Oropharyngeal candidosis relative frequency in radiotherapy patient for head and neck cancer

Might photobiomodulation therapy interfere with the frequency of severe mucositis and oral candidiasis? A retrospective analysis in patients with head and neck carcinoma

PURPOSE

Considering the tumor in the oral cavity or the oropharynx and nasopharynx region might be an aggravating factor for oral mucositis (OM) manifestation, the present study aimed to evaluate whether the location of the tumor and the use of photobiomodulation therapy (PBMT) might affect the frequency of oral candidiasis (OC) during radiotherapy (RT) and/or chemotherapy (CT) treatments.

METHODS

The medial records of seventy-four patients with head and neck cancer treated in a public service from 2016 to 2019 were evaluated. All these patients were submitted to RT in an accumulated dose of 48 to 70 Gy of radiation. Data about OM and OC were collected and presented according to the application of a therapeutic protocol with laser photobiomodulation (PBMT) to control oral mucositis, or not (No-PBM), and the location of tumor (head and neck or oral cavity). In the PBMT group patients, a low-power laser device composed of InGaAlP diode (maximum output power of 86.7 mW, active tip area of 0.1256 cm2, and continuous wavelength of 660 nm), was applied to the lips (three points each), right and left jugal mucosa (three points each), the limit between hard and soft palate (three points), buccal floor/sublingual gland (one point), lateral edge of the tongue (three points on each side), and back of the tongue (six points), three times weekly, for 5 weeks. The dosimetry used in each application was 2 J for 3 s, thus totaling 56 J. The correlation between clinical characteristics such as age, tumor size (T), metastatic lymph node (N), number of RT and CT sessions, candidiasis, and OM were analyzed.

RESULTS

Mucositis grades 1 and 2 were the most common among all patients, especially before the 12th radiotherapy session, regardless of the treatment with PBM (p > 0.05). Additionally, no difference in the grade of OM and OC was significantly observed when comparing the two laser therapy groups. OC was more frequent after the 12th radiotherapy session in all groups. Nonetheless, OM and OC had a different correlation regarding to tumor location (head and neck and oral cavity) being PBMT a positive therapy to delay OM. It was observed a positive and statistically significant correlation between tumors at oral cavity and OM, regardless PBMT (R = 0.84, p < 0.05 to PBMT and R = 0.13, p < 0.05 to No-PBM). Otherwise, OC was positively correlated to local metastasis in patients with oral tumors undergoing PBMT (R = 0.84, p < 0.05).

CONCLUSION

Patients with oral cavity tumor presented more OM, especially high grades, then patients with tumors in other regions of the head and neck, which seems to be related to the irradiation parameters of radiotherapy and/or with the limitation of conduction of PBMT in tumor areas. OM and OC were not changed by PBMT, although it helped to reduce the incidence of severe cases of OM.

Molecular mechanisms of azole resistance in Candida glabrata isolated from oropharyngeal candidiasis in head and neck cancer patients

OBJECTIVE

The aim of the current work was to assess the molecular mechanisms of fluconazole-resistant Candida glabrata strains isolated from oropharyngeal candidiasis (OPC) in head and neck patients, as well as evaluation of virulence factors.

DESIGN

Antifungal susceptibility pattern of sixty six clinical isolates of C. glabrata were evaluated by broth-microdilution method. The expression of ERG11, CDR1, CDR2, PDR1 genes as well as ERG11 gene capable of possible mutations was also detected in 21 fluconazol-resistant C. glabrata isolates. Phospholipase and proteinase activity of these isolates was estimated, too. The correlation between the virulence factors, antifungal susceptibility patterns and cancer type was also analyzed.

