Treatment with probiotics in experimental oral colonization by Candida albicans in murine model (DBA/2)

The aim of this study is to evaluate the oral colonization by Candida albicans in experimental murine immunosuppressed DBA/2 and treatment with probiotic bacteria. To achieve these objectives, 152 DBA/2-immunosuppressed mice were orally inoculated with a suspension of C. albicans containing 10(8) viable yeast cells, the animals were treated with nystatin or with the probiotics (Lactobacillus acidophilus and Lactobacillus rhamnosus). Evaluations were performed by Candida count from oral mucosa swabbing. The oral mucosa colonization by C. albicans started at day 1 after inoculation, remained maximal from day 3 until day 7, and then decreased significantly. Probiotics reduced the C. albicans colonization significantly on the oral mucosa in comparison with the untreated animal group. In the group treated with L. rhamnosus, the reduction in yeast colonization was significantly higher compared with that of the group receiving nystatin. Immunosuppressed animal model DBA/2 is a relevant model for experimental Candida oral colonization, and the treatment with probiotics in this model may be an effective alternative to prevent it.     

Effects of salivary protein flow and indigenous microorganisms on initial colonization of Candida albicans in an in vivo model

ABSTRACT: BACKGROUND: Candida albicans is a dimorphic fungus that is part of the commensal microbial flora of the oral cavity. When the host immune defenses are impaired or when the normal microbial flora is disturbed, C. albicans triggers recurrent infections of the oral mucosa and tongue. Recently, we produced NOD/SCID.e2f1-/- mice that show hyposalivation, decrease of salivary protein flow, lack IgA and IgG in saliva, and have decreased NK cells. Our objective was to characterize C. albicans infection and biofilm formation in mice. METHODS: NOD/SCID.e2f1-/- mice were used as an animal model for C. albicans infection. C. albicans yeast and hyphal forms solutions were introduced in the oral cavity after disinfection by Chlorhexidine. RESULTS: The numbers of C. albicans colonized and decreased in a time-dependent manner in NOD/SCID.e2f1+/+ after inoculation. However, the colonization levels were higher in NOD/SCID.e2f1+/+ than NOD/SCID.e2f1-/- mice. In the mice fed 1% sucrose water before inoculation, C. albicans sample was highly contaminated by indigenous microorganisms in the oral cavity; and was not in the mice fed no sucrose water. The colonization of C. albicans was not influenced by the contamination of indigenous microorganisms. The hyphal form of C. albicans restricted the restoration of indigenous microorganisms. The decreased saliva in NOD/SCID.e2f1-/- did not increase the colonization of C. albicans in comparison to NOD/SCID.e2f1+/+ mice. We suggest that the receptor in saliva to C. albicans may not be sufficiently provided in the oral cavity of NOD/SCID.e2f1-/- mice. CONCLUSION: The saliva protein flow may be very important for C. albicans initial colonization, where the indigenous microorganisms do not affect colonization in the oral cavity.     

Oral colonization by Candida species in AIDS pediatric patients

The aim of this study was to assess the prevalence of factors associated with oral colonization by Candida spp. in pediatric patients with AIDS. The sample comprised of 117 children. Clinical status, medicines in use, and laboratory findings were obtained from hospital records; sociodemographic data were given by relatives. A dental examination assessed the prevalence of dental caries. The prevalence of oral colonization by Candida was 62%. Only seven children presented clinical manifestation of oral candidosis despite their high viral load index and low-for-age CD4 count. Candida colonization was directly associated with frequent use of antibiotics (prevalence ratio [PR] = 1.44), sulfa drugs (PR = 1.23), alteration in the oral mucosa (PR = 1.55), and untreated dental caries (PR = 1.93). It was inversely associated with the use of antiretroviral therapies (PR = 0.65). Candida albicans was the most frequently detected species (80%); phenotypic tests did not detect C. dubliniensis strains. This study observed a low prevalence of Candida-related oral lesions in these patients, which is compatible with the hypothesis that antiretroviral medicines may have contributed to reducing oral manifestations from Candida infection. The high prevalence of Candida colonization in HIV+/AIDS children with untreated dental caries reinforces the importance of oral health care in interdisciplinary health units that assist these patients.     

