Evaluation of saliva flow rates, Candida colonization and susceptibility of Candida strains after head and neck radiation

Effects of photobiomodulation and bethanechol chloride treatment on salivary composition and flow rate in head and neck cancer patients undergoing radiotherapy: longitudinal interventional experimental clinical study

OBJECTIVE

To evaluate the efficacy of photobiomodulation therapy (PBMT) and bethanechol chloride (BC) on the quantity and quality of saliva in patients undergoing radiotherapy (RT) for head and neck cancer.

METHODS

Saliva samples were collected from patients before and after RT, who were treated with PBMT or BC. Clinical parameters, including salivary flow rate (SFR), pH, xerostomia, and concentrations of macro and microelements in saliva, were assessed. Data were compared and analyzed using a self-organizing map.

RESULTS

No significant changes were observed in SFR, pH, and xerostomia pre- and post-RT in both the PBMT and BC-treated groups. However, there was an increase in Cr levels in the BC group and a reduction in P levels in the PBMT group.

CONCLUSION

The results suggest that both PBMT and BC treatments can effectively mitigate the impacts of RT, since quality and quantity of saliva were maintained.

Evaluation of antifungal effect of amphotericin B in comparison with nystatin on Candida species derived from patients undergoing head-and-neck radiotherapy

Background

There is ample evidence showing the development of nystatin-resistant strains in patients undergoing malignancy treatment. Amphotericin B is a polyene antifungal drug that combines with ergosterol to cause cell death and is more effective on fungal species than routine antifungals such as nystatin. This study aimed to compare the effect of nystatin and amphotericin B on fungal species isolated from patients before and during head-and-neck radiotherapy.

Materials and Methods

This in vitro experimental study was performed on samples isolated from patients undergoing head-and-neck radiotherapy before and during radiotherapy at Sayed al-Shohada Hospital in Isfahan, Iran. The isolates were identified by polymerase chain reaction-restriction fragment length polymorphism. Antifungal effects were determined by the microdilution method based on clinical and laboratory standards institute standards and minimum inhibitory concentration (MIC), minimum lethal concentration (MFC), drug sensitivity, and resistance were measured. The data were analyzed by SPSS version 22 (level of significance: 0.05).

Results

Before radiotherapy, all albicans strains were sensitive to nystatin, whereas 71.4% were sensitive to amphotericin B. After radiotherapy, Candida albicans strains were 100% sensitive to nystatin and 75% sensitive to amphotericin B.

Conclusion

The present study showed that before radiotherapy, all species isolated from patients, including C. albicans, C. tropicalis, and C. glabrata, were sensitive to nystatin, whereas a percentage of albicans species showed resistance to amphotericin B. In the 2nd week of radiotherapy, the same as before radiotherapy, all species isolated from patients were sensitive to nystatin, whereas a percentage of albicans species showed resistance to amphotericin B. In general, the current study showed that before and after radiotherapy, the antifungal effect of nystatin is greater than amphotericin B.

Antifungal effect of atorvastatin in comparison with fluconazole on Candida species isolated from patients undergoing head-and-neck radiotherapy

Background

Head-and-neck radiotherapy can change oral Candida species and lead to the development of refractory oral candidiasis resistant to the commonly prescribed antifungal medications such as fluconazole. Atorvastatin exerts an antifungal effect by inhibiting the synthesis of fungal wall ergosterol and impairing mitochondrial function. This study aimed to compare the antifungal effects of fluconazole and atorvastatin on Candida species isolated from patients undergoing head-and-neck radiotherapy.

Materials and Methods

In this clinical in vitro study, swab samples were collected from 33 patients admitted to Isfahan Seyed-O-Shohada Hospital before the onset and 2 weeks after the initiation of radiotherapy. The antifungal effects of fluconazole and atorvastatin were evaluated by the microdilution test according to the Clinical and Laboratory Standards Institute standards, and measuring their minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC). Data were analyzed by the Mann-Whitney U-test and the statistical significance level was considered P < 0.05.

Results

The results showed that the MIC24, MIC48, and MFC of fluconazole were significantly lower than those of atorvastatin for Candida albicans, Candida tropicalis, and Candida glabrata both before (P < 0.001 for all) and during (P < 0.001 to P = 0.003) radiotherapy.

Conclusion

According to the results, fluconazole has antifungal effects comparable to those of atorvastatin, but in much lower doses. Atorvastatin showed optimal antifungal effects but in doses beyond the clinically applicable threshold.

Efficacy of combined administration of Baekhogainsam-Tang and low-dose pilocarpine on frequent intractable xerostomia: Study protocol for a randomized controlled trial

BACKGROUND

Intractable xerostomia is defined as the subjective perception of dry mouth and persistent salivary gland hypofunction. Pilocarpine is an approved salivary sialagogue that is frequently prescribed for the treatment of intractable xerostomia; however, it often exhibits more side effects at high-doses and limited effectiveness at low-doses. Baekhogainsam-Tang (BIT) is a common herbal formula used by patients complaining of sore throats and thirst. It seems that BIT can compensate for the insufficient effect of low-dose pilocarpine. However, no clinical trials have studied the efficacy of combined administration of BIT and low-dose pilocarpine for intractable xerostomia. We aim to assess the non-inferior efficacy and fewer side effects of combined administration of BIT and low-dose pilocarpine compared with the administration of high-dose pilocarpine.

