Characterization of Candida parapsilosis infection of an in vitro reconstituted human oral epithelium

Oral candidosis is a common problem in immunocompromised patients, and whilst Candida albicans is regarded as the principal cause of infection, other non‐Candida albicans Candida (NCAC) species are increasingly being recognized as human pathogens. Relatively little is known about the virulence factors associated with NCAC species, and the aim of this study was to use a reconstituted human oral epithelium (RHOE) to examine epithelial infection withCandida parapsilosis. Strains originating from the oral and vaginal mucosa and from the urinary tract were all shown to colonize RHOE in a strain‐dependent manner. Strain differences were found in the colonizing morphology and in the extent of invasion of the RHOE. Low invasion of RHOE was detected for strains after 12 h, whereas extensive tissue damage was evident after 24 h when assessed using histological examination and lactate dehydrogenase activity determination. Tissue damage was reduced in the presence of pepstatin A, although C. parapsilosis invasion of the tissue was not inhibited. Real‐time polymerase chain reaction of secreted aspartyl proteinase (SAP) genes (SAPP1–3) showed that expression was strain dependent, with an increased expression generally occurring for Candida infecting RHOE compared with planktonic equivalents. In summary, C. parapsilosis was not highly invasive of RHOE but did induce significant tissue damage, which could relate to specific SAPgene expression.     

The impact of cigarette/tobacco smoking on oral candidosis: an overview

Smoking is associated with a variety of changes in the oral cavity. Cigarette smoke has effects on saliva, oral commensal bacteria and fungi, mainly Candida, which causes oral candidosis, the most common opportunistic fungal infection in man. How cigarette smoke affects oral Candida is still controversial. This brief overview is an attempt to address the clinical findings on the relationship between smoking and oral candidosis and possible mechanisms of pathogenicity.     

口腔黏膜病患者口腔念珠菌感染情况的分析

目的 分析了解口腔黏膜病患者感染白念珠菌的情况。方法 收集2019年就诊于口腔黏膜科并进行白念珠菌培养的2 289 例患者,收集其基本信息、临床资料及实验室检查情况。按年龄分组:0～16岁(1组,38例),17～29岁(2组,181例),30～39岁(3组,274例),40～49岁(4组,325例),50～59岁(5组,535例),60～69岁(6组,540例),70岁及以上(7组,396例)。结果 白念珠菌总感染率为 30.6%,且女性患者感染率高于男性(33.1% vs.25.1%,P<0.05)。随着年龄的增长,白念珠菌感染率总体是上升的,且第6、7组感染率明显高于第2、3、4、5组(P<0.05)。除了口腔念珠菌病本身,唇舌疾病及口腔斑纹类疾病中最容易检测出白念珠菌,且白念珠菌的阳性检出与唇舌疾病、干燥综合征、口腔斑纹类疾病等相关。在同时进行白念珠菌培养及真菌镜检且白念珠菌培养阳性的患者中,真菌镜检阳性为50例,阳性率为35.5%。对白念珠菌培养阳性患者进行制霉素片及2%～3%碳酸氢钠溶液的局部治疗,其药物有效率为81.36%。结论 口腔念珠菌病更容易发生于60岁以上老年女性;且与系统性疾病、口腔斑纹类疾病相关。制霉素片联合2%～3%碳酸氢钠溶液局部治疗口腔念珠菌病效果尚可。     

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.     

Expression of p53 in oral mucosal hyperplasia, dysplasia and squamous cell carcinoma

