High prevalence of non-albicans yeasts and detection of anti-fungal resistance in the oral flora of patients with advanced cancer

Palliative oral care in terminal cancer patients: Integrated review

BACKGROUND

Palliative care (PC) aims to improve quality of life in patients and its families against life threatening diseases, through suffering’s prevention and relief. It is the duty of the dental surgeon to possess the knowledge needed to treat a patient with little life span, in order to establish an adequate treatment plan for each situation.

AIM

To synthesize the published evidence on oral conditions, impact, management and challenges in managing oral conditions among palliative patients.

METHODS

Articles were selected from PubMed and Scopus electronic platforms, using a research strategy with diverse descriptors related to “palliative care”, “cancer” and “oral health”. The article’s selection was done in two phases. The first one was performed by the main researcher through the reading of the abstracts. In the second phase two researchers selected eligible articles after reading in full those previous selected. Data was tabulated and analyzed, obtaining information about what is found in literature related to this subject and what is necessary to be approached in future researches about PC.

RESULTS

As results, the total of 15 articles were eligible, being one a qualitative analysis, 13 (92.8%) clinical trials and one observational study. Of the 15 articles, 8 (53.4%) involved questionnaires, while the rest involved: one systematic review about oral care in a hospital environment, 2 oral exams and oral sample collection, one investigation of terminal patient’s (TP) oral assessment records, 2 collection of oral samples and their respective analysis and one treatment of the observed oral complications.

CONCLUSION

It can be concluded that the oral manifestations in oncologic patients in terminal stage are, oral candidiasis, dry mouth, dysphagia, dysgeusia, oral mucositis and orofacial pain. Determining a protocol for the care of these and other complications of cancer – or cancer therapy – based on scientific evidence with the latest cutting-edge research results is of fundamental importance for the multidisciplinary team that works in the care of patients in PC. To prevent complications and its needed to initial the dentist as early as possible as a multidisciplinary member. It has been suggested palliative care protocol based on the up to date literature available for some frequent oral complications in TP with cancer. Other complications in terminal patients and their treatments still need to have further studying.

Identification and susceptibility testing of oral candidiasis in advanced cancer patients

BACKGROUND

Patients with advanced cancer are prone to develop different opportunistic oral infection due to anti-cancer treatment or the malignancies themselves. Studies of oral fungal samples show an increased prevalence of non-Candida albicans species in mixed oral infections with Candida albicans. Non-C. albicans and C. albicans are associated with varying degrees of resistance to azoles, which may have implications for treatment. This study aimed to assess the diversity and antifungal susceptibility of Candida species detected in the oral cavity.

METHODS

An observational study with microbiological analysis was conducted. Clinical fungal isolates were collected from patients in a hospice unit in 2014-2016. Isolates were re-grown on chromID® Candida plates in 2020. Single colony of each species was re-cultivated and prepared for biochemical identification with a VITEK2® system and verified by gene sequencing. Etest was performed on RPMI agar, and the antifungals fluconazole, amphotericin B, anidulafungin and nystatin were applied.

RESULTS

Fifty-six isolates from 45 patients were identified. Seven different Candida species and one Saccharomyces species were detected. The results of biochemical identification were confirmed with sequencing analysis. Thirty-six patients had mono infection, and nine out of 45 patients had 2-3 different species detected. Of C. albicans strains, 39 out of 40 were susceptible to fluconazole. Two non-C. albicans species were resistant to fluconazole, one to amphotericin B and three to anidulafungin.

CONCLUSION

C. albicans was the predominant species, with a high susceptibility to antifungal agents. Different Candida species occur in both mono and mixed infections. Identification and susceptibility testing may therefore lead to more effective treatment and may prevent the development of resistance among patients with advanced cancer.

TRAIL REGISTRATION

The study Oral Health in Advanced Cancer was registered at ClinicalTrials.gov (#NCT02067572) in 20/02/2014.

Oral candidiasis in a specialist palliative care unit: assessment, diagnosis, management

OBJECTIVES

To evaluate current clinical practices of assessment, diagnosis and management of oral candidiasis in a specialist palliative care unit to improve patient outcomes through compliance with the Australian Commission on Safety and Quality in Health Care Antimicrobial Stewardship Clinical Care Standard.

METHODS

A clinical audit cycle: review of 100 patient records preceded an educational intervention delivered over 4 weeks to clinical stakeholders, followed by a review of an additional 100 records.

RESULTS

Eleven patients in each cohort had oral candidiasis. A statistically significant improvement in documented rates of oral examination (33% to 51%, p=0.015) and appropriate microbiological testing (0% to 63.6%, p=0.004) was achieved. Documentation of oral symptoms and prescribing practices were unchanged.

CONCLUSIONS

Meaningful changes in practice relating to oral assessment and diagnosis of oral candidiasis are possible. Future iterations of the audit cycle may benefit from multimodal interventions to encourage further practice change.

In vitro antimicrobial effects of chitosan on microcosm biofilms of oral candidiasis

OBJECTIVE

This study assessed the effects of chitosan (CS) on microcosm biofilms derived from saliva of patients with Candida-associated denture stomatitis.

METHODS

Five removable denture wearers with denture stomatitis were included in the study. The minimum inhibitory concentration (MIC) of CS against clinical isolates of Candida albicans was determined according to the broth microdilution method. Pooled saliva from the donors was used as an inoculum for the formation of biofilms, which were developed during 72 h on acrylic surfaces in the Amsterdam Active Attachment model. The biofilms were then treated with different concentrations of CS, and the antibiofilm effects were evaluated through the quantification of colony-forming units (CFUs), total biomass (TB), metabolic activity (MA), lactic acid production (LAP), and cell viability (by confocal laser scanning microscopy). Chlorhexidine, miconazole, and nystatin were tested as positive controls, while the negative control (NC) was the untreated biofilm. Data were analyzed by 1-way ANOVA and Fischer LSD's post hoc test (α=0.05).

RESULTS

MIC values of CS ranged from 500 to 800 µg/mL. For CFUs, 2500 µg/mL CS was the most effective treatment in reducing total anaerobes, mutans streptococci, and Lactobacillus spp., significantly differing from the controls. For C. albicans CFUs, CS and positive controls did not differ from each other but led to significant reductions compared to NC. Regarding TB, MA, LAP, and cell viability, 2500 µg/mL CS promoted the greatest reductions compared to NC.

CONCLUSION

CS has similar or superior effects to conventional active principles on important parameters of oral candidiasis microcosm biofilms.

CLINICAL RELEVANCE

The antibiofilm effects of CS show that this compound has great potential to improve the clinical condition of denture stomatitis patients, and formulations containing this natural polymer could be useful for controlling oral candidiasis.