The influence of antifungal drugs on virulence properties of Candida albicans in patients with diabetes mellitus

OBJECTIVE: This study investigated the influence of nystatin and fluconazole on virulence properties of Candida albicans. STUDY DESIGN: A total of 108 diabetic patients participated in the study. Eighty-eight patients had clinical oral candidosis. Drug therapy was given at 6 hourly intervals for nystatin or daily with fluconazole for a maximum of 2 weeks. Adhesion of C albicans to buccal epithelial cells was determined by using an autologous adhesion assay prospectively over 6 months. Phospholipase production was estimated by using an agar plate method. The data analysis included a paired Student t test and calculation of correlation coefficients. RESULTS: Unlike nystatin, treatment with fluconazole reduced the ability of C albicans to colonize the buccal mucosa for up to 8 weeks after the treatment. Patients without clinical signs of oral candidosis had significantly fewer C albicans isolates producing phospholipase than did patients with oral candidosis. Treatment with fluconazole, but not nystatin, reduced the production of phospholipase from C albicans oral isolates in patients with diabetes mellitus. CONCLUSIONS: In addition to being antifungal, fluconazole alters phospholipase production, modifies buccal epithelial cells, and reduces adhesion of C albicans to human buccal epithelial cells for up to 8 weeks posttreatment in diabetic patients with oral candidosis.     

Low virulent oral Candida albicans strains isolated from smokers

It is widely accepted that tabagism is a predisposing factor to oral candidosis and cumulate data suggest that cigarette compounds may increase candidal virulence. To verify if enhanced virulence occurs in Candida albicans from chronic smokers, a cohort of 42 non-smokers and other of 58 smokers (all with excellent oral conditions and without signs of candidosis) were swabbed on tong dorsum and jugal mucosa. Results showed that oral candidal loads do not differ between smoker and non-smokers. Activities of secreted aspartyl-protease (Sap), phospholipase, chondroitinase, esterase-lipase, and haemolysin secretions were screened for thirty-two C. albicans isolates. There were detected significant increments in phospholipasic and chondroitinasic activities in isolates from non-smokers. For other virulence factors, no differences between both cohorts were achieved.     

Oral candidosis by Candida albicans in normal and xerostomic mice

The aim of this study was to analyze the effect of sialoadenectomy on the development of oral candidosis after one or four inoculations of Candida albicans. Initially, a suspension containing 10(8) cells/ml of C. albicans ATCC 36801 was prepared. Seventy-eight sialoadenectomized mice and a similar amount of mice with normal salivary flow received a single inoculation of C. albicans suspension. Another group with a similar number of mice received 4 inoculations. The control group consisted of 6 sialoadenectomized mice and 6 mice with normal salivary flow that were not inoculated with C. albicans. Candidosis development was studied histologically in the tongue of the animals 1, 2, 3, 5, and 8 days after inoculation and at 15-day intervals up to 165 days. According to the results obtained, it could be concluded that sialoadenectomy and a higher frequency of yeast inoculation influenced the presence and extension of candidosis lesions.     

Role of thermal trauma in experimental oral mucosal Candida infections in rats

A model of candidosis in experimental rats was used to study the role of trauma in the aetiology of oral mucosal infections caused by Candida albicans. Standardised thermal trauma was delivered to the dorsum of the tongue of Sprague-Dawley rats and experimental candidosis was induced. Histologically. the site of trauma was invaded by hyphae earlier and more extensively than in control animals, leading to the conclusion that trauma facilitated the establishment of the C. alhicana infections.     