OBJECTIVE: To assess p53 expression in a range of oral mucosal lesions and to relate the results to the clinical outcome in patients with dysplastic oral mucosal lesions and oral squamous cell carcinomas (OSCC).
MATERIALS AND METHODS: Archival tissue was available for eight cases of normal oral mucosa, 50 cases of oral mucosal hyperplasia, 41 cases of oral mucosal dysplasia and 48 cases of OSCC. The monoclonal antibody DO-7, reactive to p53 protein, was applied to paraffin-embedded sections using microwave pretreatment and immu-nohistochemical techniques.
RESULTS: The results showed that normal oral mucosa did not express p53.Positive nuclear staining was found in 18/50 (36%) cases of hyperplasia, 35/41 (85%) cases of dysplasia and 45/48 (94%) cases of OSCC.None of the p53 negative dysplasias progressed, while 19% of p53 positive cases of dysplasia recurred following excision and 11% of the cases underwent neoplastic transformation. Five out of 10 (50%) cases of severe dysplasia which were p53 positive resolved.
CONCLUSION: The proportion of cases with positive p53 expression increased from hyperplasia to dysplasia to OSCC. These results may indicate an involvement of p53 in neoplastic transformation as well as in proliferative events although the presence or absence of p53 staining could not be used to predict the outcome of potentially malignant oral mucosal lesions.     

口腔黏膜白斑与念珠菌感染的临床分析

目的：研究口腔白斑念珠菌感染的临床和病理学特征。方法：利用过碘酸雪夫染色诊断念珠菌感染,回顾性分析448例白斑患者的活检组织中念珠菌感染率,并分析年龄、性别、白斑病损部位、白斑上皮异常增生等因素与感染的关系。结果：白斑组织中念珠菌的感染率14．1％。念珠菌性白斑比普通型白斑的上皮异常增生发生率更高（57．1％vs．33．8％）。回归分析显示＞60岁的老年患者、舌部白斑和上皮异常增生是念珠菌易感因素。结论：念珠菌感染和上皮异常增生密切相关。伴有上皮异常增生的舌部白斑的老年患者更易感染念珠菌。     

Histopathological changes in oral mucosa due to takhzeen al-qat: a study of 70 biopsies

BACKGROUND: Chewing qat leaves (takhzeen al-qat) is a common habit in East Africa and Yemen. It has been reported to cause different systemic effects. At the oral mucosa, it causes clinical changes that appear as white lesions. The aim of this paper was to study the histopathological changes in the oral mucosa related to takhzeen al-qat. METHOD: Seventy biopsies were studied. Biopsies were divided into three groups: (G1) Forty biopsies were taken from the oral mucosa of the chewing side. (G2) Twenty biopsies were taken from the oral mucosa of the opposite side and (G3) 10 biopsies were taken from the oral mucosa of non-chewing volunteers. All biopsies were conventionally prepared, paraffin embedded and histopathological protocol was followed for each case to study the histopathological changes. RESULTS: Acanthosis appeared in 97.5% (G1) and 50% (G2), parakeratosis in 45% (G1) and 0% (G2), orthokeratosis in 25% (G1) and 10% (G2), abnormal rete ridges in 97.5% (G1) and 25% (G2), intracellular edema in 80% (G1) and 65% (G2), inflammatory infiltration in the subjacent connective tissue of 55% (G1) and 5% (G2), increased amount of collagenous fibers in 47.5% (G1) and 0% (G2), and mild epithelial dysplasia in 25% (G1) and 0% (G2). Biopsies taken from G3 showed no histopathological changes except one case with intracellular edema. Differences were statistically significant. CONCLUSION: Takhzeen al-qat caused histopathological changes in the oral mucosa at the side of chewing; however, these changes were innocuous and without any evidence of malignancy.     

Observer variability in the histologic assessment of oral premalignant lesions

Histopathologic examination of oral leukoplakias has a major impact on the assessment of prognosis and treatment planning. We investigated the extent of agreement in grading epithelial dysplasia between pathologists with the same or different educational backgrounds. Two general pathologists and two oral pathologists were each given 100 sections of oral leukoplakia to grade from no dysplasia to carcinoma in-situ. The interobserver agreement rates were in the range of 49% to 69%. The calculated kappa values were in the range of 27% to 45%), showing poor to moderate agreement between the pathologists. When comparing the kappa values between the two pairs of pathologists with the same education, these values did not diverge from the general level of kappa values, indicating that the interobserver variability was due to individual differences rather than to educational background.     