RESULTS

Seven synonymous and four non-synonymous mutations were found in 21 fluconazole-resistant C. glabrata isolates; subsequently, four amino acid substitutions including H257P, Q47H, S487Y and I285N were then reported for the first time. High expression of CDR1 and PDR1 in related to other gene findings were tested in these isolates. Additionally, there was no significant difference between stage of cancer and MIC of all antimicrobial drugs. Significant differences between MIC of fluconazole, voriconazole and cancer types were also, found. The proteinase activity (92.4%) was higher than phospholipase activity in the isolates. Further, no significant difference between proteinase (rs: 0.003), phospholipase (rs: -0.107) activity and fluconazole MICs was observed.

CONCLUSION

C. glabrata isolated from OPC in head and neck patients represented high capacities for proteolytic enzymes activity and high mRNA level of CDR1 and PDR1 gene and ERG11 mutations play an important role in azole drug resistance.

Comparison of oral candidiasis characteristics in head-and-neck cancer patients before and during radiotherapy

Background

Patients undergoing head-and-neck radiotherapy are susceptible to Candida colonization and infection. This study aimed to identify oral Candida species type (ST), colony count (CC), and oropharyngeal candidiasis (OPC) in head-and-neck cancer patients, undergoing radiotherapy, before and 2 weeks after radiation.

Materials and Methods

In this quasi-experimental study, head-and-neck cancer patients undergoing radiotherapy (up to 6000 cGy) were recruited. Samples were taken before and 2 weeks after radiation therapy (RT). CC was assigned using Sabouraud dextrose agar culture medium and morphological studies were performed to confirm OPC. For identification, polymerase chain reaction-restriction fragment length polymorphism was performed. Data were analyzed using Chi-square-test and kappa coefficient. P < 0.05 was considered statistically significant.

Results

Twenty-one of 33 patients were Candida positive. The detected fungal species included Candida albicans (60%), Candida tropicalis (22%), Candida glabrata (9%), and other species (9%). Following RT, OPC and CC changed significantly (P = 0.003 and P = 0.001, respectively), whereas ST did not significantly change (P = 0.081). Two new species (Candida krusei and Candida parapsilosis) were detected after the intervention. The OPC, CC, and ST changes after RT were not significantly related to malignancy site or radiation dose (P > 0.05).

Conclusion

The present study showed that OPC, CC, and ST were not related to the malignancy site. Following RT, OPC and CC changed significantly, while ST showed no significant change. The radiation dose and malignancy site had no effects on the OPC, CC, or ST alterations following RT.

Azole Resistance in Candida albicans Isolates from Oropharyngeal Candidiasis is Associated with ERG11 Mutation and Efflux Overexpression

Background: Azole resistance rates are rising in Candida species. Fluconazole is one of the most important antifungal drugs used in candidiasis treatment. Objectives: We identified the molecular mechanisms of fluconazole resistance of Candida albicans oropharyngeal candidiasis (OPC) isolates obtained from head and neck cancer patients, a study carried out between 2018 and 2020. Methods: One hundred and twenty-five Candida albicans clinical isolates were collected. Antifungal susceptibilities were determined by the CLSI- M27-A3 method. The ERG11 gene was amplified and sequenced to discover SNP mutation. Moreover, real-time PCR was carried out to measure the mRNA levels of ERG11, CDR1, CDR2, and MDR1. Results: Resistance to fluconazole was found in 15 C. albicans isolates. Amino acid substitutions E266D and D116E were observed in resistant, sensitive dose-dependent (SDD), and susceptible C. albicans isolates. K128T, G465S, A114S, Y257H and V488I were in relation to fluconazole resistance. D504A, P375A, W520C, G59S, and V51L were novel substitutions detected in the isolates; except for D504A, other mutations were observed only in resistance isolates. The expression levels of CDR2, CDR1, MDR1, and ERG11 were increased compared to susceptible isolates, respectively. Conclusions: ERG11 mutation was the principal mechanism for fluconazole resistance in C. albicans isolated from oropharyngeal candidiasis patients, and caspofungin can be used as the effective antifungal substance in fluconazole resistance situation for C. albicans infection.

