) was similar ( P  = 0.099), and no significant difference between yeast counts was observed ( P  = 0.1004). Candida albicans was the most frequently isolated species in both groups. In the leprosy group, Candida tropicalis and Candida parapsilosis were also identified. In the control group, we additionally identified Candida tropicalis , Candida glabrata and Candida kefyr. Candida dubliniensis was not detected. No leprosy-related oral lesion was registered.
Conclusion:  Within the limits of the study, we concluded that Brazilian leprosy patients under MDT showed similar levels of carriage and Candida species distribution in relation to the controls.     

Sjögren's syndrome sufferers have increased oral yeast levels despite regular dental care

Aim:  To investigate the prevalence and quantity of oral yeasts and their association with oral candidiasis in Sjögren's syndrome (SS) patients receiving regular dental care.
Materials and methods:  Yeasts in oral rinse and full-mouth supra-gingival plaque samples from 25 primary SS, 27 secondary SS and 29 control subjects were selectively cultured. All yeasts except single-species isolates were genotyped using pulsed field gel electrophoresis (PFGE).
Results:  Ten (19%) SS sufferers had symptomless candidiasis. SS subjects had a higher prevalence (73% vs 7%) and quantity of yeasts than controls in both oral rinse and plaque samples ( P  < 0.05). The prevalence of yeasts in plaque was associated with candidiasis regardless of denture wearing ( P  ≤ 0.04). Candida albicans was the predominant yeast isolated. PFGE showed 20 (66% of total) C. albicans isolate pairs, i.e. C. albicans species isolated from plaque and oral rinse samples of the same individual, were of closely related genetic clonal types ( P  < 0.01).
Conclusions:  Despite effective oral hygiene, more SS subjects than controls had detectable levels of oral yeasts and their presence in supra-gingival plaque was associated with candidiasis. Candida albicans colonized supra-gingival biofilm even in well-maintained SS individuals, posing a challenge to the control of oral candidiasis.     

Mixed Candida albicans and Candida glabrata populations associated with the pathogenesis of denture stomatitis

Introduction:  Oral yeasts are an important component of the resident microbial ecology of the oral cavity, but they are also associated with various forms of oral candidosis, such as denture stomatitis. Although Candida albicans is the predominant oral fungal pathogen, other species may also play an integral role in pathogenesis. The aim of this study was to examine the mycological ecology in patients with denture stomatitis, using an improved sampling technique, to determine whether species diversity and species quantity were related to oral pathology.
Methods:  Thirty-seven patients attending the Glasgow Dental Hospital were enrolled in this study following informed consent. A full clinical history was obtained, including details of their oral hygiene practices and the levels of erythema based on Newton's classification scale. Oral rinse, denture sonicate, and swab samples were taken, which were processed for quantitative and qualitative analysis of oral yeasts.
Results:  The proportion of patients with no inflammation or Newton's Types I, II, and III were 31, 33, 25, and 14%, respectively. Denture sonication was a superior sampling procedure, with statistically greater quantities of yeasts isolated using this methodology ( P  < 0.01). The predominant oral yeasts isolated were C. albicans (75%) and Candida glabrata (30%), which were isolated in higher proportions in patients with the highest grades of inflammation (100 and 80%), and in combination from 80% of these patients.
Conclusions:  This study has demonstrated that mixed C. albicans and C. glabrata biofilms may play an important role in the pathogenesis associated with severe inflammation in denture wearers.     

Prevalence of oral Candida species in leprosy patients from Cambodia and Thailand