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.     

A retrospective study on the microbiology in patients with oral complaints and oral mucosal lesions

Objective:  The aim of this study was to microbiologically analyze oral mucosal samples collected during 2 years from patients with oral mucosal complaints.
Materials and methods:  Mucosal scraping samples were taken from 297 patients and semiquantified by culture for detection of opportunistic microorganisms e.g. Staphylococcus aureus , enterococci, aerobic Gram-negative bacilli (AGNB) and yeasts. Antibiotic susceptibility test was performed.
Results:  Altogether 297 patients were sampled (mean age 56.8 ± 20.7). Among the 110 patients with known medical condition, 48 were systemically immunocompromised, 35 had systemic diseases, and 27 had only local oral complaints. Opportunists in moderate growth or more were present commonly in all three groups and most frequent in the immunocompromised patients (66.7%). Candida species were the most frequent opportunist (68.8%), however, their level was low and combinations with bacterial opportunists were common (39.6%). All bacterial opportunists tested were antibiotic multiresistant. Follow-up samples were collected in 23 cases out of which seven showed still presence of opportunists in heavy growth despite repeated treatment with ciprofloxacin.
Conclusions:  This study showed a frequent presence of bacterial and fungal opportunists in patients with oral mucosal complaints, which were most common in immunocompromised individuals, however, also frequent in patients with local oral complaints only. Systematic evaluation of different treatment strategies is needed.     

Human papillomavirus frequency in oral epithelial lesions

BACKGROUND: Oral human papillomavirus (HPV) prevalence varies according to geographical occurrence, the type of lesion, and the method of diagnosis. The polymerase chain reaction method (PCR) appears to be more sensitive and can be easily applicable to epidemiologic studies. OBJECTIVES: To determine the frequency of HPV and its genotypes in oral lesions among patients attending a reference clinic of a university hospital. METHODS: PCR was performed to identify HPV DNA from samples of oral epithelial lesions in 80 patients. For HPV DNA amplification, MY09/MY11 consensus primers were used and specific genotypes were identified through restriction fragment of length polymorphism (RFLP) pattern. RESULTS: HPV DNA was present in 11.3% of patients, and the identified genotypes were 6b, MM4 (W13B), and MM9 (PAP238A). CONCLUSIONS: HPV DNA frequency in patients with oral epithelial lesions was 11.3%. The genotypes MM4 and MM9 are uncommon in oral lesions, and they are characterized as high-risk HPV types in those types of lesions.     

In vitro secreted aspartyl proteinase activity of Candida albicans isolated from oral diseases and healthy oral cavities

The in vitro secreted aspartyl proteinase (SAP) activity of Candida albicans isolated from a variety of oral conditions, including healthy oral cavities, was determined. SAP activity (units/10(6) cells/ml, +/-SD) was 0.28 +/- 0.33 for pseudomembranous candidosis isolates (n = 18), 0.35 +/- 0.46 for chronic erythematous candidosis isolates (n = 21) and 0.30 +/- 0.32 for chronic hyperplastic candidosis isolates (n = 50). SAP activity of 0.19 +/- 0.22 was recorded for isolates from squamous cell carcinoma (n = 18), 0.26 +/- 0.37 for burning mouth syndrome isolates (n = 29), 0.25 +/- 0.38 for isolates from xerostomia (n = 15) and 0.39 +/- 0.50 for isolates from lichen planus (n = 13). The SAP activity of isolates from oral disease states was significantly (P < 0.05) higher than that recorded for 28 isolates from healthy mouths (activity of 0.04 +/- 0.03). However, there was no significant difference in the SAP activity between the three forms of clinical oral candidosis (P > 0.05). SAP activity was inhibited in control samples containing the SAP inhibitor, pepstatin A. These results indicate that C. albicans strains associated with oral disease have inherently higher SAP activity.     