Effects of an oral health program on the occurrence of oral candidosis in a long-term care facility

OBJECTIVES: The aim was to evaluate the effectiveness of a preventive oral health program on the prevalence of oral candidosis in 237 frail or dependent residents in a long-term care facility. Half of the residents were included in an experimental group which benefited from a preventive oral hygiene program including instruction of the carers and implementation of a recall program for professional oral hygiene care. METHODS: Intraoral examinations and yeast cultures from the oral mucosa and the fitting denture surface were carried out at baseline and 18 months later. The outgrowth of yeast was estimated on Oricult-N dip slides using the scale: no growth; 1-20 colonies; 21-100 colonies; >100 colonies. RESULTS: At baseline (n = 237) and at 18 months (n = 159) the experimental and the control groups were similar with regard to the residents' distribution by age, sex, dental and prosthetic status and prevalence of denture stomatitis. The 78 residents lost had the same baseline characteristics as the survivors, except for being older. In the experimental group the severity of the inflammation of the palate decreased (P = 0.005) as well as the prevalence of glossitis (P = 0.005). At baseline high yeast scores from the mucosa (>20) were observed in about 50% of the residents in the experimental as well as the control group. At 18 months this figure was 23.4% for the experimental and 48.7% for the control group (P = 0.001). There was also a reduction of the number of residents with positive cultures and the denture yeast scores at 18 months in the experimental group (P = 0.05). CONCLUSIONS: This study has shown that the preventive program was effective in reducing the colonization of the oral mucosa and dentures by Candida and thereby improving the health of the oral mucosa.     

Differential invasion of Candida albicans isolates in an in vitro model of oral candidosis

The study assessed the ability of Candida albicans isolates to invade an in vitro oral tissue model. The extent and pattern of isolate invasion was then correlated with the infection origin of the isolate to identify characteristics that may be restricted to specific forms of oral infection, particularly chronic hyperplastic candidosis (CHC). Reconstituted human oral epithelium was infected with C. albicans isolated from normal oral mucosa (n = 4), CHC (n = 7), non-CHC oral candidoses (n = 4) and squamous cell carcinoma (SCC; n = 4). After infection for 24 h, histological analysis revealed yeast adhesion, hyphal extension, and invasion of the epithelium. Differential patterns of invasion were evident and, whilst consistent for a given isolate, did not relate to the infection origin of the isolate. Two principal patterns of invasion were evident and described as either a 'localised' or a 'uniform' distribution of invading hyphae. Several isolates also exhibited superficial infection with limited hyphal invasion. In conclusion, the use of the in vitro tissue model allowed the assessment of the invasive capabilities of isolates of C. albicans. However, the apparent differences in invasive characteristics did not appear to be related to the clinical origin of isolates.     

In vitro antifungal resistance of oral Candida albicans strains in non-AIDS Patients

Some cases of oral candidosis are refractory to antifungal treatment. This might be related to development of resistant Candida strains, but susceptibility testing is not standardized and not routinely available, and information related to this problem is scarce in non-AIDS patients. In this study, the in vitro antifungal resistance of oral Candida albicans strains was evaluated. The strains were obtained from a cohort of 72 HIV-negative patients with oral yeast carriage and clinical complaint. Laboratory identification revealed C. albicans in 93% of cases. None of these oral C. albicans isolates showed in vitro resistance to polyenes, but they showed varying resistance levels to fluorocytosine and azoles. This study confirms the usefulness of standardizing susceptibility testing so that it could be routinely available and of realizing a mycological diagnosis including an antifungigram when oral candidosis is suspected, whenever antifungal treatment with azoles is planned.     

Adhesion of oral C. albicans to human buccal epithelial cells following limited exposure to antifungal agents