Oral Candida spp. Colonisation Is a Risk Factor for Severe Oral Mucositis in Patients Undergoing Radiotherapy for Head & Neck Cancer: Results from a Multidisciplinary Mono-Institutional Prospective Observational Study

Simple Summary

This study aims to find a correlation between Candida spp. oral colonisation prior to radiotherapy and (i) the development of severe oral mucositis (OM) (grade 3/4) and (ii) early development of severe OM (EOM). Candida spp. in the oral cavity appears to be a predictive factor of EOM. Preventive treatment could aid in reducing incidence of EOM. Further clinical trials are required to confirm our findings.

Abstract

Background: This study aims to find a correlation between Candida spp. oral colonisation prior to radiotherapy (RT) and (i) the development of severe oral mucositis (OM) (grade 3/4) and (ii) early development of severe OM (EOM). Methods: The protocol was registered on ClinicalTrials.gov (ID: NCT04009161) and approved by the ethical committee of the ‘Fondazione Policlinico Universitario Gemelli IRCCS’ (22858/18). An oral swab was obtained before RT to assess the presence of Candida spp. Severe OM occurring before a dose of 40 Gy was defined as EOM. Results: No patient developed G4 OM, and only 36/152 patients (23.7%) developed G3 OM. Tumour site and lymphocytopenia were risk factors for severe OM (OR for tumour site: 1.29, 95% CI: 1–1.67, p = 0.05; OR for lymphocytopenia: 8.2, 95% CI: 1.2–55.8, p = 0.03). We found a correlation between Candida spp. and EOM (OR: 5.13; 95% CI: 1.23–21.4 p = 0.04). Patients with oral colonisation of Candida spp. developed severe OM at a mean dose of 38.3 Gy (range: 28–58; SD: 7.6), while negative patients did so at a mean dose of 45.6 Gy (range: 30–66; SD: 11.1). Conclusions: Candida spp. in the oral cavity appears to be a predictive factor of EOM.

A preliminary study of suppression of candida infection by miconazole mucoadhesive tablets in oral or oropharyngeal cancer patients undergoing radiotherapy

Elevated numbers of candida in the oral cavity often lead to oral candidiasis development in patients undergoing radiotherapy for oral or oropharyngeal cancer. This study aimed to verify the effect of miconazole mucoadhesive tablets on suppression of oral candida infection during radiotherapy. For this preliminary interventional study, miconazole mucoadhesive tablets were attached to the oral mucosa for 14 days from when grade 2 oral mucositis appeared in patients with oral or oropharyngeal cancer receiving radiotherapy, and the incidence of oral candidiasis was investigated. Various clinical factors were examined; univariate and multivariate Cox regression analyses were performed to investigate and compare the efficacy of this drug in preventing oral candidiasis with results of our previous study as historical control. Miconazole mucoadhesive tablets were administered to 18 patients, and oral candidiasis was observed in one patient (5.6%) after treatment completion. Among 144 historical control patients, 43 (29.9%) developed oral candidiasis. Multivariate Cox regression showed that miconazole mucoadhesive tablets significantly reduced oral candidiasis development during radiotherapy (p = 0.049, Hazard ratio 0.136, 95% confidence interval 0.019–0.994). This preliminary study suggests the efficacy of miconazole mucoadhesive tablets in preventing oral candidiasis in oral or oropharyngeal cancer patients treated with radiotherapy.

Trial registration: Japan Registry of Clinical Trials (jRCT), jRCTs071190023. Registered 3 September, 2019.

Species Diversity and Antifungal Susceptibilities of Oral Yeasts from Patients with Head and Neck Cancer

Purpose

To investigate the colonization and susceptibility to antifungal drugs of oral yeasts in head and neck cancer patients in Hainan, China.

Methods

Oral mucosa samples from 211 head and neck cancer patients were collected. Oral yeasts were isolated and identified to species by rDNA ITS sequencing. The susceptibilities of all yeasts to amphotericin B, fluconazole, fluorocytosine, itraconazole, and ketoconazole were determined.