The frequency of Candida in oral lichen planus

ABSTRACT – Histologic material of typical lichen planus lesions from 43 patients was studied. Two sections of each specimen were stained with hematoxylin-eosin and 10 sections by the PAS method. Only 1 of 43 biopsies was invaded by Candida, and hyphae were present in all of the 10 PAS-stained sections of this case. The results show that oral lichen planus has a considerably lesser susceptibility than oral leukoplakia to invasion by Candida albicans.     

Intergroup comparisons of oral lesions in HIV-positive South Africans

OBJECTIVES: To determine whether there are any differences in the oral manifestations of sub-groups of persons with HIV. These data could provide information for planning of oral health promotion and prevention programmes. DESIGN: A comparative inter-group cross-sectional investigation of the oral manifestations of HIV. Ethnic, gender and sexual orientation differences were taken into consideration. SETTING: Three large general hospitals that offer comprehensive medical investigations and care to persons with HIV. SUBJECTS AND METHODS: A total of 485 HIV-positive adults participated. Clinical examination and, where necessary, swabs or smears of lesions for microbiology, biopsies for histology. MAIN OUTCOME MEASURES: Presence of lesions, associated signs, incidence and type of micro-organisms. RESULTS: A total of 485 HIV-positive persons were examined over a period of 3 years consisting of 225 Blacks, 191 Coloureds (persons of ‘mixed’ descent) and 69 Whites. Data were analysed using, where relevant, the X² test or Fisher's exact test. Heterosexual males revealed a higher prevalence of all oral lesions combined when compared with heterosexual females. A similar finding was evident when HIV-associated periodontal diseases was compared in these two groups. Homosexual males had a higher prevalence of candidal infections than heterosexual males. Coloured heterosexuals had a higher prevalence of oral lesions combined than black heterosexuals. All these results showed statistical significance. CONCLUSIONS: The study tends to show that different patterns of prevalence emerge when inter-group comparisons are made of oral soft tissue diseases evident in HIV-infected South Africans.     

Bcl-2 expression in sequential biopsies of potentially malignant oral mucosal lesions assessed by immunocytochemistry

OBJECTIVE: To examine, for the first time Bcl-2 expression in sequential (autogenous) oral mucosal biopsies taken from the same sites in a gender, risk-factor matched, Caucasoid sample, over a 21-year period. DESIGN: Retrospective immunocytochemical longitudinal study of archival serial biopsies. MATERIALS AND METHODS: Computer records were used to identify biopsy specimens derived from 12 patients. These were divided into four groups: (1) Histologically innocuous lesions which remained histologically innocuous. (2) Dysplastic lesions which remained dysplastic. (3) Histologically innocuous lesions which later progressed to squamous cell carcinoma (SCC). (4) Dysplastic lesions which later progressed to SCC. This represented 65 biopsies in total. Bcl-2 expression was studied using mouse antihuman BCL-2 oncoprotein clone 124 (Dako, Denmark). RESULTS: Generally, there was a lack of Bcl-2 immunoreactivity in the epithelium, with one exception in dysplastic epithelium from a group (3) patient. CONCLUSION: These findings suggest that in our series, Bcl-2 is not expressed early in oral premalignant lesions and appears to contradict previous reports. Possible explanations for this disparity are considered.     

A molecular epidemiological study of sequential oral isolates of Candida albicans from terminally ill patients

The pattern of candidal colonisation was studied in a group of terminally ill patients receiving antifungal treatment for oral candidosis. A total of 43 isolates of C. albicans was collected pre- and post-antifungal treatment from patients up to a maximum period of 4 weeks. Isolates were analysed by electrophoretic karyotyping (EK) and by inter-repeat polymerase chain reaction (IR-PCR). Fifteen electrophoretic karyotypes and 17 IR-PCR profiles were identified. Sequential isolates from 10 patients yielded identical profiles in both EKs and IR-PCR analyses. In the case of four patients, minor differences in the profiles were obtained by either EK or IR-PCR. The findings suggest that antifungal treatment in this patient group fails to eradicate the original C. albicans strain, thereby allowing recolonisation of the oral cavity. The present study has also shown that either EK or IR-PCR is a useful typing approach in such epidemiological investigations.     