METHODS

A randomized, open-label, parallel-group, multi-center trial will be conducted. A total of 120 patients with Sjogren's syndrome having an unstimulated salivary flow rate (SFR) ≤0.1 mL/min or who have undergone radiotherapy to the head and neck with an unstimulated SFR ≤0.25 mL/min will be recruited competitively. They will be randomly allocated to either the experimental or control groups. The experimental group will receive BIT herbal granules three times and pilocarpine (2.5-mg) four times daily; meanwhile, the control group will receive only 5-mg pilocarpine four times daily for 12 weeks. The primary outcome is unstimulated SFR after 12 weeks of treatment. Secondary outcomes are stimulated SFR after 12 weeks of medication, as well as differences and mean percentage changes in unstimulated and stimulated SFR, visual analog scale, salivary scintigraphy, and questionnaires for both oral symptoms and quality of life during the clinical trial. An independent T test or Mann-Whitney U test will be performed to compare values between the two groups. The Paired T test or Wilcoxon signed-rank test will be performed to compare intragroup continuous values.

CONCLUSION

This trial will be significant evidence on the efficacy and safety of combined use of BIT and low-dose pilocarpine to treat intractable xerostomia.

CLINICAL TRIAL REGISTRATION

The Clinical Research Information Service of the Republic of Korea (ISRCTN, KCT0005982). Registered on 10 February 2021.

Mycobiota profile of oral fungal infections in head and neck cancer patients receiving radiotherapy: A 6-year retrospective MALDI-TOF mass spectrometry study

OBJECTIVES

Head and neck cancer (HNC) impairs patient immunity and increases susceptibility to oral fungal infections (OFIs). Effectively treating such infections requires accurate identification of the causative pathogens. This study aimed to characterize the mycobiota profile of OFIs in HNC patients undergoing radiation treatment (RT).

MATERIALS AND METHODS

A 6-year retrospective analysis of oral mucosal samples from HNC patients with a history of RT and OFIs between 2014 and 2019 was conducted using Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) profiling. Samples from the Clinical Microbiology Laboratory at Karolinska University Hospital were evaluated for mycobiota diversity and species co-occurrence patterns in the ongoing-RT and post-RT groups.

RESULTS

A total of 190 oral fungi (88% Candida, 5% Pichia) were isolated from 162 HNC patients receiving RT. In the ongoing-RT group, the emergent non-albicans Candida (NAC) species; F. solani and C. jadinii, were detected for the first time. The dominant pathogens in both ongoing and post-RT groups were C. albicans, C. glabrata, P. kudriavzevii, C. parapsilosis, and C. tropicalis, as shown by Venn analysis. Network analysis revealed greater fungi diversity and multi-species co-occurrence in the ongoing-RT group. C. albicans commonly co-occurred with C. glabrata in both ongoing-RT (21%) and post-RT groups (30%).

CONCLUSION

MALDI-TOF MS identified a wide range of oral fungal species in HNC patients receiving RT. While C. albicans remains the most prevalent OFIs pathogen, multi-species co-occurrence and novel NACs were noted. Understanding the ecological interactions among these causative pathogens could significantly advance the development of effective therapeutics for treating OFIs in HNC patients.

The Role of Host and Fungal Factors in the Commensal-to-Pathogen Transition of Candida albicans

Abstract

Purpose of Review

The fungus Candida albicans has evolved to live in close association with warm-blooded hosts and is found frequently on mucosal surfaces of healthy humans. As an opportunistic pathogen, C. albicans can also cause mucosal and disseminated infections (candidiasis). This review describes the features that differentiate the fungus in the commensal versus pathogenic state and the main factors underlying C. albicans commensal-to-pathogen transition.

Recent Findings

Adhesion, invasion, and tissue damage are critical steps in the infection process. Especially invasion and damage require transcriptional and morphological changes that differentiate C. albicans in the pathogenic from the commensal state. While the commensal-to-pathogen transition has some conserved causes and features in the oral cavity, the female urogenital tract, and the gut, site-specific differences have been identified in recent years.

Summary

This review highlights how specific factors in the different mucosal niches affect development of candidiasis. Recent evidence suggests that colonization of the gut is not only a risk factor for systemic candidiasis but might also provide beneficial effects to the host.

The Role of the Oral Immune System in Oropharyngeal Candidiasis-Facilitated Invasion and Dissemination of Staphylococcus aureus

Candida albicans and Staphylococcus aureus account for most invasive fungal and bacterial bloodstream infections (BSIs), respectively. However, the initial point of invasion responsible for S. aureus BSIs is often unclear. Recently, C. albicans has been proposed to mediate S. aureus invasion of immunocompromised hosts during co-colonization of oral mucosal surfaces. The status of the oral immune system crucially contributes to this process in two distinct ways: firstly, by allowing invasive C. albicans growth during dysfunction of extra-epithelial immunity, and secondly following invasion by some remaining function of intra-epithelial immunity. Immunocompromised individuals at risk of developing invasive oral C. albicans infections could, therefore, also be at risk of contracting concordant S. aureus BSIs. Considering the crucial contribution of both oral immune function and dysfunction, the aim of this review is to provide an overview of relevant aspects of intra and extra-epithelial oral immunity and discuss predominant immune deficiencies expected to facilitate C. albicans induced S. aureus BSIs.