The major aetiologic agent of oral candidosis is C. albicans , and adhesion to oral mucosal surfaces is considered a vital prerequisite for successful colonisation and subsequent infection by this agent. Although many antimycotics are available for the treatment of oral candidosis, the diluent effect of saliva and the cleansing action of the oral musculature often tend to reduce the availability of the agents below that of the effective therapeutic concentration. Therefore, the yeasts undergo only a limited exposure to the antifungals during therapy. Hence, the main aim of the present study was to determine the in vitro adhesion of ten isolates of oral C. albicans to buccal epithelial cells (BEC) following a short exposure to sublethal concentrations of four antifungal agents. The yeasts were exposed to sublethal concentrations of nystatin (X6 MIC), 5-fluorocytosine (X8 MIC), ketoconazole (X4 MIC) and fluconazole (X4 MIC) for a period of 1 h. Following subsequent removal of the drug, the adhesion of these isolates to BEC was assessed by a previously described adhesion assay. The mean percentage reductions of candidal adhesion to BEC following exposure to sublethal concentrations of nystatin, 5-fluorocytosine, ketoconazole and fluconazole were 72.88%, 16.52%, 40.16% and 24.36%, respectively. Ultrastructural studies revealed that short exposure to nystatin and the azoles (but not 5-fluorocytosine) resulted in aberrant cellular features. These findings indicate that subtherapeutic levels of antifungals may modulate candiadal colonisation of the oral mucosa and thereby suppress the invasive potential of the pathogen.     

Histopathology, immunology, and serology of oral yeast infections. Diagnosis of oral candidosis

For diagnostic purposes it is normally not important to obtain a biopsy specimen, since an oral smear from the lesion will yield blastospores and pseudohyphae in abundance. However, in lesions that respond poorly to antimycotic treatment a biopsy should be carried out to detect possible malignant changes in the epithelium. Assessment of cell-mediated immunity against Candida albicans and other antigens may be important in patients with severe chronic candidosis to assess the degree of immunocompetence and prognosis. Usually, patients with oral candidosis show only moderately elevated antibody titers in serum and saliva against C. albicans, and serologic tests are normally not a diagnostic tool for oral candidosis. However, such tests may be a prognostic instrument in patients with severe oral candidosis who respond poorly to antimycotic therapy.     

白念珠菌口腔黏膜感染小鼠模型的建立及评估

［摘要］ 目的 建立白念珠菌口腔黏膜感染ICR小鼠模型,动态观察口腔黏膜及相应的全身感染情况,并对变化情况进行初步分析。方法 将白念珠菌接种于免疫功能低下小鼠口腔,采用肉眼观察口腔舌背病损改变、口腔内白念珠菌菌量检测、组织病理学等方法评估口腔内黏膜感染情况,检测体重、载菌量（肾、肝、下降结肠内粪便）评估全身感染情况。观察1周,并记录数据。空白对照组为接种生理盐水的免疫功能低下组。结果 ①小鼠接种白念珠菌后第1天口腔白念珠菌菌量较低,随后迅速增长,3~7 d内趋于稳定,稳定于106~107CFU/mL。同时口腔舌背病损也出现类似趋势,第1天未见明显伪膜,3~7 d内可见舌背伪膜存在。②病理切片PAS染色显示接种后3~5 d内白念珠菌形成菌丝侵入并破坏上皮,到接种第7天时,黏膜上皮多见酵母细胞。③小鼠接种白念珠菌后体重逐渐下降。粪便载菌量逐渐上升,第5天达到最大,但肾、肝无白念珠菌感染。空白组未见白念珠菌感染。结论 通过在ICR小鼠口腔内接种白念珠菌可以建立白念珠菌口腔黏膜感染动物模型。接种后白念珠菌感染程度在1周内存在变化。动物实验应根据感染状况选择合适的研究时段。     