BACKGROUND: Leprosy is a chronic bacterial infection which may lead to significant orofacial morbidity. However, reports on the oral mycotic flora of leprosy patients are rare. The aim of the current study was to explore the oral yeast carriage in two groups of leprosy patients. METHODS: 40 Cambodian (seven men, 33 women) and 48 Thai (14 men, 34 women) leprosy patients from Leprosy Rehabilitation Centre Khien Kleang, Phnom Penh, Cambodia and McKean Rehabilitation Center, Chiangmai, Thailand were randomly selected and their demographic data and clinical history were recorded. Tongue and palatal swabs of each patient were collected using sterile Fungi-Quick swabs (Hain Diagnostika, Nehren, Germany) and they were cultured aerobically on Sabouraud's dextrose agar and CHROMAgar (CHROMagar, Paris, France). Yeast were identified by germ tube, chlamydospore production, and assimilation tests (API 20C AUX, Bio-Merieux, Marcy l'Etoile, France) and reconfirmed using APILAB Plus system (Bio-Merieux). RESULTS: Two groups (Cambodian and Thai) had median age of 35 and 64 years. They had been with leprosy for median durations of 17.7 and 38.9 years (P<0.05), respectively. Overall yeast carriage in two cohorts were 80% and 93.75%. Candida albicans had highest carriage rate in either group (65.6%, 44.4%). Candida krusei and C. glabrata existed as second-line colonizers after C. albicans. Candida glabrata carriage was significantly higher in Thai patients (P<0.05). Multispecies carriage was seen in three Cambodian (9.4%) and five Thai (11.5%) patients. CONCLUSIONS: This study indicates high oral yeast carriage in leprosy patients. Candida albicans remains predominant while C. krusei and C. glabrata are second-line oral colonizers. Co-inhabitation of multiple yeast species is also noted in these patients' oral mycotic flora.     

Oral yeast carriage in patients with advanced cancer

The aim of this study was to investigate oral yeast carriage amongst patients with advanced cancer. Oral rinse samples were obtained from 120 subjects. Yeasts were isolated using Sabouraud's dextrose agar and CHROMagar Candida, and were identified using a combination of the API 20 C AUX yeast identification system, species-specific PCR and 26S rDNA gene sequencing. Oral yeast carriage was present in 66% of subjects. The frequency of isolation of individual species was: Candida albicans, 46%; Candida glabrata, 18%; Candida dubliniensis, 5%; others, < 5%. The increasing isolation of non-Candida albicans species is clinically important, since these species are often more resistant to antifungal drugs. Oral yeast carriage was associated with denture wearing (P = 0.006), and low stimulated whole salivary flow rate (P = 0.009). Identification of these risk factors offers new strategies for the prevention of oral candidosis in this group of patients.     

Phenotypic and genotypic characterization of oral yeasts from Finland and the United States

A total of 4–22 isolates of oral yeasts per subjects from 48 yeast-positive Finnish and American subjects (25 females and 23 males) were phenotyped and genotyped to determine the frequency of simultaneous oral carriage of multiple yeast taxa. An oral sample from either periodontal pockets, oral mucosa or saliva was obtained. All subjects yielded Candida albicans and 3 subjects an additional yeast species ( Candida krusei, Candida glabrata or Saccharomyces cerevisiae ). The API 20C Aux kit distinguished 9 different carbohydrate assimilation profiles among the C. albicans isolates. Thirty-eight of 46 C. albicans biotype I isolates were categorized in a single numerical profile. PCR analysis, using a random primer OPA-03 and a repetitive primer (GACA)₄, detected 2 major genotypic groups among the C. albicans isolates; 44 subjects showing isolates with a "typical" PCR-profile and 4 subjects isolates with an "atypical" PCR-profile. The "atypical" PCR-profile was similar to that of Candida dubliniensis. All C. albicans isolates assimilated xylose, except 5, including the 4 with an "atypical" PCR-profile. No difference was found in distribution of oral yeast species, and of C. albicans phenotypes and genotypes between Finnish and American subjects. The present PCR method may offer a rapid and easy means of distinguishing oral Candida species.     