Oral Cavity and Candida albicans: Colonisation to the Development of Infection

Candida colonisation of the oral cavity increases in immunocompromised individuals which leads to the development of oral candidiasis. In addition, host factors such as xerostomia, smoking, oral prostheses, dental caries, diabetes and cancer treatment accelerate the disease process. Candida albicans is the primary causative agent of this infection, owing to its ability to form biofilm and hyphae and to produce hydrolytic enzymes and candialysin. Although mucosal immunity is activated, from the time hyphae-associated toxin is formed by the colonising C. albicans cells, an increased number and virulence of this pathogenic organism collectively leads to infection. Prevention of the development of infection can be achieved by addressing the host physiological factors and habits. For maintenance of oral health, conventional oral hygiene products containing antimicrobial compounds, essential oils and phytochemicals can be considered, these products can maintain the low number of Candida in the oral cavity and reduce their virulence. Vulnerable patients should be educated in order to increase compliance.

Oral and ocular late effects in head and neck cancer patients treated with radiotherapy

A broader understanding of oral and ocular late effects in head and neck cancer (HNC) patients who underwent intensity-modulated radiotherapy (IMRT) may provide valuable information in follow-up and improve quality of life. Twenty-nine HNC patients treated at least 6 months earlier and 30 age-matched controls were recruited. After completing several questionnaires: Oral Health Impact Profile-14 (OHIP-14), Shortened Xerostomia Inventory (SXI), Ocular Surface Disease Index (OSDI) and McMonnies Dry Eye questionnaire (MDEQ), participants underwent oral and ocular examinations. Oral examination included clinical oral dryness score (CODS) and secretion rates of unstimulated and stimulated saliva (UWS, SWS). Ocular examination included tear film break-up time, Schirmer test and ocular surface staining. The patients had more problems related to dry mouth than controls based on CODS and SXI, and more complaints of dry eye disease based on OSDI and MDEQ. UWS and SWS rates and oral health related quality of life were significantly lower in the patient group. Subjective oral dryness (SXI) correlated significantly with subjective ocular dryness (OSDI and MDEQ). Our study demonstrates that HNC patients treated with IMRT experience late effects in terms of xerostomia and ocular dryness underlining the importance of interdisciplinary approach in the evaluation and follow-up of HNC patients.

Candida prevalence in saliva before and after oral cancer treatment

BACKGROUND

Previous studies have shown an increased prevalence of candidiasis in patients receiving radiotherapy for head and neck cancer. However, little is known of the effect the different cancer treatment modalities have on the oral Candida status.

OBJECTIVE AND HYPOTHESIS

The objective of this study was to investigate the change in salivary Candida status of oral squamous cell carcinoma (OSCC) patients undergoing cancer treatment. The hypothesis was that cancer treatments change the oral microbial environment favouring an increase in the prevalence of more pathogenic non-albicans Candida (NAC).

METHODS

We collected paraffin-stimulated saliva from 44 OSCC patients before surgery and after a minimum of 19 months of follow-up. Chromagar, Bichro-Dupli-test and API ID 32 C were used for identification of different Candida species and results were analysed statistically.

RESULTS

At both timepoints, 75% of samples were Candida positive with C. albicans being the most common yeast. NAC strains were present in 16% of the pre-operative samples and 14% of the follow-up samples. The NAC species found were C. dubliniensis, C. krusei, C. guilliermondii (preoperatively only) and C. glabrata (at follow-up only). In 73% of the cases, the salivary Candida status remained unchanged. There was an 18% increase in the prevalence of candidiasis. However, the different treatment modalities did not statistically significantly affect the Candida status of the patients.

CONCLUSION

The intraindividual prevalence of salivary Candida among OSCC patients seems to be stable and different treatment modalities have little to no effect on the salivary Candida status.

Clinical Characteristics and Relevance of Oral Candida Biofilm in Tongue Smears

Dimorphic Candida exist as commensal yeast carriages or infiltrate hyphae in the oral cavity. Here, we investigated the clinical relevance of Candida hyphae in non-pseudomembranous oral candidiasis (OC) by smears of tongue biofilms. We conducted a retrospective study of 2829 patients who had had tongue smears regardless of OC suspicion. Clinical characteristics were evaluated using a novel method of assessing hyphae. Clinical factors (moderate/severe stimulated pain, pain aggravated by stimulation, tongue dorsum appearance and initial topical antifungal use) were highly significant in the high-grade hyphae group but were statistically similar in the low-grade hyphae and non-observed hyphae group, suggesting low-grade hyphae infection as a subclinical OC state. In addition to erythematous candidiasis (EC), a new subtype named "morphologically normal symptomatic candidiasis" (MNSC) with specific pain patterns and normal tongue morphology was identified. MNSC had a significantly higher proportion of moderate and severe stimulated pain cases than EC. Low unstimulated salivary flow rate (<0.1 mL/min) was found to be a common risk factor in MNSC and EC. In non-pseudomembranous OC, pain patterns were dependent on Candida hyphae degree regardless of tongue dorsum morphology. Morphologic differences seen in high-grade hyphae infection were not associated with systemic diseases or nutritional deficiencies.