MASCC/ISOO expert opinion on the management of oral problems in patients with advanced cancer

PURPOSE

The Palliative Care Study Group in conjunction with the Oral Care Study Group of the Multinational Association for Supportive Care in Cancer (MASCC) formed a sub-group to develop evidence-based guidance on the management of common oral problems in patients with advanced cancer.

METHODS

This guidance was developed in accordance with the MASCC Guidelines Policy. A search strategy for Medline was developed, and the Cochrane Database of Systematic Reviews and the Cochrane Central Register of Controlled Trials were explored for relevant reviews and trials, respectively. Guidance was categorised by the level of evidence, and "category of guideline" (i.e., "recommendation", "suggestion" or "no guideline possible").

RESULTS

Twelve generic suggestions (level of evidence - 5), three problem-specific recommendations and 14 problem-specific suggestions were generated. The generic suggestions relate to oral hygiene measures, assessment of problems, principles of management, re-assessment of problems and the role of dental/oral medicine professionals.

CONCLUSIONS

This guidance provides a framework for the management of common oral problems in patients with advanced cancer, although every patient requires individualised management.

Oropharyngeal Candida Colonization in Patients with Acute Myeloid Leukemia

Objectives:

Oral candidiasis has increased in recent years because of the increasing number of high-risk populations. The prevalence of Candida species is different worldwide because of the difference between population characteristics, sampling protocols, and geographic regions. Therefore, determining the more prevalent Candida species in different geographic regions seems essential. This study aimed to determine the more prevalent Candida species in acute myeloid leukemia (AML) patients in comparison with healthy individuals in Iran in 2016.

Materials and Methods:

Fifty-one patients with AML and 62 healthy controls participated in this cross-sectional study. Samples were collected using a swab rubbed softly on the dorsal surface of the tongue and the oropharynx. The samples were cultured on CHROMagar Candida for 2 to 4 days. For differentiation between albicans and non-albicans species, positive samples were linearly inoculated on Corn Meal Agar with Tween-80. Candida species were identified using a microscope. Data were analyzed using chi-square and Fisher’s exact tests.

Results:

Candida colonization was more frequent in AML patients (41.2%) in comparison with healthy participants (38.7%). Candida glabrata (C. glabrata; 27.5%) and Candida albicans (C. albicans; 32.3%) were the most common isolated species in the AML patients and the controls, respectively. There was a significant decrease in the frequency of C. albicans (P=0.022) and a significant increase in the frequency of C. glabrata (P=0.002) in the AML patients in comparison with the controls.

Conclusion:

AML patients are more susceptible to candidiasis. C. glabrata is the dominant Candida species in AML patients.

Microbial interactions and immunity response in oral Candida species

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

Alteration in Oral Flora and Effect of Mucositis in Head and Neck Cancer Patients Undergoing Chemo-radiotherapy

The main aim of this study is to determine the various types of oral bacteria and yeast. Present in oral flora of head and neck cancer patients at different stages of chemo-radiotherapy, and compare it with the control group (patients with contralateral healthy mucosa). Seventy seven patients with proven history of squamous cell carcinoma were included in the study. The oral mucosa profile was assessed for bacterial manifestations in swab samples from both the sites of the patients. The grade of mucositis was charted out for all patients during the second and third week of radiotherapy. The study revealed that all isolated oral flora showed a non-significant increase during radiotherapy, while there was a decrease in oral flora in post RT. However, E. faecalis showed a non- significant decrease during RT, while Citrobacter showed an increase. Candida albicans showed 83% non- significant decrease post- radiotherapy. When these floras were correlated with grade of mucositis, an insignificant increase in flora was found in G2 and G3 stage of mucositis. In this study, the effect of radiation was evaluated on oral flora of head and neck cancer patients and compared with contralateral healthy mucosa of the patients. Various changes were observed during and after radiation therapy. In patients with head and neck cancer the normal oral flora are replaced by pathogenic flora during radiotherapy, and the latter is responsible for infections in post- radiation phase.

Antifungal effect of Atorvastatin against Candida species in comparison to Fluconazole and Nystatin

Background and aims

Atorvastatin is a plasma cholesterol-lowering drug which applies antifungal effects by inhibiting the production of yeast cell wall ergostrol. The aim of present study was to investigate in-vitro susceptibility of candida species to atorvastatin, in comparison to nystatin and fluconazole.

Methods

Minimum inhibitory concentrations (MIC) and minimum fungicidal concentrations (MFC) were determined using serial dilution. Candida strains isolated from 35 patients receiving cancer chemotherapy in Isfahan, Seyyed-al-Shohada Hospital and analyzed by Kruskal-Wallis and Mann Whitney statistical methods.

Results

Candida isolates included 5 strains, C. albicans, C. glabrata, C. kefyr, C. stellatoidea and C. krusei. All five strains appeared to be resistant to nystatin and fluconazole but sensitive to atorvastatin with no statistically significant difference. The MFC of atorvastatin was significantly lower in comparison to both nystatin and fluconazole for all five strains (p value<0.05). There was no significant difference between the MFCs of 5 strains for fluconazole and atorvastatin. However, MFC of nystatin differed significantly for C. albicans and C. kefyr (p=0.007).

Conclusion

The results showed that all strains were sensitive to atorvastatin and resistant to nystatin and fluconazole. Atorvastatin MIC for C. albicans, C. krusei and C. stellatoidea was equivalent to its serum level used to treat hyperlipidemia and was above such level for both C. glabrata and C. kefyr.

The severity of denture stomatitis as related to risk factors and different Candida spp

OBJECTIVES

1) To select patients with Candida-related denture stomatitis (DS) and to study possible risk factors associated with DS, 2) to evaluate the severity of DS according to Newton's classification, and 3) to investigate the association between the presence of non-albicans Candida spp. (NAC) or mixed Candida spp. and the severity of DS.

STUDY DESIGN

Eighty-two patients with Candida-positive DS have undergone 1) filling in the interview questionnaire, 2) clinical examination, and 3) microbiologic examination.

RESULTS

A total of 113 Candida spp. isolates were obtained from Candida-positive DS patients: C. albicans (as a single species) in 47/82 (57%) patients (study group A [SG_A]) and NAC/mixed Candida spp. in 35/82 (43%) patients (SG_B). Univariate logistic regression analysis showed that older age, longer age of the mandibular denture, and ex-smoker status were associated with SG_A. A multivariate model revealed no significant predictor of DS severity. Patients from SG_A were 3 times as likely to have DS type I, while patients from SG_B were 4.9 times as likely to have DS type III.

CONCLUSIONS

Our results show the association between type III of DS (by Newton's classification) and the presence of NAC or mixed Candida spp. in denture wearers.