Human laminin-332 degradation by Candida proteinases

Background:  Human laminin-332 (Lm-332) degradation by 12 Candida strains and effects of synthetic proteinase inhibitors [Ilomastat (ILM), EDTA, chemically modified tetracycline-3(CMT-3), CMT-308, synthetic peptide CTT-2, and Pefabloc] were studied.
Materials and methods:  Laminin-332 was incubated with sonicated cell fractions and 10 times concentrated cell-free fractions of reference and clinical strains of C. albicans, C. dubliniensis , C. guilliermondii , C. glabrata, C. krusei , and C. tropicalis . Proteolysis, pH effects, and inhibitors were analyzed by fluorography and zymography.
Results:  Cell fractions of all species except C. guilliermondii and cell-free fractions of C. albicans , and C. dubliniensis showed 20–70 kDa gelatinases at pH 5.0 and 6.0. At pH 7.6, C. glabrata , C. krusei , and C. tropicalis cell fractions and C. tropicalis cell-free fractions showed 55–70 kDa gelatinases. CMT-3, CMT-308, and CTT-2 inhibited Candida gelatinases slightly better than Pefabloc, ILM, and EDTA. No Candida fractions degraded Lm-332 at pH 7.6, but at pH 5.0, 100 kDa bands were generated by cell fractions of C. dubliniensis and C. tropicalis ; C. albicans and C. glabrata clinical strains; and C. guilliermondii reference strain. C. krusei reference strain yielded three 100–130 kDa bands. C. albicans , C. dubliniensis , and C. tropicalis reference and clinical strain's cell-free fractions generated 100 kDa band .
Conclusions:  Laminin-332 degradation is pH-dependent and differences exist between studied Candida strains. Lm-332 degradation can exert functional disturbances on basement membrane integrity, possibly aiding Candida cell invasion into tissues. Certain synthetic matrix metalloproteinase inhibitors (CMTs, CTT) can inhibit Candida proteinases and may be therapeutically useful in future.     

Oral candidiasis: a comparison between conventional methods and multiplex polymerase chain reaction for species identification

Background/aim:  Oral candidiasis is the most common fungal infection in dental practice, and is caused by yeasts that are normally present in the endogenous flora.
Methods:  To evaluate a rapid diagnostic method for identification of Candida oral isolates, a multiplex polymerase chain reaction (PCR) was carried out on colonies and on oral rinse solutions from 95 subjects with suspected oral candidiasis and results were compared with those from seven commonly used phenotypic identification systems.
Results:  Between four and nine species were characterized in the samples by the phenotypic methods. PCR identified the same species in 60 (74%) samples from both colony and oral rinse solutions. Statistical analysis, carried out only for the three most frequently isolated species ( Candida albicans , Candida    glabrata , and Candida tropicalis ), showed good concordance in the comparison of multiplex PCR with API 20C AUX and with the Rapid Yeast Identification Panel; conversely, significant differences were registered in the comparison between the molecular method and other phenotypic systems, including four chromogenic media and the automated system Vitek2.
Discussion:  Multiplex PCR was rapid and effective in the identification of Candida species and allowed the detection of more than one species in the same sample.     

HIV感染者口腔念珠菌负荷及生物型研究

目的调查人类免疫缺陷病毒（human immunodeficiency virus，HIV）感染者口腔中念珠菌负荷状况、生物分型及与口腔念珠菌病临床表现的关系。方法采取漱口法对64例HIV感染者和42名健康对照者进行口腔念珠菌的定量分离培养，并综合利用革兰染色、厚壁孢子生成实验、CHROMagar显色培养和API 20C AUX酵母菌鉴定系统对分离株进行生物型鉴定。结果64例HIV感染者中，52例中可分离出念珠菌74株，阳性分离率为81．3％，而42名健康对照者口腔念珠菌阳性分离率仅为16．7％（P〈0．001）。通过对74株念珠菌的生物型进行鉴定，发现有39株白色念珠菌，15株热带念珠菌及其他6个生物型20株。健康对照组中，分离出5株白色念珠菌和其他裂2株。结论HIV感染者口腔念珠菌感染率明显增加，其口腔念珠菌的检出率和负荷量亦明显增加，白色念珠菌和热带念珠菌为其主要分离菌；与健康对照组相比，HIV感染者的口腔念珠菌分离株生物类型旱现多样化。     

Gene targeting demonstrates that inducible nitric oxide synthase is not essential for resistance to oral candidiasis in mice, or for killing of Candida albicans by macrophages in vitro

Introduction:  Oral candidiasis is caused by opportunistic infections with the yeast Candida albicans . Previous studies have demonstrated important roles for innate immunity and T helper type 1-mediated inflammatory reactions in recovery from infection, with macrophages and neutrophils as key effector cells. Both effector cell types use the inducible isoform of nitric oxide synthase (iNOS) to generate candidacidal molecules, but it is not clear whether nitric oxide (NO) is an absolute requirement for candidacidal effector activity.
Methods:  In this study we directly investigated the role of iNOS-derived NO in resistance to murine experimental oral candidiasis, using iNOS knockout mice.
Results:  Knockout mice were no more susceptible to oral candidiasis than wild-type controls. Bone marrow-derived macrophages from the knockout mice killed C. albicans yeasts efficiently in vitro , and were still able to produce nitrites in an iNOS-independent manner, albeit less efficiently than wild-type controls. There were no significant differences in local mucosal production of interleukins 6, 12, 17A, or 23, interferon-γ, or transforming growth factor-β 24 h after oral challenge with C. albicans .
Conclusion:  These data suggest that iNOS-derived NO is not required for resistance to oral candidiasis in vivo , and that bone marrow-derived macrophages may have iNOS-independent means of generating reactive nitrogen species.     