Candida Infection Associated with Salivary Gland-A Narrative Review

Candida species are common global opportunistic pathogens that could repeatedly and chronically cause oral mucosa infection and create an inflammatory environment, leading to organ dysfunction. Oral Candida infections may cause temporary or permanent damage to salivary glands, resulting in the destruction of acinar cells and the formation of scar tissue. Restricted function of the salivary glands leads to discomfort and diseases of the oral mucosa, such as dry mouth and associated infection. This narrative review attempts to summarize the anatomy and function of salivary glands, the associations between Candida and saliva, the effects of Candida infection on salivary glands, and the treatment strategies. Overall, clinicians should proactively manage Candida infections by educating patients on oral hygiene management for vulnerable populations, conducting frequent checks for a timely diagnosis, and providing an effective treatment plan.

Assessment of saliva and oral candidiasis levels 12, 24 and 36 months after radiotherapy in patients with head and neck cancer

INTRODUCTION

Hyposalivation is a serious complication during radiotherapy (RT) and it is one of the major risk factors for the presence of candidiasis. The aim of this study was to evaluate the salivary hypofunction during the different stages of RT, analysing its connection with the presence of candidiasis.

MATERIAL AND METHODS

A retrospective study was performed in 83 patients who had been diagnosed with head and neck tumours and who were undergoing RT treatment. Their salivary function was clinically analysed throughout the course of the RT treatment (before, during and after treatment) by means of the whole saliva test (WST), both unstimulated (WST-I) and stimulated (WST-II), and its relationship with candidiasis was evaluated using culture-based methods.

RESULTS

The WST-I before RT was 37.24±17.36mm and the WST-II was 60.70±30.98mm, with 47% of patients testing positive for candidiasis. The prevalence of candidiasis increased up to 55.8% during RT and it returned to similar pre-RT levels at the end of treatment (45.2%). A statistical significant relationship was found between low WST-I and candidiasis in the 1st (13.58 vs 20.78mm), 3rd (18.06 vs 24.36mm), 6th (16.83 vs 24.5) and 12th (16 vs 28.74mm) months after RT; and this relationship was also detected for WST-II in the 1st (24.73 vs 41.26mm) and 3rd (27.71 vs 39.91mm) months after RT. Female sex was identified as an independent associated risk factor for mild hyposalivation before RT (OR=6.50, CI: 95% 1.77-23.93, p=0.005) and glandular hypofunction (OR=3.01, CI: 95% 1.12-8.10, p=0.029).

DISCUSSION

There is a clear relation between hyposalivation and the presence of candidiasis during and after RT. Larger studies must be performed in order to further elucidate this effect.

Efficacy of gel-based artificial saliva on Candida colonization and saliva properties in xerostomic post-radiotherapy head and neck cancer patients: a randomized controlled trial

Objective

To evaluate the efficacy of an edible artificial saliva gel, oral moisturizing jelly (OMJ), and a topical commercial gel (GC dry mouth gel) on Candida colonization and saliva properties.

Materials and methods

This study was a secondary analysis of a single-blinded randomized controlled trial conducted in xerostomic post-radiotherapy head and neck cancer patients. Candida colonization, stimulated salivary flow rate (SSFR), saliva pH, and buffering capacity (BC) were measured at 0, 1, and 2 months after each intervention. Candida colonization was quantified by colony counts and species identified by Candida Chromagar, polymerase chain reaction, and API 20C AUX system. Statistical significance level was 0.05.

Results

A total of 56 participants in OMJ (N = 30) and GC (N = 26) groups completed the study. OMJ significantly increased saliva pH (p = 0.042) and BC (p = 0.013) after 1-month use, while GC only improved saliva pH (p = 0.027). Both interventions tended to increase SSFR but only GC had a significant increase at 2 months (p = 0.015). GC and OMJ significantly decreased the number of Candida species at 1 and 2 months, respectively. Both groups tended to reduce Candida counts but not significant.

Conclusions

Both OMJ and GC saliva gels could improve saliva pH and decrease the number of Candida species. OMJ is superior to GC in its buffering capacity, while GC may better improve salivary flow rate. Long-term and large-scale study is warranted to test the efficacy of artificial saliva in oral health improvement.

Clinical relevance

OMJ and GC gel could decrease the number of Candida species and improve saliva properties in post-radiation xerostomic patients.

Trial registration number

Clinicaltrials.gov NCT03035825. Date of registration: 25th January 2017.

Late Oral Complications Caused by Head and Neck Radiotherapy: Clinical and Laboratory Study

Objectives

The aim of presented cross-sectional and observational study was to determine the prevalence of late oral complications of patients with head and neck cancer who underwent radiotherapy, by clinical and laboratory analyses.

Material and Methods

Fifty-five patients, 43 (78.2%) men and 12 (21.8%) women, mean age 60; range 38 to 87 years, who have completed radiotherapy for head and neck cancer for at least 6 months were enrolled. The presence of xerostomia, hyposalivation, oral candidiasis, and type of oral yeasts were correlated with post-radiotherapy period. A control group, age and gender matched, was used for comparisons. The Pearson’s Chi-square or Fischer’s exact test was used at a significance level of 5%.

Results

The mean post-radiotherapy period was 32 months. The oral complications found were xerostomia (45/55, [81.8%]), hyposalivation (44/55 [80%]) and oral candidiasis (15/55 [27.2%]). Xerostomia and hyposalivation was statistically higher in the study group when compared to the control group (P < 0.05). The presence of yeast occurred in 39 (70.9%) of the patients in the study group, and Candida albicans was the most prevalent etiological agent in 25 (64.1%) of those patients (P < 0.05).