Denture Stomatitis: Causes, Cures and Prevention

Removable dentures are worn by 20% of the UK population and two thirds of these individuals have denture stomatitis. Poor oral hygiene is commonplace among this group, as is smoking and xerostomia, which also contribute to the development of denture stomatitis. A complex polymicrobial biofilm is able to proliferate on the surface of denture materials and matures to form visible denture plaque. This denture plaque biofilm stimulates a local inflammatory process that is detectable clinically as erythema, and hyperplasia. Systemically, denture plaque represents a potential risk factor for systemic disease, in particular aspiration pneumonia. Respiratory pathogens have been detected in the denture plaque and overnight denture wear has been linked to an increased risk of aspiration pneumonia. There is a general lack of evidence on the adequate management of denture stomatitis and we present a protocol for use in the primary care setting.

Laboratory-Based Investigation of Denture Sonication Method in Patients with Candida-Associated Denture Stomatitis

PURPOSE

Denture stomatitis (DS) is a disease characterized by inflammation and erythema of the oral mucosa areas covered by the denture. Multifactorial etiological factors contribute to DS, but it seems that Candida plays the key role. The aim of the study was to evaluate the denture sonication method to: (i) increase the possibility of diagnosing patients with Candida-associated DS; (ii) detect and identify the mixed Candida spp., and (iii) determine the Candida colony forming units (CFU) and its possible relationship with DS severity, based on Newton's classification.

MATERIALS AND METHODS

The cross-sectional study conducted at the Clinic for Dental Prosthetics, Belgrade (Serbia) from June 2013 to December 2014 enrolled edentulous patients with dentures (n = 250). Patients without DS (n = 20) were the control group (CG). The patients' data were collected, and patients with DS (study group/SG) were selected and divided into SG Candida+ and SG Candida-. Based on severity of DS, the SG patients were classified in 3 groups (Newton's classification). Four sampling methods were applied to detect patients with Candida-associated DS: mucosa swab, denture swab, oral rinse, and denture sonication method. The sensitivity and specificity of denture sonication method were shown using the receiver operating characteristic (ROC) curve and the area under the curve (AUC).

RESULTS

In 97 (38.8%), out of 250 clinically examined patients, DS was diagnosed. In 82 (84.5%), out of 97 mycologically examined patients, Candida-associated DS was detected when denture sonication method was applied. Additionally, using the denture sonication method we observed: (i) the largest number of Candida positive patients compared to other sampling methods (p < 0.0001); (ii) the highest number of Candida CFU/ml (10⁵ ), and (iii) the possibility to detect mixed Candida cultures. The largest number of patients with Candida-associated DS showed type II (60%) DS, followed by type I (21%), and type III (19%) DS.

CONCLUSION

The denture sonication method is easy, accurate, and sensitive, and increases the possibility of diagnosing patients with Candida-associated DS. Additionally, yeast quantification, mixed Candida spp., and non-albicans Candida were detectable when cultivation on Candida CHROMagar was performed. It was not possible using conventional methods, such as swab or oral rinse.

Opportunistic Microorganisms in Oral Cavity According to Treatment Status in Head and Neck Cancer Patients

Introduction

Cancer patients receiving chemotherapy and/or radiation therapy are prone to many predisposing factors like immunosuppression, imbalance in the oral flora, hypo-salivation and local tissue damage. Therefore, considered to be at higher risk for oral bacterial and fungal infection than the general population.

Aim

To study oropharyngeal flora in head and neck cancer patients under treatment and to correlate their incidence according with Chemotherapy cycles and Radiochemotherapy.

Materials and Methods

Total 110 patients were selected for study, those were further divided into two groups, group I under Chemotherapy (CT) - 55 patients and group II under Radiochemotherapy (RCT) - 55 patients and 50 healthy individuals were taken as control. Saliva sample was collected from control and study group and inoculated on Blood agar, MacConkey agar and Sabouraud's Dextrose Agar (SDA). The identification of bacterial and fungal isolates was done by standard microbiological methods and result was calculated according to cycles of Chemotherapy and Radiochemotherapy combined. Significant differences between patients were tested using the Chi-square test or Fisher's exact test. A p-value less than 0.05 was considered as statistically significant.

Result

There were 149 culture isolates from 110 patient in which Gram Negative Bacilli (GNB) found in 63.6%, Candida spp. in 50%, Staphylococcus aureus in 8% and Normal commensal of oral cavity in 13.6% patients in study group and this was higher than control group and this difference was statistically significant in relation to all isolates individually. Relatively more microorganism were isolated during RCT (56%) in compare to CT alone (44%), among GNB- Pseudomonas (27.7%,32.3%) and Klebsiella (25%,29.4%) were most frequently isolated during CT, RCT respectively. Candida spp. were more commonly isolated from patient on RCT (63.6%) than CT (36.3%) when compared to control group (20%) among which C. tropicalis was more prevalent species. Both GNB & Candida spp. were more commonly isolated in later chemotherapy cycles (CT4, CT5 CT6).

Conclusion

Colonisation of Gram negative bacilli & Candida spp. is directly related to number of chemotherapy cycles and combined cancer therapy. Hence, prophylactic medication for these two organisms should be incorporated along with cancer therapy.

A retrospective study of 606 cases of nasopharyngeal carcinoma with or without oropharyngeal candidiasis during radiotherapy

Background

To evaluate the clinical characteristics, treatment-related toxicities and survival in patients with nasopharyngeal carcinoma (NPC) with or without oropharyngealcandidiasis (OPC) during radiotherapy.

Methods

The current study was conducted with NPC patients undergoing radiotherapy at Sun Yat-Sen University Cancer Center between June 2011 and May 2012. A clinical diagnosis of candidiasis was determined on the basis of a positive potassium hydroxide (KOH) test and the presence of pseudomembranous (white) form of candidal overgrowth. The Cox proportional hazard regression model was used to test the association of OPC and related survival rates.

Results

Compared with the non-OPC group, the OPC group had significantly increased occurrence rates of grade 3–4 mucositis (14.5% vs. 7.4%, P = 0.049), anaemia (11.3% vs. 4.4%, P = 0.020), hepatotoxicity (4.8% vs. 1.1%, P = 0.021) and critical weight loss (85.5% vs. 56.6%, P<0.001) during radiotherapy. The OPC group had a significantly lower disease-free survival (DFS) (70.9% vs. 82.6%, P = 0.012), mainly as a result of a reduction in locoregional relapse-free survival (LRFS) (87.0%vs. 94.9%, P = 0.025). After stratification by T stage, the 5-year DFS in T3-4 patients were 82.0% and 68.8% in non-OPC and OPC groups, respectively (P = 0.022). Multivariate analyses indicated that OPC was a prognostic factor for LRFS and DFS.

Conclusions

OPC during radiotherapy may worsen the nutritional status of NPC patients according to weight loss and anaemia, leading to a negative impact on 5-year locoregional relapse-free survival and disease-specific survival. Further investigations are needed to explore whether prevention and treatment of OPC during radiotherapy will be useful.