Oral epithelium-Candida glabrata interactions in vitro

BACKGROUND: Oropharyngeal candidiasis is a common opportunistic infection and Candida glabrata is the second or third most frequently isolated species from oropharyngeal candidiasis lesions, after Candida albicans. The aim of this study was to study the cytokine-inducing and cell-damaging potential of C. glabrata in oral epithelial cells and compare this to C. albicans. METHODS: Oral epithelial cell lines and primary gingival epithelial cells were cocultured with C. glabrata strains GDH2269 and 94-11 or C. albicans strains SC5314 and ATCC28366. Supernatants were analysed for the presence of interleukin-1alpha (IL-1alpha), IL-8 and granulocyte-macrophage colony-stimulating factor (GM-CSF) by enzyme-linked immunosorbent assay. The cytotoxity of different strains was determined using the CytoTox-96 assay. RESULTS: Compared to C. albicans, C. glabrata induced different proinflammatory cytokine responses in oral epithelial cells; a high level of GM-CSF induction was only detected in C. glabrata-infected cells and not in C. albicans-infected cells, regardless of the origin of these cells (cell lines or primary cells) or the strain used. Like C. albicans, C. glabrata induced an IL-1alpha response by oral epithelial cells, but this response was both strain-dependent and epithelial cell origin-dependent. Unlike C. albicans, C. glabrata failed to induce a strong IL-8 response in any of the cell systems studied. Finally, in these studies C. glabrata showed lower cytotoxicity than C. albicans. CONCLUSIONS: C. glabrata is less cytotoxic than C. albicans and induces different proinflammatory cytokine responses in oral epithelial cells.     

Salivary secretion, mucin concentrations and candida carriage in HIV-infected patients

Objectives:  To test whether the submandibular/sublingual (SMSL) salivary secretion, mucin concentration and candida carriage status were altered in human immunodeficiency virus-positive (HIV+) patients.
Subjects and methods:  SMSL saliva collected from 48 HIV-infected and 31 HIV-negative men were analyzed for flow rates, total protein and mucin concentrations. Salivary cultures were performed for Candida assessment.
Results:  The salivary flow rate and protein secretion of the HIV+ patients was 37% and 32% less than that of the controls ( P  <   0.0001, P  =   0.0087). The mucin concentrations (MG1 and MG2) were higher in the HIV+ subjects compared with controls ( P  =   0.0186, P  =   0.0014); however, the mucin secretions were not different. The frequency of Candida -positive cultures was higher in the HIV+ subjects than in the controls (61.4% vs 24.1%, P  =   0.0018). In the HIV-infected group, the unstimulated SMSL flow rates were lower in Candida -positive than in Candida -negative patients ( P  =   0.0158).
Conclusion:  The salivary secretion of the SMSL glands was reduced in HIV infection. Although the mucin concentration increased in HIV+ subjects, mucin secretion was not altered. Highly active antiviral therapy had no effect on salivary function. We found an association between the level of candida carriage and salivary flow rate in HIV-infected patients.     

中老年患者口腔念珠菌携带情况的研究

目的研究口腔修复门诊戴用和不戴可摘义齿中老年患者口腔念珠菌携带情况及常见的念珠菌菌种,并分析相关因素。方法选择不戴可摘义齿患者54人(A组),戴上颌可摘义齿患者84人(B组),年轻学生51人作为对照组(C组)。采集唾液培养并初步鉴定菌种,分析相关因素。结果 A组念珠菌检出率为51.9%,白念珠菌占82.1%。B组念珠菌检出率为82.1%,白念珠菌占73.9%。C组念珠菌检出率为17.6%,白念珠菌占55.6%。A、B、C 3组间及每两组间的念珠菌检出率差异均有统计学意义(P≤0.01)。结论戴用可摘义齿的中老年患者口腔念珠菌检出率显著高于不戴义齿中老年患者;中老年患者口腔念珠菌检出率明显高于年轻对照组。白念珠菌仍是口腔中主要念珠菌种。     