Results

Yeasts were isolated from 124 of the 211 oral swabs. The 124 yeast isolates were classified into following 10 species, from the most frequent to the least frequent, Candida albicans (53.2%), Candida tropicalis (22.6%), Candida krusei (6.5%), Kodamaea ohmeri (5.6%), Candida parapsilosis (4.8%), Hanseniaspora opuntiae (2.4%), Candida metapsilosis (1.6%), Pichia terricola (1.6%), Pichia norvegensis (0.8%), and Trichosporon asahii (0.8%). The overall frequencies of resistance among the yeasts to amphotericin B, fluconazole, flucytosine, itraconazole, and ketoconazole were 4.8%, 8.1%, 16.1%, 9.7%, and 9.7%, respectively. One C. albicans strain and one C. tropicalis strain were tolerant/resistant to all five drugs.

Conclusion

Given the high prevalence of oral yeast colonization in head and neck cancer patients and the observed resistance of certain yeast isolates to the five antifungal drugs, our results suggest that rapid identification and susceptibility testing should be implemented before antifungal treatment is applied among patients with head and neck cancer in Hainan.

Aspartyl Proteinase and Phospholipase Activities of Candida albicans Isolated From Oropharyngeal Candidiasis in Head and Neck Cancer Patients

Background: Candida albicans is one of the most important members of the human normal flora that can cause opportunistic fungal infections. Hydrolytic enzymes are one of the main virulence factors in the pathogenesis of Candida species. Objectives: This study was carried out to determine proteolytic activities, and their related gene expressions in C. albicans isolates obtained from oropharyngeal candidiasis in head and neck cancer patients. Methods: Thirty-two C. albicans clinical isolates were included in this study. Secreted aspartyl protease and phospholipase activities were analyzed by appropriate agar media and precipitation zones. The expression levels of SAP1, 3 and PLB1, 2 genes were evaluated by real-time PCR. Results: All the 32 isolates exhibited proteinase activity while 28 of them showed phospholipase activity. All the strains possessed all SAPs genes; however, PLBs genes were not expressed in four isolates. Conclusions: Our findings demonstrated that the clinical strains of C. albicans had strong proteolytic activity and high expression levels of the pertaining genes.

Oropharyngeal candidiasis in head and neck cancer patients in Iran: Species identification, antifungal susceptibility and pathogenic characterization

OBJECTIVE

Oropharyngeal candidiasis (OPC) is the most frequent opportunistic fungal infection in head and neck cancer patients. This study was done to identify the Candida species, which cause OPC, and to evaluate their antifungal susceptibility pattern and pathogenic characteristics in Iranian head and neck cancer patients treated by radiotherapy.

MATERIAL AND METHODS

The oral clinical samples were determined by culturing on CHROMagar, carbohydrate assimilation and ITS sequencing methods. Biofilm formation, phospholipase and proteinase activity and antifungal susceptibility were examined too.

RESULTS

Among 54 patients with confirmed OPC, 39 (72.22%) patients were male and 15 (27.77%) were female. The most frequently Candida species from a total of 60 isolates was C. albicans (53.3%), followed by C. tropicalis (21.66%), C. glabrata (15%), C. kefyr (5%) and C. dubliniensis (1.66%). All the isolates were high-producers of biofilm. All of Candida isolates were proteinase positive and 47 isolates (81.04%) represented phospholipase activity. The maximum and minimum rates of antifungal resistance belonged to ketoconazole (93.75% of C. albicans and 89.28% of Candida non-albicans) and fluconazole (62.50% and 42.85% of C. albicans and Candida non-albicans), respectively. The most effective antifungal against all candida isolates was fluconazole.

CONCLUSION

Our data can estimate abundance of OPC in male and female head and neck cancer patients and is helpful to use effective strategies for antifungal treatment, prophylaxis, and preventive therapies in these patients.