Conclusions

Xerostomia and hyposalivation were the more prevalent late oral complications related to radiotherapy. Oral candidiasis was also observed, although its prevalence was lower. The need for long-term dental follow-up of patients who underwent radiotherapy of the head and neck cancer is mandatory.

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.

Oral Candida colonization in xerostomic postradiotherapy head and neck cancer patients

OBJECTIVES

To evaluate (a) oral colonization of Candida species, especially for non-albicans Candida species (NACS), in xerostomic postradiotherapy head and neck cancer patients and (b) risk factors affecting their colonization.

MATERIALS AND METHODS

Subjective and objective dry mouth scores, stimulated salivary flow rates, pH and buffering capacity were measured in 72 xerostomic postradiotherapy head and neck cancer patients. Candida counts and species identification were performed using oral rinse samples cultured in Candida Chromagar, followed by polymerase chain reaction and API 20C AUX system.

RESULTS

Candida colonization was observed in 87.5% of subjects, with 80.6% and 48.6% of study population colonized by C. albicans and NACS, respectively. NACS was associated with high objective dry mouth scores, denture use, and females (p = .006, .009, and .036, respectively). In addition, Candida glabrata was detected more in females (p = .018) and denture wearers (p = .026), while Candida tropicalis was associated with high objective dry mouth scores (p = .022) and females (p = .027). Quantity of Candida colonization correlated positively with objective dry mouth scores (r = 0.599, p < .001) and negatively with salivary flow rates (r = -0.258, p = .041) and pH (r = -0.290, p = .022).

CONCLUSION

NACS colonization was common in xerostomic head and neck cancer patients. Increased signs of dry mouth, female and dental prostheses may promote NACS colonization.

Change of saliva composition with radiotherapy

OBJECTIVE

The aim of this study was to analyze the physiological and microbiological changes of saliva from patients with head and neck cancer during and after intensity-modulated radiotherapy (IMRT).

DESIGN

In this prospective clinical trial saliva samples and oral candida swabs were collected from patients receiving IMRT due to head and neck cancer (examination group). The first measurement was scheduled before radiotherapy, the other measurements during and after radiotherapy up to a one year follow-up. Additionally samples from healthy controls were collected over six weeks. Salivary flow rate and pH were measured. Microbiological analysis of cariogenic and periodontopathogenic taxa was performed by fluorescence in situ hybridization and oral Candida spp occurrence was evaluated by swab tests.

RESULTS

11 patients and 19 controls were included. The salivary flow rate and the unstimulated pH of the examination group were significantly reduced during radiotherapy compared with the measurement before radiotherapy and to the control group. Total bacteria, streptococci and lactobacilli numbers slightly increased after radiotherapy, resuming baseline levels after one year. Mutans streptococci, Porphyromonas gingivalis and Treponema denticola were barely detectable, whereas Tannerella forsythia slightly increased following radiotherapy. No differences in Candida levels were observed in the study.

CONCLUSIONS

Salivary changes in quantitative, qualitative and microbial composition occur during and after radiotherapy, with resumption of the measurements towards baseline levels after one year. While low levels of cariogenic and periodontopathogenic species were detected, the lower pH and salivary flow combined with increased numbers of aciduric and acidogenic lactobacilli corroborates a higher risk for caries, necessitating prevention.

A retrospective study of factors associated with the development of oral candidiasis in patients receiving radiotherapy for head and neck cancer: Is topical steroid therapy a risk factor for oral candidiasis?

The aims of this study were to investigate the incidence and risk factors for oral candidiasis in patients receiving radiotherapy for head and neck cancer, and to determine the influence of topical steroid therapy on the development of oral candidiasis.We conducted a retrospective study of 300 patients receiving radiotherapy to the head and neck region. The primary endpoint was the incidence of oral candidiasis during radiotherapy. Associations between the incidence of oral candidiasis and various clinical factors were investigated. The cumulative incidence rate of oral candidiasis was calculated using the Kaplan-Meier method and analyzed by the log-rank test and Cox regression. Propensity score-matched analysis was used to assess the influence of topical steroid therapy on the development of oral candidiasis.Oral candidiasis occurred in 75 (25.0%) of the 300 patients. Multivariate analysis identified minimum lymphocyte count and severity of oral mucositis during radiotherapy as independent risk factors for the development of oral candidiasis. Topical steroid therapy for oral mucositis was not associated with the incidence of oral candidiasis according to multivariate and propensity score matching analyses.Oral candidiasis was associated with the suppression of the host's immunity and severe oral mucositis, but not topical steroid therapy. Proper oral health care during radiotherapy and the prevention of severe oral mucositis may reduce the incidence of oral candidiasis.

Esophagitis associated with multimodality management of pediatric Ewing sarcoma of thorax

BACKGROUND

Ewing sarcoma of the thoracic spine and chest wall is frequently treated with concurrent chemotherapy and radiation therapy (RT). Treatment-related acute esophagitis can lead to hospitalization and treatment delays. The aim of this study was to analyze the incidence, risk factors, and management of esophagitis in pediatric patients with Ewing sarcoma of the thoracic region.