Fatal bacterial septicemia in a bottlenose dolphin Tursiops truncatus caused by Streptococcus iniae

A captive 8 yr old male bottlenose dolphin Tursiops truncatus succumbed to septicemia with multisystemic inflammation including suppurative enteritis, encephalitis, and pneumonia with chronic pancreatitis. A pure culture of beta-hemolytic, catalase- and oxidase-negative, Gram-positive cocci was isolated from the hilar lymph nodes and pancreas. The isolate was identified by 16S rDNA sequencing as Streptococcus iniae. Histological examination of the digestive system revealed a mixed infection of both bacteria and fungus. Recognized as a pathogen in fish, dolphins, and humans, this is the first report of S. iniae in a dolphin in mainland China. As the number of managed animals in oceanariums is increasing, so is the frequency of contact with fish used as food for marine mammals and humans, highlighting the importance of education and appropriate personal protective protocols to minimize the risk of transmission. An understanding of marine mammal infectious disease organisms is essential to ensuring the health of marine mammals and humans coming into contact with such animals and their food. This study illustrates a systematic clinical, microbiological, and pathological investigation into a septicemic bottlenose dolphin infected with S. iniae. Our findings provide useful information for those involved in the diagnosis and control of infectious diseases in marine mammals and offer insight into an important zoonotic pathogen.

Oral Candidiasis among Cancer Patients Attending a Tertiary Care Hospital in Chennai, South India: An Evaluation of Clinicomycological Association and Antifungal Susceptibility Pattern

Oropharyngeal candidiasis is one of the common manifestations seen in cancer patients on cytotoxic therapy and invasion into deeper tissues can occur if not treated promptly. Emergence of antifungal drug resistance is of serious concern owing to the associated morbidity and mortality. The present study aims at evaluation of clinicomycological association and antifungal drug susceptibility among the 180 recruited patients with cancer on chemotherapy and/or radiotherapy with signs or symptoms suggestive of oral candidiasis. Speciation and antifungal susceptibility was done by Microbroth dilution method for fluconazole, Itraconazole, and Amphotericin B as per standard microbiological techniques. Chi-square test was used for statistical analysis (p < 0.05 was considered statistically significant). Candida albicans was the predominant species isolated (94) (58%) followed by Candida tropicalis (34) (20.9%). Fluconazole and Itraconazole showed an overall resistance rate of 14% and 14.8%, respectively. All the isolates were susceptible to Amphotericin B. There was a significant association between the presence of dry mouth and isolation of Candida (p < 0.001). Such clinicomicrobiological associations can help in associating certain symptoms with the isolation of Candida. Species level identification with in vitro antifungal susceptibility pattern is essential to choose the appropriate drug and to predict the outcome of therapy.

Oral yeast colonization in peritoneal dialysis and hemodialysis patients and renal transplant recipients

OBJECTIVE

We aimed to investigate the frequency of oral yeast colonization (OYC) and the risk factors for patients who received continuous ambulatory peritoneal dialysis (CAPD) or hemodialysis (HD) or were renal transplant recipients (RTRs). The patients admitted to the Nephrology Clinic at Ataturk University Medical School from January through April 2013 were included in the study. A questionnaire about risk factors was filled out, and swab cultures were taken from the tongue surface of each participant. OYC was detected in 32.1% of the RTRs, 40% of the HD patients, 20.9% of the CAPD patients, and 18% of the healthy control (HC) group. Of the 42 yeast strains isolated from the renal replacement therapy groups, 26 strains (61.9%) were Candida albicans, nine (21.4%) were Candida glabrata, two (4.7%) were Candida krusei, two (4.7%) were Candida kefyr, one (2.38%) was Candida parapsilosis, and two (4.7%) were Geotrichum candidum. Risk factors for OYC in the RTRs group included antibiotic use and the presence of dental prostheses; however, in patients with chronic renal failure undergoing CAPD, only the presence of dental prostheses was found to be a statistically significant risk factor. Although OYC was mostly detected in patients with chronic kidney disease (undergoing HD, a variety of isolated yeast strains in the RTRs was noted. The rates of OYC and isolated Candida species in CAPD were similar to those of the HC group.

Occurrence of oral Candida colonization and its risk factors among patients with malignancies in China

OBJECTIVES

Oral colonization of Candida could lead to later development of oropharyngeal candidiasis or candidemia among the immunocompromised patients. This study aims to describe the occurrence and risk factors of oral Candida colonization in patients with malignancies.

MATERIALS AND METHODS

From October 2012 to March 2013, 78 patients with pulmonary cancer (group I), 101 patients with gastrointestinal tract tumor (group II), 79 patients with hematopoietic system malignant tumor (group III), and 101 healthy controls were consecutively recruited in a hospital in Beijing, China. The oral rinse samples were taken and Candida species were identified; the enzymes activities were tested.

RESULTS

In total, 110 and 27 Candida strains were isolated from 91 patients and 26 controls, respectively. The oral colonization rate with Candida albicans in group III (12.7 %) was significant lower than that in group I (30.8 %), group II (33.7 %), and control group (25.7 %). The oral colonization rates with non-albicans Candida species in group I, group II, and group III were 15.4, 10.9, and 12.7 %, respectively, while only one non-albicans Candida strain was identified in control group. The non-albicans Candida species exhibited a lower virulence than C. albicans. Age was an independent risk factor for Candida colonization in patients with pulmonary cancer and digestive tract malignant tumor, "Teeth brush <1 time/day" was an independent risk factor for Candida colonization in patients with hematopoietic system tumor.

CONCLUSIONS

The differences of risk factors for oral Candida colonization in patients with different cancers require different strategies for the prevention and control of Candida infection.

CLINICAL RELEVANCE

Old aged patients with pulmonary cancer and digestive tract malignant tumor are high-risk population for Candida colonization. Increasing frequency of teeth brush might be helpful for preventing Candida colonization.

Assessment of Candida species colonization and denture-related stomatitis in bar- and locator-retained overdentures

The aim of this study was to assess the prevalence of denture-related stomatitis (DRS) in different attachment-retained overdenture wearers and its association with particular colonizing Candida species. Thirty-seven edentulous patients with implant-supported maxillary or mandibular overdentures were enrolled. A full clinical history was obtained, including details of patients' oral hygiene practices and the levels of erythema based on Newton's classification scale. Swabs were taken from the palate and investigated mycologically to identify the yeast colonies. Quantitative and qualitative microbiological assessments were performed, which included recording the total numbers of colonies (cfu), their color, and their morphological characteristics. Significant differences were found in cfu values between the attachment and inner surfaces of locator- and bar-retained overdentures (P < .05). Candida albicans was the most common species in both evaluations, being isolated from 81.3% of bar-retained overdentures and 38.1% of locator-retained overdentures. DRS developed in all patients using bar-retained overdentures but in only 71.4% of those using locator-retained overdentures. No statistically significant relationship was found between bar and locator attachments according to smoking habit, overnight removal, or plaque and gingival indices (P > .05).