口腔念珠菌病患者口内菌株的检出和药敏性观察

目的通过对健康人和口腔念珠菌病患者口内假丝酵母菌（即念珠菌）株的检测和药物敏感性试验,探讨假丝酵母菌的种类及药敏性,并结合制霉菌素局部疗效的观察,初步探讨最小抑菌浓度（MIC）值与临床疗效的关系,为临床用药提供参考。方法选择61例口腔念珠菌病患者为试验组,43例健康自愿者为对照组,含漱法收集口腔假丝酵母菌标本,采用CHROMagar假丝酵母菌显色培养基对其进行分离鉴定,然后采用NCCLSM27- A微量稀释法测定假丝酵母菌分离株对制霉菌素、酮康唑和氟康唑的MIC值。试验组中选择31例进行制霉菌素治疗,1周后观察临床疗效,并与患者的MIC值作比较。结果①试验组和对照组假丝酵母菌检出率分别为78.69%和30.23%,其中白色假丝酵母菌分别占80.70%和92.31%。②白色假丝酵母菌对氟康唑和酮康唑的MIC值均数间无统计学差异（P>0.05）,但唑类药物的MIC值小于制霉菌素。③白色假丝酵母菌对氟康唑、酮康唑和制霉菌素的敏感率分别为95.65%、80.43%和89.13%,少数菌株存在耐药现象。④制霉菌素局部治疗口腔念珠菌病有效率为87.10%,存在少数MIC值与临床疗效结果不一的病例。结论目前口腔假丝酵母菌感染患者口内菌株的耐药现象并不突出,白色假丝酵母菌对氟康唑、酮康唑、制霉菌素的敏感率均较高;酮康唑和氟康唑MIC值较小,提示临床上用制霉菌素治疗疗效欠佳时可换用唑类药物。MIC值与临床疗效存在一定相关性,但MIC值高低与临床疗效并非完全一致。     

Epithelial mitotic activity during the induction of palatal candidosis in the Wistar rat

Palatal candidosis was produced in 15 Wistar rats by fitting them with an acrylic appliance that covered the palatal mucosa and simultaneously inoculating this site with Candida albicans 3091 (serotype A). A further 15 rats were fitted with the appliance only. Five animals in each group were killed at 1, 2 and 4 weeks, 4 X 5 h after being injected with vinblastine sulphate, as were 5 normal control animals at the start of the experiment. Palatal mucosa was dissected free, fixed, sectioned and stained prior to counting the number of arrested mitotic figures in the basal epithelial layer and measuring the mean thickness of epithelium. The results were expressed as the number of mitotic figures per 1000 basal cells, per unit length of basement membrane and per square millimetre of epithelial surface. After an initial reduction in thickness, the palatal epithelium in both experimental groups became thicker than that of normal control animals, more markedly so in the animals infected with Candida albicans. Similar patterns of mitotic activity were found regardless of the reference unit used as a basis for the calculations. An initial decrease in both experimental groups was followed by a sharp and significant rise, again being more marked in the animals infected with Candida albicans.     

2型糖尿病患者罹患口腔假丝酵母菌感染危险因素的Logistic回归分析

目的通过多因素分析,筛选出与2型糖尿病患者伴发口腔假丝酵母菌感染密切相关的指标,建立预测方程,分析2型糖尿病患者口腔假丝酵母菌感染的危险因素。方法选择140例2型糖尿病患者,记录性别,年龄,病程,吸烟史,空腹血糖值及系统并发症（包括肾病、神经病变和高血压）;并对患者进行口腔检查,记录口腔卫生状况、口腔黏膜情况及义齿修复情况。运用标准含漱浓缩法检测患者口腔假丝酵母菌的检出率和负载量,并采用CHROM agar显色培养基进行初步生物分型。应用Logistic回归分析方法研究2型糖尿病患者口腔假丝酵母菌感染与上述11项临床指标之间的关系。结果140例2型糖尿病患者中有69例检出口腔假丝酵母菌,检出率为49.3%,检出的假丝酵母菌菌种以白假丝酵母菌为主。以上述11项临床指标作为自变量,口腔假丝酵母菌感染发生与否作为因变量,进行Logistic回归分析,建立Logistic回归方程,方程的总判断率为82.1%。经回归分析,空腹血糖值、口腔卫生状况和黏膜干燥是2型糖尿病患者伴发口腔假丝酵母菌感染的危险因素。结论空腹血糖值、口腔卫生状况、黏膜干燥是2型糖尿病患者伴发口腔假丝酵母菌感染的危险因素;通过回归方程得出的概率值可为2型糖尿病患者口腔假丝酵母菌感染的预测及口腔护理保健提供参考。     