Toombak-associated oral mucosal lesions in Sudanese show a low prevalence of epithelial dysplasia

Clinical ( n =281) and histopathological ( n =141) characteristics of toombak-associated oral mucosal lesions detected in an epidemiological study in northern Sudan in 1992/93 are described. The lesional site in the majority of toombak users was the anterior lower labial groove and the lower labial mucosa. 4 degrees (1–4) of clinical severity of lesions, similar to those used to characterise Swedish snuff-dipper's lesion, were applied. An association between the severity of mucosal lesions and a longer lifetime duration (>10 years) of toombak use was found, but the severity was not related to the daily frequency of the habit. Parakeratosis, pale surface staining of the epithelium and basal cell hyperplasia were commonly observed, but epithelial dysplasia was infrequent (10/141). The most significant observation was a PAS-positive amorphous deposit between the lamina propria and the submucosa, found in 25/141 biopsies. The clinical and histopathological features of toombak lesions are closely similar to Swedish moist snuff-dipper's lesions and this may reflect the high alkalinity of these products, resulting in an alkaline burn on the oral mucosa following chronic exposure. The low prevalence of epithelial dysplasia implies a low risk of malignant transformation. Nevertheless, the high concentrations of tobacco-specific nitrosamines present in toombak, and the high prevalence of oral cancer in Sudan, mandate biopsy and careful histopathological analysis of any such lesions detected in habitues.     

Content and distribution of glycogen in oral epithelial dysplasia

Abstract— Forty-four oral lesions with epithelial dysplasia and 25 other benign and malignant lesionsof the oarl mucosa were examined after ataining with hematoxylin-eosin and diastase controlled PAS. The intensity of the PAS-Positivity for glycogen, The grade of dysplasia, the type of keratinization and the degreeof subepithelial inflmmation were recored. Histologically normal epithelium at the margins of the lesions were used as controls. The presence and amount of glycogen in normal epithlium varied with the Form of keratinization in that non-orparakeratinized epithelium was rich in glycogen where as there was a negative glycogen-reaction in orthokeratinized epithelium. The most striking feature was and abrupt limitation of the glycogen at the junction between nondysplastic and dysplastic epithlium. The difference in the amount of glycogen in normal and dysplastic epithlium as assessed semiquantitativbely, was statistically significant. The diastase controlled PAS-staining may therefore be a useful method of distinguishing dysplastic form nondysplastic epithlium in doubtjurl cases. Pseudoepitheliomatous hyperplastic epithelium covering granular cell myoblastoma did not contain any glycogen. Five of six squamous cell acrcinomas nand four verrucous carcinomas contained no demosstrable glycogen. Glycogen was present in the epithelium of the cases of lichen planus and "denture hyperplasia" investigated.     

Histopathologic and ultrastructural studies of oral mucosa with Candida infection

Eighteen oral mucosal biopsies with Candida infection were studied with light and electron microscopy. Under light microscopy, candidal infected oral mucosa was classified with epithelial hyperplasia, 15 cases and epithelial dysplasia, three cases. Four of 15 epithelial hyperplasias showed marked parakeratosis, and high grade acanthosis with many eosinophilic cells in the spinous cell layers. Epithelial dysplasia was characterized by atrophy of the spinous cell layers and increased nucleocytoplasmic ratio in the basal cell layers. Ultrastructurally, candidal infected oral mucosa showed numerous small desmosomes and the interdigitation of cytoplasmic membranes between spinous cells in both epithelial hyperplasia and epithelial dysplasia. Moreover, eosinophilic spinous cells, observed predominantly in epithelial hyperplasia showed intricate arrangement of dense tonofibrils. These ultrastructural findings seemed to give rise to mechanical strength between spinous cells in oral mucous epithelium with Candida infection. Results in this study suggest that excessive hyperplasia of candidal infected oral mucosa might be a protective reaction to the invasion of candidal pseudohyphae, but not associated with precancerous conditions.