The Candida pathogenic species complex

Candida species are the most common causes of fungal infection. Approximately 90% of infections are caused by five species: Candida albicans, Candida glabrata, Candida tropicalis, Candida parapsilosis, and Candida krusei. Three (C. albicans, C. tropicalis, and C. parapsilosis) belong to the CTG clade, in which the CTG codon is translated as serine and not leucine. C. albicans remains the most commonly isolated but is decreasing relative to the other species. The increasing incidence of C. glabrata is related to its reduced susceptibility to azole drugs. Genome analysis suggests that virulence in the CTG clade is associated with expansion of gene families, particularly of cell wall genes. Similar independent processes took place in the C. glabrata species group. Gene loss and expansion in an ancestor of C. glabrata may have resulted in preadaptations that enabled pathogenicity.

Oral health conditions affect functional and social activities of terminally ill cancer patients

PURPOSE

Oral conditions are established complications in terminally ill cancer patients. Yet despite significant morbidity,the characteristics and impact of oral conditions in these patients are poorly documented. The study objective was to characterize oral conditions in terminally ill cancer patients to determine the presence, severity, and the functional and social impact of these oral conditions.

METHODS

This was an observational clinical study including terminally ill cancer patients (2.5–3-week life expectancy). Data were obtained via the Oral Problems Scale (OPS) that measures the presence of subjective xerostomia, orofacial pain, taste change, and the functional/social impact of oral conditions and a demographic questionnaire. A standardized oral examination was used to assess objective salivary hypofunction, fungal infection, mucosal erythema, and ulceration. Regression analysis and t test investigated the associations between measures.

RESULTS

Of 104 participants, most were ≥50 years of age,female, and high-school educated; 45 % were African American, 43 % Caucasian, and 37 % married. Oral conditions frequencies were: salivary hypofunction (98 %), mucosal erythema (50 %), ulceration (20 %), fungal infection(36 %), and other oral problems (46 %). Xerostomia, taste change, and orofacial pain all had significant functional impact; p <.001, p =.042 and p <.001, respectively. Orofacial pain also had a significant social impact (p <.001). Patients with oral ulcerations had significantly more orofacial pain with a social impact than patients without ulcers (p =.003). Erythema was significantly associated with fungal infection and with mucosal ulceration (p <.001).

CONCLUSIONS

Oral conditions significantly affect functional and social activities in terminally ill cancer patients. Identification and management of oral conditions in these patients should therefore be an important clinical consideration.

In vitro antifungal effect and inhibitory activity on biofilm formation of seven commercial mouthwashes

OBJECTIVE

To investigate the antifungal ability of seven over-the-counter mouthwashes against planktonic and sessile Candida albicans and Candida krusei.

MATERIALS AND METHODS

The seven mouthwashes studied were Listerine, compound chlorhexidine solution, povidone iodine solution (PV-I), cetylpyridinium chloride solution, Colgate Plax, Crest Prohealth Mouthwash, and NaHCO3 . The antifungal ability of each mouthwash against ATCC90028, ATCC6258, and 10 clinical C. albicans isolates was tested using disk diffusion tests, the broth microdilution method, and biofilm testing with two different XTT-reduction assays. Fluconazole was used as a positive control, and the experiments were performed in triplicate.

RESULTS

Chlorhexidine and cetylpyridinium chloride had the largest inhibition zones for ATCC90028 and ATCC6258 (18.6 ± 3.5 and 19 ± 1.6 mm, respectively). Cetylpyridinium chloride was the most effective at inhibiting all of the planktonic C. albicans strains and ATCC6258 with the minimum inhibitory concentration (MIC). As the maturity of the biofilms increased, the change in sessile cell MIC of the mouthwashes was much smaller than that of fluconazole. For the mature biofilms, chlorhexidine, PV-I, and cetylpyridinium chloride produced the greatest reductions in metabolism (60-80%).

CONCLUSION

Most of these seven mouthwashes had significant antifungal activity for both planktonic and sessile Candida species.

Oral bacteria and yeasts in relationship to oral ulcerations in hematopoietic stem cell transplant recipients

BACKGROUND

Oral mucositis is a serious and debilitating side effect of conditioning regimens for hematopoietic stem cell transplant (HSCT). Through HSCT, the homeostasis in the oral cavity is disrupted. The contribution of the oral microflora to mucositis remains to be clarified. The aim of our study was to investigate the relationship between yeasts, bacteria associated with periodontitis, and oral ulcerations in HSCT recipients.

METHODS

This prospective observational study included 49 adult HSCT recipients. Twice weekly, oral ulcerations were scored, and oral rinsing samples were obtained. Samples were evaluated for the total bacterial load; the Gram-negative bacteria: Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Parvimonas micra, Fusobacterium nucleatum, Tannerella forsythia, and Treponema denticola; and the yeasts: Candida albicans, Candida glabrata, Candida kefyr, Candida krusei, Candida parapsilosis, and Candida tropicalis using real-time polymerase chain reaction with specific primers and probes. Explanatory variables for oral ulcerations were calculated using the multilevel generalized estimated equations (GEE) technique.

RESULTS

None of the samples was positive for A. actinomycetemcomitans, while F. nucleatum was found most often (66 % of samples). C. albicans was the most isolated yeast (88 % of samples), whereas C. parapsilosis was found in only 8 % of the samples. Multivariate GEE analyses identified P. gingivalis, P. micra, T. denticola, F. nucleatum, C. glabrata, and C. kefyr as significant explanatory variables of oral ulcerations.

CONCLUSIONS

Our data indicate that P. gingivalis in particular, but also P. micra, T. denticola, F. nucleatum, C. glabrata, and C. kefyr may play a role in ulcerative oral mucositis in patients undergoing HSCT.

Incidence and risk factors for infection in oral cancer patients undergoing different treatments protocols

BACKGROUND

Over the past decade, advances in cancer treatments have been counterbalanced by a rising number of immunosuppressed patients with a multitude of new risk factors for infection. Hence, the aim of this study was to determine risk factors, infectious pathogens in blood and oral cavity of oral cancer patients undergoing different treatment procedures.

METHODS

The present prospective cohort analysis was conducted on the patients undergoing treatment in the radiotherapy unit of Regional Cancer Institute, Pt. B.D. Sharma University of Health Sciences, Rohtak, Haryana, during the period of January 2007 to October 2009. Total 186 patients with squamous cell carcinoma of oral cavity were analyzed in the study. Based on treatment procedures patients were divided into three groups, group I were under radiotherapy, group II under chemotherapy and group III were of radio chemotherapy together. Clinical isolates from blood and oral cavity were identified by following general microbiological, staining and biochemical methods. The absolute neutrophile counts were done by following the standard methods.