METHODS

We conducted a single-institution retrospective review of patients treated over a 10-year period. Medical records were reviewed for patient and treatment characteristics associated with Common Terminology Criteria for Adverse Events grade 2 or higher esophagitis. RT plans were also reviewed and various esophageal dose metrics were analyzed.

RESULTS

Twelve of 37 patients (32%) developed acute esophagitis. Neutropenia was associated with an increased risk of esophagitis (60% vs. 14%; P < 0.01). RT significantly contributed to its incidence when maximum esophageal dose was >47 Gy (69% vs. 5%; P < 0.0001) and esophageal D5cm³ was >15 Gy (67% vs. 9%; P < 0.001). All 12 patients with esophagitis were managed with oral opioid analgesics. Nine patients with persistent symptoms received subsequent fluconazole for empiric fungal treatment and each had a decreased need for opioid analgesics within 2-5 days.

CONCLUSION

Approximately one-third of patients with Ewing sarcoma of the thoracic region will develop acute esophagitis. An esophageal D5cm³ dose < 15 Gy and maximal esophageal dose < 47 Gy may keep the rate of acute esophagitis under 5%. However, the association with neutropenia and consistent response to antifungal therapy suggest chemotherapy-associated toxicity and an infectious component as part of the process.

Mucosal microflora in head and neck cancer patients

OBJECTIVE

To analyse the tongue and buccal microflora prospectively in head and neck cancer patients treated with radiation therapy (RT).

METHODS

In 33 dentate patients, microbial samples from the tongue and buccal mucosa were collected pretreatment, during treatment, and 6 months, 1 year and 2 years post-treatment. Microorganisms associated with oral health and oral disorders were analysed using cultivation technique. Oral mucositis was scored at the appointment during treatment.

RESULTS

Compared with pretreatment, lactobacilli and Candida increased on the tongue, while streptococci and Neisseria decreased during treatment. Two years post-treatment, Neisseria and Prevotella were decreased and Candida increased. On the buccal mucosa, an increased growth of lactobacilli and increased detection frequencies of the opportunistic bacteria Staphylococcus aureus, Gram-negative enteric rods and enterococci were seen during treatment compared with pretreatment. Seventy per cent showed severe mucositis during treatment. Two years post-treatment the total count as well as streptococci, Neisseria and Fusobacterium nucleatum were decreased and lactobacilli increased compared with pretreatment.

CONCLUSION

Despite improvements in treatment for cancer in the head and neck region, microorganisms associated with oral health decrease during treatment and mucosal pathogens increase. Two years post-treatment, levels of acid-tolerant (lactobacilli and Candida) were increased, while acid-sensitive microorganisms (Neisseria and F. nucleatum) were decreased, plausibly due to persisting decreased salivary secretion rate.

γ-irradiation from radiotherapy improves the virulence potential of Candida tropicalis

AIM

To evaluate if radiation used in radiotherapy can cause changes in the virulence potential of Candida tropicalis ATCC 750.

MATERIALS & METHODS

C. tropicalis was exposed in vitro to identical dose and scheme of irradiation would be used in patients with head and neck cancer. Some virulence parameters were analyzed before and after irradiation.

RESULTS

Colony morphologies were irreversibly affected by irradiation. Increase in growth rate, filamentation, adhesion on cell lines and phagocytosis process were also observed. Overall the irradiated C. tropicalis cells became more efficient at causing systemic infection in mice.

CONCLUSION

γ-radiation induced important changes in C. tropicalis increasing its virulence profile, which could directly affect the relationship between yeasts and hosts.

In Vitro Evaluation of the Inhibitory Activity of Thymoquinone in Combatting Candida albicans in Denture Stomatitis Prevention

Candida albicans adhesion and proliferation on denture bases may lead to denture stomatitis, which is a common and recurrent problem in denture wearers. The goal of this study was to assess the inhibitory effect of thymoquinone incorporated in the polymethyl methacrylate denture base material against Candida albicans. Eighty acrylic resin specimens were fabricated and divided into eight groups (n = 10) according to thymoquinone concentrations of 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, and 5% of acrylic powder. Two methods were used to evaluate the effect of thymoquinone on Candida albicans: the slide count and the serial dilution test. A multivariate analysis of variance (MANOVA) and the post-hoc Tukey’s Honestly Significant Difference (HSD) test were performed to compare the difference of means between the observations taken at various intervals with baseline. The p value was statistically significant at ≤0.05. According to the slide count and the serial dilution test, the mean number of adhered Candida albicans in the control group was 5436.9 ± 266 and 4691.4 ± 176.8; however, this number dramatically decreased to 0 ± 0 and 32.4 ± 1.7 in group 8 (concentration 5%). These results suggest that the incorporation of thymoquinone into the acrylic resin denture base material might be effective in preventing Candida albicans adhesion.