Frequency, species and molecular characterization of oral Candida in hosts of different age in China

INTRODUCTION: Research indicates that host age is a determining factor in yeast carriage. From the neonatal period, humans go through several dentition periods, and the emergence and substitution of teeth and changes in living habits greatly change the environment of the oral cavity, and therefore influence colonization by oral commensal organisms, certainly including Candida spp. No previous study of Candida carriage by different age groups divided by dentition has been reported. This study supplies data on the geographical specificity of C. albicans genotypic subgroup distribution. METHODS: All test individuals came from a single geographical locale over a short period. Following mucosal swab sampling, CHROMagar Candida-yeast differential media were used to determine the frequency of carriage and species. All C. albicans strains were confirmed by PCR and PCR using primers reported to span a transposable intron region in the 25S rRNA gene was used to determine genotypic subgroups. RESULTS: The results demonstrate that for the tested population, the frequency of Candida species and the distribution of C. albicans genotypic subgroups varied with age group. With increasing age, the frequency of C. albicans decreases, non-C. albicans yeasts increases; Genotypic subgroup A is the dominating strain in the oral cavities of healthy young individuals. CONCLUSIONS: The influence of dentition substitution on oral yeast carriage was minor.     

Asymptomatic oral Candida albicans carriage in HIV-infection: frequency and predisposing factors

Many studies have focused on the epidemiology and pathogenesis of oral candidiasis in HIV infection. Little is known on the incidence and predisposing factors of asymptomatic oral Candida carriage in this setting, obviously an important issue in view of prophylaxis. To address this question. 261 consecutive HIV-infected individuals without clinical evidence of candidiasis were investigated. C. albicans was isolated from cultured oral cavity swabs of 63 subjects (24%). Colonization was significantly more frequent in IV drug users. CDC groups IV. and in subjects with lymphocytopenia. CD4+ cell depletion, or elevated beta-2 microglobulin. These data further suggest that oral candidiasis occurs in HIV infection as a result of C. albicans overgrowth and raise the question of primary antifungal prophylaxis in subjects with low CD4 counts and asymptomatic oral Candida carriage.     

Mycological and cytological examination of oral candidal carriage in diabetic patients and non-diabetic control subjects: thorough analysis of local aetiologic and systemic factors

In this study, 55 diabetic patients and 45 non-diabetic control subjects were examined to determine oral candidal carriage state. The influence of some local aetiologic and systemic factors such as: salivary flow rate and pH, heredity, alcohol drinking, smoking habits, antimicrobial therapy, wearing of denture, burning sensation, dry mouth, taste alteration and tooth brushing habit on candidal carriage rate were investigated. Imprint culture, cytological smears and biochemical tests were used. Oral carrier rate and density of Candida species were non-significantly higher in the diabetic patients than in the non-diabetic control subjects. This increase was confirmed cytologically too. In both groups, Candida albicans was found to be a predominant species on tongue dorsum. Cigarette and alcohol habits of men were higher while tooth brushing habit was less than in women in diabetic and control groups. Salivary flow rate and pH values of diabetic patients were significantly lower while serum glucose values were significantly higher than of non-diabetic controls. The rate of diabetic patients suffering from dry mouth and having diabetic heredity in the family were significantly higher than control subjects. The candidal colonization was higher and keratinization was lower while diabetic treatment tended from diet and oral antidiabetic towards insulin. The decrease in salivary pH, the increase in serum glucose and wearing denture were correlated with the increased rate and density of C. albicans in both groups. Keratinization was also accompanied with the increase in leucocytes. In diabetic group, positive correlations were found between antimicrobial therapy and C. glabrata carriage; the increase in leucocytes and C. albicans carriage; the increase in keratinization and alcohol habit; serum glucose and smoking habit; dry mouth complaint and antimicrobial therapy. There was a negative correlation between salivary flow rate and C. albicans carriage. In control group a positive correlation was found between antimicrobial therapy and keratinization.     