RESULTS

Prevalent bacterial pathogens isolated were Staphylococcus aureus, Escherichia coli, Staphylococcus epidermidis, Pseudomonas aeruginosa, Klebsiella pneumonia, Proteus mirabilis, Proteus vulgaris and the fungal pathogens were Candida albicans, Aspergillus fumigatus. The predominant gram negative bacteria, Pseudomonas aeruginosa and Klebsiella pneumonia were isolated from blood of radiotherapy and oral cavity of chemotherapy treated cases respectively. The predominance of gram positive bacteria (Staphylococcus aureus and Staphylococcus epidermidis) were observed in blood of chemotherapy, radio chemotherapy cases and oral cavity of radiotherapy, radio chemotherapy treated cases. Our study also revealed the presence of C. albicans fungi as most significant oral cavity pathogens in radiotherapy and radio chemotherapy cases.

CONCLUSION

Gram positive bacteria and Gram negative were reported from the blood of all the three groups of patients. Oral mucositis played a significant role in oral cavity infection and make patients more prone to C. albicans infection.

Antifungal, cytotoxic, and immunomodulatory properties of tea tree oil and its derivative components: potential role in management of oral candidosis in cancer patients

Candida albicans forms oral biofilms that cause disease and are difficult to treat with conventional antifungal agents. Tea tree oil (TTO) is a natural compound with reported antimicrobial and immunomodulatory activities. The aims of the study were to evaluate the antifungal efficacy of TTO and key derivatives against C. albicans biofilms, to assess the toxicological effects of TTO on a clinically relevant oral cell line, and to investigate its impact on inflammation. TTO and its derivatives were examined against 100 clinical strains of C. albicans. Planktonic minimum inhibitory concentrations (MICs) were determined using the CLSI M-27A broth microdilution method. Sessile MICs were determined using an XTT reduction assay. Inhibition, time-kill, and mode of action studies were performed. OKF6-TERT2 epithelial cells were used for cytotoxicity and cytokine expression assays. Planktonic C. albicans isolates were susceptible to TTO, terpinen-4-ol (T-4-ol), and α-terpineol, with an MIC₅₀ of 0.5, 0.25, and 0.25%, respectively. These three compounds also displayed potent activity against the 69 biofilm-forming strains, of which T-4-ol and α-terpineol displayed rapid kill kinetics. For all three compounds, 1 × MIC₅₀ effectively inhibited biofilm growth when C. albicans were treated at 0, 1, and 2 h post adhesion. By scanning electron microscopy analysis and PI uptake, TTO and derivative components were shown to be cell membrane active. TTO and T-4-ol were cytotoxic at 1 × MIC₅₀, whereas at 0.5 × MIC₅₀ T-4-ol displayed no significant toxicity. Transcript and protein analysis showed a reduction of IL-8 when treated with TTO and T-4-ol. These data provide further in vitro evidence that TTO and its derivative components, specifically T-4-ol, exhibit strong antimicrobial properties against fungal biofilms. T-4-ol has safety advantages over the complete essential oil and may be suitable for prophylaxis and treatment of established oropharyngeal candidosis. A clinical trial of T-4-ol is worthy of consideration.

Silver colloidal nanoparticles: antifungal effect against adhered cells and biofilms of Candida albicans and Candida glabrata

The aim of this study was to evaluate the effect of silver nanoparticles (SN) against Candida albicans and Candida glabrata adhered cells and biofilms. SN (average diameter 5 nm) were synthesized by silver nitrate reduction with sodium citrate and stabilized with ammonia. Minimal inhibitory concentration (MIC) tests were performed for C. albicans (n = 2) and C. glabrata (n = 2) grown in suspension following the Clinical Laboratory Standards Institute microbroth dilution method. SN were applied to adhered cells (2 h) or biofilms (48 h) and after 24 h of contact their effect was assessed by enumeration of colony forming units (CFUs) and quantification of total biomass (by crystal violet staining). The MIC results showed that SN were fungicidal against all strains tested at very low concentrations (0.4-3.3 μg ml(-1)). Furthermore, SN were more effective in reducing biofilm biomass when applied to adhered cells (2 h) than to pre-formed biofilms (48 h), with the exception of C. glabrata ATCC, which in both cases showed a reduction ∼90%. Regarding cell viability, SN were highly effective on adhered C. glabrata and respective biofilms. On C. albicans the effect was not so evident but there was also a reduction in the number of viable biofilm cells. In summary, SN may have the potential to be an effective alternative to conventional antifungal agents for future therapies in Candida-associated denture stomatitis.

Bioactivity and cellular structure of Candida albicans and Candida glabrata biofilms grown in the presence of fluconazole

OBJECTIVE

The aim of this study was to evaluate whether fluconazole (FLZ) could affect the bioactivity and cellular structure of Candida albicans or Candida glabrata biofilms grown in the presence of FLZ.

MATERIALS AND METHODS

Tokens were fabricated using poly(methylmethacrylate) resin (PMMA) in a hot water bath. Salivary pellicles were formed on the PMMA surface, and biofilms of a reference strain and two clinical isolates of C. albicans (ATCC 90028, P01 and P34) and C. glabrata (ATCC 2001, P11 and P31) were developed for a period of 48 h. Control and experimental groups were formed. FLZ at the bioavailable concentration in saliva (2.56 μg/mL) was added to the medium of the experimental group. The culture mediums of the control and experimental groups were changed after 24h. The bioactivities of the biofilms were evaluated using an XTT reduction colorimetric assay. The cellular structure was analysed by confocal scanning laser microscopy and by transmission electron microscopy. The data were analysed by the independent sample Student's t-test, with the significance level set at 5%.

RESULTS

The presence of FLZ decreased the bioactivity of all C. albicans biofilms (p<0.001), however, it did not change the cellular structure of C. albicans P34. Regarding the C. glabrata biofilm bioactivity and structure, no statistically significant differences were found between the control and experimental groups.

CONCLUSION

FLZ, at the bioavailable concentration present in saliva, interferes with the development of C. albicans biofilms, but does not interfere with the development of C. glabrata biofilms.

Symptoms of the oral cavity and their association with local microbiological and clinical findings--a prospective survey in palliative care

PURPOSE

Symptoms of the oral cavity clearly encompass more than radiation or chemotherapy-induced mucositis. Still, the burden of oral symptoms in palliative care has hardly been addressed directly, and considerations towards underlying disease processes have often been extrapolated from oncology patients.

METHODS

We therefore conducted a prospective explorative survey with pilot character on patients on a specialized palliative care unit, describing symptom pattern (self assessment), clinical signs, bacteriological, mycological and virological findings, and correlating features of clinical history.

RESULTS

Taste disturbances, dry mouth and the presence of Candida were found to be the most prevalent and correlating items. The broad spectrum of further symptoms, signs and findings did not show relevant correlations and did not permit any unilateral causal attributions.