Original Research. Candida in Oral and Maxillofacial Pathology: Clinical Findings and Risk Factors

Background: Candida, and especially Candida albicans, colonizes the oral mucosa and becomes invasive when the immune system weakens. Therefore, frequently, oral and maxillofacial pathology can be associated with Candida. Objective: The qualitative and quantitative assessment of Candida colonization of the oral cavity in patients with oro-maxillo-facial conditions; to establish an association between the different contributing factors and colonization. Material and methods: Samples were collected from 70 patients hospitalized in the Clinic of Oral and Maxillo-Facial Surgery, by rinsing the mouth with sterile saline; historical data were also collected. The samples were analyzed at the Microbiology Laboratory of the University of Medicine and Pharmacy of Tîrgu Mureș, using Sabouraud agar medium. For each isolate, the antifungigram for Fluconazole and Voriconazole was performed following the CLSI standards. Results: From the 70 samples 45.7% were positive for 11 different yeast species. Regarding predisposing factors, most importantly, smoking was significantly associated with Candida colonization (OR = 2.34; 95% CI = 1.42-3.84; p <0.05). Other factors, such as radiotherapy, oral hygiene or antibiotics, are related, but not statistically significant in our study. Candida albicans was the predominant species (38.8%). The testing of Candida albicans and non-albicans to Fluconazole showed an increased resistance (52.4%) in both cases, while the resistance to Voriconazole was 50% and 12.5%, respectively. Conclusions: Colonization of the oral cavity with Candida is present in about half of the patients with OMF conditions, and this is probably not only due to classical predisposing factors, but also due to chronic oral pathology and to several risk factors like smoking or radiotherapy.

Facilitated saliva secretion and reduced oral inflammation by a novel artificial saliva system in the treatment of salivary hypofunction

Saliva substitutes and/or lubricants are commonly employed to lessen dry mouth symptoms by stimulating and/or substituting for the secretion of saliva. In this study, a novel artificial saliva containing inorganic salts, including sodium chloride and potassium chloride, and bactericidal agents, including potassium thiocyanate and lactoperoxidase, was formulated in the form of a solution (DM-sol) or gel (DM-gel). Those in vivo therapeutic efficacies were assessed in terms of saliva secretion and anti-inflammatory activity in rats and mice, respectively. Salivary secretion was promoted by mucosal application of DM-formulations in normal rats. In particular, DM-gel resulted in 2.5- and 1.9-fold greater salivary flow rates compared to normal saline and DM-sol, respectively. In an in vivo efficacy evaluation in diabetic mice with salivary hypofunction, repeated application of DM-formulations alleviated histopathological changes in the buccal mucosa in terms of atrophy and thinning of the epithelium, compared to vehicle, after 4 weeks. Moreover, the DM-sol and DM-gel were comparably effective for relieving periodontal gingivitis, reducing infiltration of inflammatory cells, and normalizing the neutrophil level in the gingival gingiva, after 4 weeks. Therefore, the novel artificial saliva is expected to facilitate salivary secretion and restore physiological conditions in the mouth of patients with salivary hypofunction.

Managing xerostomia and salivary gland hypofunction: executive summary of a report from the American Dental Association Council on Scientific Affairs

BACKGROUND AND OVERVIEW

Xerostomia, also known as "dry mouth," is a common but frequently overlooked condition that is typically associated with salivary gland hypofunction, which is the objective measurement of reduced salivary flow. Patients with dry mouth exhibit symptoms of variable severity that are commonly attributed to medication use, chronic disease and medical treatment, such as radiotherapy to the head and neck region. Chronic xerostomia significantly increases the risk of experiencing dental caries, demineralization, tooth sensitivity, candidiasis and other oral diseases that may affect quality of life negatively. This article presents a multidisciplinary approach to the clinical management of xerostomia, consistent with the findings of published systematic reviews on this key clinical issue.

CONCLUSIONS AND PRACTICE IMPLICATIONS

Initial evaluation of patients with dry mouth should include a detailed health history to facilitate early detection and identify underlying causes. Comprehensive evaluation, diagnostic testing and periodic assessment of salivary flow, followed by corrective actions, may help prevent significant oral disease. A systematic approach to xerostomia management can facilitate interdisciplinary patient care, including collaboration with physicians regarding systemic conditions and medication use. Comprehensive management of xerostomia and hyposalivation should emphasize patient education and lifestyle modifications. It also should focus on various palliative and preventive measures, including pharmacological treatment with salivary stimulants, topical fluoride interventions and the use of sugar-free chewing gum to relieve dry-mouth symptoms and improve the patient's quality of life.

Evaluation of oral prophylaxis during and after intensity-modulated radiotherapy due to head and neck cancer--a retrospective study

OBJECTIVES

The aim of this study was to retrospectively analyze the influence of a prophylaxis protocol of head and neck tumor (HNT) patients during and after intensity-modulated radiotherapy (IMRT).

MATERIAL AND METHOD

In this 5-year retrospective study (2009-2013), 70 (m 55, f 15; age range 28-8 years; median 58.7 years) out of 248 HNT patients of the Clinic of Cranio-Maxillofacial and Oral Surgery at the University of Zurich, Switzerland, fulfilled the inclusion criteria. Parameters of investigation were the salivary flow rates, possible dental foci and the dental status, oral side effects of radiotherapy, the prophylaxis protocol, and patient's compliance to this protocol. The following time points before during and after IMRT (6 weeks) were analyzed: prior to IMRT, 2-4 weeks, 6 weeks and 3, 6, and 12 months after the onset of radiotherapy.

RESULT

Unstimulated salivary flow rate, pH value of unstimulated salivary, and stimulated salivary flow rate showed a significant reduction over time (p < 0.001). One year after IMRT, both unstimulated and stimulated salivary flow showed a statistically significant lower salivary flow. The number of caries-affected sites per patient was significantly higher for patients with low compliance to the prophylaxis protocol (mean: low compliance 1.36, high compliance 0.26). Almost 75% of the evaluated patients suffered immediate gustatory change, and 47.1% showed signs of radiostomatitis through IMRT.