A study of changes in the oral fungal flora of patients on radiotherapy for head and neck malignancies and their correlation with funguria and fungemia

BACKGROUND

Patients of head and neck malignancies often develop oral mucositis and invite various pathogens to colonize over it.

OBJECTIVES

The objective of this study is to identify the fungi isolated from patients undergoing radiotherapy (RT) for head and neck cancer, to determine the antifungal susceptibility of these isolates and to determine the time and week of fungal colonization.

PATIENTS AND METHODS

Three specimens (throat, urine, and blood) were collected from each of the head and neck cancer patients, who were advised RT. These specimens, which were collected before the start of RT, during RT (2nd and 6th week), and post-RT (8th week) were inoculated into fungal culture media. Candida species were identified by standard methods and antifungal susceptibility of the candidal isolates was done.

RESULTS

Candida infection was found in 24/42 patients (57.14%) out of which Candida albicans was isolated in 14.28%, Candida tropicalis (28.57%) and Candida parapsilosis (14.28%). Maximum isolation of yeast was in the 6th week of RT. Fungemia was found in 3/42 patients. All the yeast isolates were sensitive to fluconazole except two.

CONCLUSION

Prophylactic antifungal therapy in patients undergoing RT for head and neck malignancy is particularly important to prevent intraoral colonization and infection by Candida. Screening of such patients on RT for fungal infections can prevent fatal mold infections.

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.

An in vitro study of isolation of candidal strains in oral squamous cell carcinoma patients undergoing radiation therapy and quantitative analysis of the various strains using CHROMagar

Background:

Patients undergoing radiation therapy for oral squamous cell carcinoma (OSCC) have an increased risk of developing oral candidiasis. Radiation-induced hyposalivation is thought to be a major predisposing factor for it. Radiation therapy for 2–3 weeks leads to increase in the number of candidal species in the oral cavity, eventually leading to oral candidiasis.

Objective:

To evaluate and correlate the prevalence of candidal species in the oral cavity of OSCC patients and to compare with radiation dosage at 3^rd and 6^th week following radiotherapy.

Materials and Methods:

This study includes fifty patients undergoing radiation therapy for OSCC. Patients were examined at 3^rd and 6^th week following radiation therapy, and smear samples were obtained from lesional sites and the radiation dose was recorded. Smear samples were cultured on CHROMagar, and identification of various candidal species was done on the basis of colony color and their morphology.

Results:

The present study isolated four types of candidal species, namely, Candida albicans, Candida glabrata, Candida tropicalis and Candida krusei. All the organisms, except C. krusei, showed a significant increase from 3^rd to 6^th week of radiotherapy whereas C. glabrata and C. tropicalis showed a sudden exponential increase. Total radiation dosage did not show any correlation to candidal colonization at 3^rd and 6^th week following radiotherapy.

Conclusion:

OSCC patients undergoing radiotherapy show an increase in candidal colonization which is independent of radiation dosage and may be related to other factors. However, such findings should be further evaluated using a larger sample size.

Spectrum of fungal infection in head and neck cancer patients on chemoradiotherapy

BACKGROUND

Radiotherapy for head and neck cancers (HNC) causes alteration of oral mucosal barrier predisposing it to colonization and infection. Such infections often result in pain and burning sensation thus contributing to major morbidity.

OBJECTIVE

MATERIALS AND METHODS: Study was done on 50 patients of HNC treated with concurrent chemoradiotherapy. Three samples (throat, urine, blood) were collected for fungal culture and sensitivity. These samples were collected before the start of radiotherapy, during radiotherapy (2nd and 6th week) and post radiotherapy (10th week).

RESULTS

Only 49 patients were available for analysis. Fungal infection was found in 27/49 patients (55.10%) out of which Non-albicans Candida was isolated in 18/49 (36.73%) and Candida albicans in 9/49 (18.36%) cases. About 66.66% (18/27) isolates were sensitive to fluconazole. Maximum isolation of yeast was during 6th week of radiotherapy. All grade 4 and 71.42% of grade 3 oral mucositis were found in patients who were positive for fungal infection.