CONCLUSIONS

Apart from the described focus on Candida colonisation/infections, a symptom-guided polypragmatic approach therefore seems to be justifiable for patients with oral symptoms in palliative care.

Candida albicans and C. tropicalis Isolates from the Expired Breathes of Captive Dolphins and Their Environments in an Aquarium

Genotypes of Candida spp. isolated from exhalation of 20 dolphins, 11 water samples from captive pools, and 24 oral cavities of staff members in an aquarium using a combination of multiple drug resistance 1 gene (MDR1) and the internal transcribed spacer (ITS) 1 5.8s-ITS 2 regions of ribosomal RNA gene (ITS rDNA) sequences were studied. The holding ratios of the dolphins, captive pools, and staff members were 70, 90, and 29%, respectively. Isolated pathogenic yeast species common to the dolphins and environments were Candida albicans and C. tropicalis. Identical genotypes in both Candida spp. based on the combination of MDR1 and ITSrDNA were found in some dolphins, between a dolphin and a staff, among dolphins and environments, and among environments. The results indicated the diffusion and exchange of pathogenic yeasts at the aquarium among dolphins and environments. The isolates at the aquarium showed higher rates of resistance to azole antifungals compared to reference isolates.

Candida glabrata and Candida albicans co-infection of an in vitro oral epithelium

BACKGROUND

Candida albicans is regarded as the leading of candidosis. However, Candida glabrata has emerged as an important pathogen of oral mucosa, occurring both singly or in mixed species infections, often with C. albicans. Compared with C. albicans, little is known about the role of C. glabrata in oral infection. The aim of this study was to examine single and mixed species infection of oral epithelium involving C. glabrata and establish its ability to invade and damage tissue.

METHODS

A reconstituted human oral epithelium (RHOE) was infected only with C. glabrata, or simultaneously with C. glabrata and C. albicans. The ability of both species to invade the tissue was examined using species specific peptide nucleic acid (PNA) probe hybridization and confocal laser scanning microscopy. Epithelial damage was assessed by measuring lactate dehydrogenase (LDH) activity.

RESULTS

Candida glabrata strains were able to colonize the RHOE, in a strain dependent manner. Candida glabrata single infection after 12 h, generally revealed no invasion of the RHOE, which contrasted with extensive tissue invasion demonstrated by C. albicans. Mixed infection showed that C. albicans enhanced the invasiveness of C. glabrata, and led to increased LDH release by the RHOE, which paralleled the observed histological damage.

CONCLUSIONS

The results obtained demonstrating enhanced invasion and increased tissue damage caused by mixed C. glabrata and C. albicans infections have important clinical significance and highlight the need to identify Candida species involved in oral candidosis.

[Candida albicans infection in patients with oral squamous cell carcinoma]

BACKGROUND/AIM

Systemic candidiasis in intensive care units remains an improtant problem due to antifungal resistance. Patients undergoing radiotherapy for head and neck cancer are at increased risk of developing oral candidiasis and they more frequent have prior fungi colonization. Due to identification of specific risk factors predisposing to fungal infection in order to threat such patients the aim of this study was to determine the presence of Candida species in patients with oral squamous cell carcinoma and compare it to the control subjects (patients with benign oral mucosal lesions).

METHODS

A total number of 30 consecutive oral cancer examined patients were included in this prospective study (24 men and 6 women with a mean age of 61.47 years, range 41-81 years). The control group consisted of 30 consecutive patients with histologically proven benign oral mucosal lesions (16 men and 14 women with a mean age of 54.53 years, range 16-83 years). The samples for mycological examination were obtained by using sterile cotton swabs from the cancer lesion surface and in the patients of the control group from the benign mucosal lesion surface. Samples were inoculated in Sabouraud dextrose agar. For identification purposes, Mackenzie germ tube test was performend on all isolates.

RESULTS

The prevalence of Candida was significantly higher in oral cancer patients than in control subjects (chi2 = 5.455, p = 0.020). Candida was found on nine of the 30 cancer surfaces; 5 (16.7%) were identified as non-albicans Candida and 4 (13.3%) as Candida albicans. In the control group, only Candida albicans was isolated from 2 (6.7%) patients. In this study, no statistically significant differences in the presence of Candida species was found with respect to gender, age, smoking, alcohol consumption, wearing of dental protheses and the site of cancer lesion.

CONCLUSION

The increased prevalence of yeasts on the surfaces of oral carcinoma indicates a need for their suppression before any cancer treatment. There was no evidence for an association between gender, age, smoking, alcohol consumption, wearing of dental protheses, the site of cancer lesion and the yeast presence.

Comparative Proteomic Analysis of Candida albicans and Candida glabrata

Introduction

Candida albicans and Candida glabrata are the two most common opportunistic pathogens which are part of the normal flora in humans. Clinical diagnosis of infection by these organisms is still largely based on culturing of these organisms. In order to identify species-specific protein expression patterns, we carried out a comparative proteomic analysis of C. albicans and C. glabrata.

Methods

We used “isobaric tag for relative and absolute quantitation” (iTRAQ) labeling of cell homogenates of C. albicans and C. glabrata followed by LC-MS/MS analysis using a quadrupole time-of-flight mass spectrometer. The MS/MS data was searched against a protein database comprised of known and predicted proteins reported from these two organisms. Subsequently, we carried out a bioinformatics analysis to group orthologous proteins across C. albicans and C. glabrata and calculated protein abundance changes between the two species.

Results and Conclusions

We identified 500 proteins from these organisms, the large majority of which corresponded to predicted transcripts. A number of proteins were observed to be significantly differentially expressed between the two species including enolase (Eno1), fructose-bisphosphate aldolase (Fba1), CCT ring complex subunit (Cct2), pyruvate kinase (Cdc19), and pyruvate carboxylase (Pyc2). This study illustrates a strategy for investigating protein expression patterns across closely related organisms by combining orthology information with quantitative proteomics.

Epidemiology of oral yeast colonization and infection in patients with hematological malignancies, head neck and solid tumors

BACKGROUND

The aim of this study was to investigate the epidemiology of oral yeast colonization and infection amongst cancer patients.

METHODS

Patients with solid tumor, head-neck cancer or hematological malignancy were recruited into the study. Demographic data on age, gender, type of cancer, preceding treatment with antibiotics, anti-fungal agents, chemotherapy, radiation or surgery and presence of dentures were recorded on admission. Oral examination and microbial swabs were obtained and yeast culture, identification and antifungal susceptibility performed.