CONCLUSIONS

High compliance to the prophylaxis protocol during and after radiotherapy is a key factor for the reduction of radiation side effects on dental hard tissue.

CLINICAL RELEVANCE

High compliance to a monitored prophylaxis program is crucial for patients after head and neck surgery.

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.

Antifungal Susceptibility In Vitro Determined by the Etest(r) for Candida Obtained from the Oral Cavity of Irradiated and Elderly Individuals

This study aimed to evaluate the in vitro antifungal susceptibility of Candida species of head-and-neck-irradiated patients (Group 1), non-institutionalized (Group 2) and institutionalized elders (Group 3) using Etest(r) methodology. Candida was isolated from saliva and presumptively identified by CHROMagar Candida(r), confirmed by morphological criteria, carbohydrate assimilation (API 20C AUX(r)) and genetic typing (OPE 18). The collection was made from 29, 34 and 29 individuals (Groups 1, 2 and 3, respectively) with 67 isolates. Etest(r) strips (ketoconazole, itraconazole, fluconazole, amphotericin B and flucytosine) on RPMI (Roswell Park Memorial Institute) agar, on duplicate, were used to evaluate susceptibility. ATTC (American Type Culture Collection) 10231 (Candida albicans) was used as quality control. Among the 67 isolates of Candida species, most were susceptible to azoles, flucytosine and amphotericin B. None of the isolates showed resistance and dose-dependent susceptibility to amphotericin B. There were nine strains resistant to itraconazole, six to fluconazole and two to ketoconazole and ten dose-dependent, mainly to flucytocine. The highest MIC (minimum inhibitory concentration) to C. albicans, C. tropicalis, C. parapsilosis was 2.671 μg.mL-1, 8.104 μg.mL-1, 4.429 μg.mL-1, all for flucytosine. C. krusei and C. glabrata were associated with higher MIC for azoles and C. glabrata with higher MIC to flucytosine. In summary, susceptibility to all tested antifungal agents was evident. The isolates were more resistant to itraconazole and dose-dependent to flucytosine. A comparison of C. albicans in the three groups showed no outliers. Higher MIC was associated with C. krusei and C. glabrata.

The impact of dairy consumption on salivary inoculum

Quantitative levels of harmful oral microbes present following complex surgical excisions of head and neck cancer are important since wounds are often contaminated through direct connection to the oral cavity and its flora. This possibility is especially important in irradiated patients who have decreased protective salivary function. In addition, high oral microbial levels increase and intensify oral mucositis leading to significant morbidity in patients treated with radiation therapy. One previously untested surgical teaching to decrease the bacterial inoculum present in the oral cavity is to counsel patients against consuming otherwise nutritious dairy products, as they are thought to coat the oral cavity with rate-limiting nutrients vital for bacterial growth. This risk may extend to individuals with chronic laryngeal penetration or aspiration, since salivary bacterial load might represent a lethal threat in the presence of marginal pulmonary reserve. A crossover study using six healthy adult volunteers and six patients who had previously undergone radiation therapy to an oropharyngeal primary site was performed. Saliva samples were quantitatively cultured in both groups with and without the consumption of dairy products at 1-h and 5-h intervals. Analysis of quantitative cultures demonstrated that the consumption of dairy products had no influence on bacterial levels present in previously radiated subjects and nonirradiated controls. Additionally, the consumption of dairy did not affect the composition of microbes present. Due to the lack of changes in both quantity and composition of oral bacteria seen in this study, patients would not benefit from the avoidance of dairy products.

The influence of parotid gland sparing on radiation damages of dental hard tissues

OBJECTIVE

The aim of the present study was to evaluate whether radiation damage on dental hard tissue depends on the mean irradiation dose the spared parotid gland is subjected to or on stimulated whole salivary flow rate.

MATERIAL AND METHODS

Between June 2002 and October 2008, 70 patients with neck and cancer curatively irradiated were included in this study. All patients underwent dental treatment referring to the guidelines and recommendations of the German Society of Dental, Oral and Craniomandibular Sciences prior, during, and after radiotherapy (RT). During the follow-up period of 24 months, damages on dental hard tissues were classified according to the RTOG/EORTC guidelines. The mean doses (D(mean)) during spared parotid gland RT were determined. Stimulated whole saliva secretion flow rates (SFR) were measured before RT and 1, 6, 12, 24 months after RT.

RESULTS

Thirty patients showed no carious lesions (group A), 18 patients developed sporadic carious lesions (group B), and 22 patients developed general carious lesions (group C). Group A patients received a D mean of 21.2 ± 11.04 Gy. Group B patients received a D(mean) of 26.5 ± 11.59 Gy and group C patients received a D(mean) of 33.9 ± 9.93 Gy, respectively. The D(mean) of group A was significantly lower than the D(mean) of group C (p < 0.001). Additionally, the mean SFR 6 months after RT of group A was significantly higher than the mean SFR of group C (p < 0.01).

CONCLUSIONS

Irradiation damage on dental hard tissue correlates with increased mean irradiation doses as well as decreased salivary flow rates.

CLINICAL RELEVANCE

Parotid gland sparing resulting in a dose below 20 Gy reduces radiation damage on dental hard tissues, and therefore, the dose may act as a predictor for the damage to be expected.