In vitro antifungal effect of amine fluoride-stannous fluoride combination on oral Candida species

OBJECTIVE: The combination of amine fluoride and stannous fluoride (AmF/SnF2) was, by chance, found to be antifungal in a clinical trial. This study investigated its effect on pathogenic Candida species with the hypothesis that the antifungal action on different species is variable. MATERIALS AND METHODS: Growth inhibition effect of Meridol mouth rinse which contains 250 ppm AmF/SnF2 was evaluated on 43 reference and clinical strains of Candida albicans, C. dubliniensis, C. glabrata, C. guilliermondii, C. krusei, C. parapsilosis, and C. tropicalis. Meridol base solution without AmF/SnF2 was used as a negative control. RESULTS: Undiluted Meridolmouth rinse killed most study strains within a few minutes. In ascending order, C. parapsilosis, C. tropicalis, C. albicans, C. glabrata, C. krusei and C. dubliniensis showed higher resistance against AmF/SnF2 than C. guilliermondii. CONCLUSION: AmF/SnF2 could be used as a potent adjunct to antifungal therapy for oral yeasts. Although different Candida species demonstrated variable sensitivity the most prevalent oral yeast C. albicans appeared sensitive to the AmF/SnF2 combination.     

The effects of orthodontic appliances on Candida in the human mouth

Background.  Candida is an opportunistic pathogen present in about 50–60% of the healthy human population, and becomes pathogenic when the host immune defence is undermined such as in HIV infection. Adhesion and colonization of the oral cavity by Candida albicans is an initial step in candidosis, and the presence of orthodontic and other oral appliances seems to alter the oral ecological environment, hence may tip the balance to favour the candidal presence.
Objective.  The purpose of this paper was to review the literature with specific attention to prevalence; intra-oral density of the candidal organisms; and Candida carriage status in orthodontic patients before, during, and after treatment.
Conclusions.  The limited amount of literature demonstrated that the density of Candida increases; the most common Candida species isolated in the orthodontic patients was C. albicans ; and that there seems to be a direct relationship between the presence of a removable appliance, Candida , and low salivary pH levels. No healthy patients developed Candida infection from the orthodontic appliances. However, there seems to be a trend that some non- Candida carriers converted to Candida carriers following the insertion of the appliances by unknown mechanism. This may indicate a more cautious approach when providing orthodontic treatments to immunocompromised children concerning the possible increased risk of candidal infection.     

Implantation of Candida albicans and other Candida species in the oral cavity of rats

The carriage of five Candida species in the mouths of normal and siaioadenectomised rats was determined for periods up to 30 days after inoculation into the oral cavity. In both test and control animals. Candida albicans was the species recovered in greatest quantities at all periods, followed by C. parapsilosis and C. tropicalis. In contrast. C. gullliermondii and C. krusei were isolatable only in small numbers and only from the 1st up to the 5th day; they were not present thereafter. Sialoadenectomy favoured oral colonisation only by C. albicans ( P <0.05) and did not influence the carriage of the other species.     

Betel quid-associated oral lesions and oral Candida species in a female Cambodian cohort

BACKGROUND: Betel quid chewing (BQC) is still prevalent among elderly Cambodian women and is associated with a wide variety of oral mucosal lesions. BQC has also been associated with a reduced rate of dental caries and changes in the oral microbiological flora. METHODS: Since no studies were available on the impact of BQC on the oral carriage of Candida species, in this study oral swabs (Fungiquick, Hain Diagnostika, Germany) were taken from the tongue and palate of 48 Cambodian women with BQC habit (study group) and 13 control subjects without BQC habit (control group) to determine the spectrum of Candida species in these two groups. In addition, we investigated lesions of the oral mucosa likely to be associated with BQC habit in both study and control groups. RESULTS: The median duration of BQC was 10 years (range 10 months-30 years). The following oral lesions were found in the study group: betel chewer's mucosa (85.4%), oral leukoplakia (8.3%), leukoedema (37.5%) and oral lichen planus (4.2%). Oral candidiasis was seen neither in BQ-chewers nor in controls. Candida spp. were found in 70.8% of the cases (controls 69.2%). Whilst C. albicans was isolated from 27.1% of the study cohort, C. tropicalis was the second most common isolate. One control case was colonised by C. dubliniensis--the first report of this organism from a Cambodian population. There was no significant difference in the candidal carriage rate or the Candida species isolated between the study and the control group. CONCLUSIONS: Mycological findings from the present study do not indicate that BQC has a significant effect on oral colonisation by Candida species.