RESULTS

Oral yeast colonization was prevalent in 56.8% (227/400) of all cancer patients and 18.9% (43/227) of those had clinical and microbiological evidence of infection. The incidence of oral candidiasis in yeast colonized patients was highest in head neck cancer (29.2%) followed by hematological malignancies (20.5%) and solid tumor (17%) patients. Age and dentures were identified as independent risk factors associated with yeast carriage. Candida albicans was the dominant (74%) species (497.5 per 1000 cancer admissions) followed by C. glabrata (11.5%), C. tropicalis (2.6%), C. krusei (2.6%) and C. parapsilosis (1.9%). The overall resistance to azoles was 28.2% (75/266). Resistance to specific drugs was seen for fluconazole (4.5%), itraconazole (11.7%), ketoconazole (11.3%), voriconazole (0.75%) and caspofungin (41.1%) but none to amphotericin B or nystatin.

CONCLUSIONS

The highest incidence of oral candidiasis amongst cancer patients was seen in head neck cancers. The majority of infections were caused by C. albicans but almost one third of patients harbored non-C. albicans strains such as C. glabrata which were often more resistant to anti-fungal agents.

Mechanisms of antifungal drug resistance in Candida dubliniensis

Candida dubliniensis was first described in 1995 and is the most closely related species to the predominant human fungal pathogen Candida albicans. C. dubliniensis is significantly less prevalent and less pathogenic than C. albicans and is primarily associated with infections in HIV-infected individuals and other immunocompromised cohorts. The population structure of C. dubliniensis consists of three well-defined major clades and is significantly less diverse than C. albicans. The majority of C. dubliniensis isolates are susceptible to antifungal drugs commonly used to treat Candida infections. To date only two major patterns of antifungal drug resistance have been identified and the molecular mechanisms of these are very similar to the resistance mechanisms that have been described previously in C. albicans. However, significant differences are evident in the predominant antifungal drug mechanisms employed by C. dubliniensis, differences that reflect its more clonal nature, its lower prevalence and characteristics of its genome, the complete sequence of which has only recently been determined.

Prevalence of Candida dubliniensis among cancer patients in Kuwait: a 5-year retrospective study

Despite close genetic and phenotypic relationship of Candida dubliniensis with Candida albicans, its role in human disease is mostly restricted to oral colonisation, particularly among HIV-infected patients. The prevalence of C. dubliniensis in association with other disease conditions has been infrequently reported. In this study, we present data on the prevalence of C. dubliniensis among yeast species isolated from cancer patients over a 5-year period. A total of 1445 yeast isolates recovered from respiratory specimens, blood, urine and oral swabs were analysed. Candida dubliniensis isolates were provisionally identified by phenotypic methods and their identity was further confirmed by species-specific amplification and/or sequencing of internally transcribed spacer region of rDNA. Antifungal susceptibility for fluconazole was determined by Etest. The number of isolates identified as C. dubliniensis, C. albicans and other yeast species were 71 (4.9%), 862 (59.6%) and 512 (35%) respectively. All the C. dubliniensis isolates originated from respiratory (5.9%) or oral (3.2%) specimens with an overall prevalence of 4.9%, and were found to be susceptible to fluconazole. The isolation of C. dubliniensis from respiratory or oral specimens and not from blood or urine specimens suggests that this species has preference to colonise these sites of human body.

Acetaldehyde production from ethanol and glucose by non-Candida albicans yeasts in vitro

BACKGROUND

Major environmental risk factors for upper digestive tract cancers are tobacco smoking, alcohol intake and poor oral hygiene. They all result in increased acetaldehyde (ACH) levels in saliva which has been shown to be carcinogenic. During alcohol challenge the oral microbiota is the main determinant of the local ACH concentration. Many bacteria and Candida albicans have been shown to be capable of ACH production. Moreover, chronic candidal mucositis can be carcinogenic. The ability of non-C. albicans Candida to produce ACH has not been studied.

AIM

The aim of this study was to explore the ability of non-C. albicans Candida species to produce ACH in vitro during ethanol and glucose incubation.

METHODS

A total of 30 non-C. albicans Candida isolates and one C. albicans reference strain were used. The cells were exposed to 11 mM of ethanol and to 100mM glucose in vitro. ACH was measured by gas chromatography.

RESULTS

All Candida isolates produced significant amounts of ACH in ethanol incubation. C. tropicalis isolates were the highest (252.3 microM) and C. krusei isolates were the lowest (54.6 microM) producers of ACH from ethanol. Only C.glabrata produced significant amounts of ACH by fermentation from glucose.

CONCLUSION

Colonization of oral mucosa with a non-C.albicans species such as C. glabrata, capable of producing carcinogenic amounts of ACH from both ethanol and glucose, may contribute to the development of oral cancer.

Oral candidosis in community-based patients with advanced cancer

Oral candidosis is a significant cause of morbidity in patients with advanced cancer. The objectives of the study were to determine the epidemiology, etiology, clinical features, and microbiological aspects of oral candidosis among community-based patients. The subjects were recruited from hospice day centers in England. The clinical component involved completion of a study questionnaire, assessment of performance status, clinical examination of the oral cavity, measurement of unstimulated whole salivary flow rate, measurement of stimulated whole salivary flow rate, and performance of an oral rinse. Oral swabs were taken from subjects with appearances indicative of oral candidosis. The laboratory component involved standard procedures to isolate, enumerate, and identify yeasts from the clinical specimens. Three hundred ninety patients participated in the study. Two hundred seventy-two (70%) patients had oral yeast carriage, and 51 (13%) patients had combined clinical and microbiological evidence of oral candidosis. On univariate analysis, the presence of oral candidosis was associated with poor Eastern Cooperative Oncology Group performance status, presence of a denture, usage of a systemic corticosteroid, the severity of xerostomia, a low unstimulated whole salivary flow rate, and a low stimulated whole salivary flow rate. Multivariate analysis identified poor Eastern Cooperative Oncology Group performance status, presence of a denture, usage of a systemic corticosteroid, and the severity of xerostomia as being independently associated with the presence of oral candidosis. Oral candidosis is relatively common in community-based patients with advanced cancer. Hence, such patients should be screened for oral candidosis and should also be screened for reversible factors that predispose to oral candidosis, such as poor dental hygiene and salivary gland dysfunction.

[An update on Candida dubliniensis]

Eleven years ago, Irish authors, using molecular biology, demonstrated the existence of Candida dubliniensis, a new species of Candida close to Candida albicans. Initially isolated from AIDS patients with oral candidiasis, this species was detected, even in immunocompetent patients. Recently, with new, easy to implement identification tests (latex, immunochromatography), numerous epidemiological studies were undertaken. In most studies, C. dubliniensis was most often identified in the oral cavity. In the absence of HIV infection, the proportion C. dubliniensis/C. albicans ranged from 1 to 5% but it increased to 15-20% in case of HIV infection. It should be stressed that, from an experimental point of view, the acquisition of a secondary resistance to fluconazole is more quickly obtained with C. dubliniensis that with C. albicans, this resistance remains exceptionally observed in clinical observations.