Epithelial mitotic activity during the induction of palatal candidosis in the Wistar rat

Palatal candidosis was produced in 15 Wistar rats by fitting them with an acrylic appliance that covered the palatal mucosa and simultaneously inoculating this site with Candida albicans 3091 (serotype A). A further 15 rats were fitted with the appliance only. Five animals in each group were killed at 1, 2 and 4 weeks, 4·5h after being injected with vinblastine sulphate, as were 5 normal control animals at the start of the experiment. Palatal mucosa was dissected free, fixed, sectioned and stained prior to counting the number of arrested mitotic figures in the basal epithelial layer and measuring the mean thickness of epithelium. The results were expressed as the number of mitotic figures per 1000 basal cells, per unit length of basement membrane and per square millimetre of epithelial surface. After an initial reduction in thickness, the palatal epithelium in both experimental groups became thicker than that of normal control animals, more markedly so in the animals infected with Candida albicans. Similar patterns of mitotic activity were found regardless of the reference unit used as a basis for the calculations. An initial decrease in both experimental groups was followed by a sharp and significant rise, again being more marked in the animals infected with Candida albicans .     

Oral candidosis in non-Hodgkin's lymphoma: a case report

Though oral candidosis is an opportunistic fungal infection that commonly affects immunocompromised patients, little is known of its occurrence as a complication of Non-Hodgkin's lymphoma. This paper reports a case of oral candidosis in a 20-year-old Indonesian woman with this lymphoproliferative disease. She presented with acute pseudomembranous candidosis on the dorsum and lateral borders of the tongue, bilateral angular cheilitis and cheilocandidosis. The latter is a rare clinical variant of oral candidosis, and the lesions affecting the vermilion borders presented as an admixture of superficial erosions, ulcers and white plaques. Clinical findings were confirmed with oral smears and swabs that demonstrated the presence of hyphae, pseudohyphae and blastospores, and colonies identified as Candida albicans. A culture from a saline rinse was also positive for multiple candidal colonies. Lip and oral lesions were managed with Nystatin. The lesions regressed with subsequent crusting on the lips, and overall reduction in oral thrush. As Non-Hodgkin's lymphoma is a neoplastic disease that produces a chronic immunosuppressive state, management of its oral complications, including those due to oral candidosis, is considered a long-term indication.     

Expression of interleukin-8 and its receptor IL-8RA in chronic hyperplastic candidosis

INTRODUCTION: Neutrophils are the main opponents of Candida albicans in chronic hyperplastic candidosis. They migrate from the circulation to the epithelium where they form microabscesses. We therefore hypothesized that the neutrophil chemokine interleukin-8 (IL-8) might play a role in the neutrophil-Candida interaction. METHODS: Biopsies from patients with chronic hyperplastic candidosis (n = 10) were stained using the avidin-biotin-peroxidase complex protocol for IL-8 and IL-8 receptor A and were compared to healthy control mucosa (n = 3). A set of C. albicans agar sections was similarly analysed. RESULTS: In chronic hyperplastic candidosis lesions IL-8 was strongly expressed in both vascular endothelium and mucosal epithelium. Many resident and immigrant inflammatory cells, including intraepithelial neutrophils, were IL-8 receptor A positive. In addition, IL-8 (or an analogue) was found in the candidal mother cell in chronic hyperplastic candidosis and in agar, whereas the tips of the hyphae expressed IL-8 receptor A (or an analogue). CONCLUSION: IL-8 may play a role in the recruitment of neutrophils from the vascular compartment to the epithelial microabscesses. C. albicans may have developed an ability to sense IL-8. The IL-8 ligand-receptor interaction may help to direct the growth of the IL-8-receptor-containing tips of the hyphae away from the IL-8-producing candidal cell body (a centrifugal growth pattern to facilitate host tissue penetration). Later, this ability might help to keep the vulnerable hyphal tips away from areas with high concentrations of host IL-8 and candidacidal neutrophils. We suggest that this phenomenon, in contrast to chemotropism, is named chemophobia.