CONCLUSION

The spectrum of fungal species in throat swab was: Non-albicans Candida and Candida albicans observed in 36.73% and 18.36% of patients respectively. Higher rate of fungal colonization and infection was found in patients with grade 3/4 oral mucositis. Prophylactic fluconazole in HNC patients on concurrent chemoradiotherapy has the potential to reduce emerging invasive fungal infection and its associated morbidity.

Influence of cancer treatment on the Candida albicans isolated from the oral cavities of cancer patients

PURPOSE

Cancer treatment causes mucositis and the manifestation of oral candidiasis. This study investigated the virulence properties and antifungal susceptibilities of Candida albicans isolated from cancer patients undergoing therapy.

METHODS

C. albicans were isolated from 49 patients on cancer treatment and 21 healthy individuals and their virulence attributes measured. A correlation was determined between the length of treatment and the fungal counts and their virulence factors.

RESULTS

Although Candida carriage was similar in all the study groups, high quantities of C. albicans and variety of Candida were found in cancer patients. Germ tubes were produced by all the strains. Significantly high number of yeast isolated from radiotherapy and chemotherapy produced large quantities of phospholipase compared to healthy individuals (p < 0.01). The length of chemotherapy was associated with an increase in the phospholipase production (p = 0.03) by the C. albicans. Proteinase production was seen in a significant number of isolates from the radiotherapy group (p < 0.01). Type of cancer treatment had no effect. Resistance to antifungal agents was low.

CONCLUSIONS

High quantities of phospholipase were produced by C. albicans in cancer patients on therapy which also increased with the length of chemotherapy suggesting enhanced risk of oral and systemic infection. Therefore, during treatment, prophylactic topical antifungal therapy may be considered.

Acute periodontal lesions

This review provides updates on acute conditions affecting the periodontal tissues, including abscesses in the periodontium, necrotizing periodontal diseases and other acute conditions that cause gingival lesions with acute presentation, such as infectious processes not associated with oral bacterial biofilms, mucocutaneous disorders and traumatic and allergic lesions. A periodontal abscess is clinically important because it is a relatively frequent dental emergency, it can compromise the periodontal prognosis of the affected tooth and bacteria within the abscess can spread and cause infections in other body sites. Different types of abscesses have been identified, mainly classified by their etiology, and there are clear differences between those affecting a pre-existing periodontal pocket and those affecting healthy sites. Therapy for this acute condition consists of drainage and tissue debridement, while an evaluation of the need for systemic antimicrobial therapy will be made for each case, based on local and systemic factors. The definitive treatment of the pre-existing condition should be accomplished after the acute phase is controlled. Necrotizing periodontal diseases present three typical clinical features: papilla necrosis, gingival bleeding and pain. Although the prevalence of these diseases is not high, their importance is clear because they represent the most severe conditions associated with the dental biofilm, with very rapid tissue destruction. In addition to bacteria, the etiology of necrotizing periodontal disease includes numerous factors that alter the host response and predispose to these diseases, namely HIV infection, malnutrition, stress or tobacco smoking. The treatment consists of superficial debridement, careful mechanical oral hygiene, rinsing with chlorhexidine and daily re-evaluation. Systemic antimicrobials may be used adjunctively in severe cases or in nonresponding conditions, being the first option metronidazole. Once the acute disease is under control, definitive treatment should be provided, including appropriate therapy for the pre-existing gingivitis or periodontitis. Among other acute conditions affecting the periodontal tissues, but not caused by the microorganisms present in oral biofilms, infectious diseases, mucocutaneous diseases and traumatic or allergic lesions can be listed. In most cases, the gingival involvement is not severe; however, these conditions are common and may prompt an emergency dental visit. These conditions may have the appearance of an erythematous lesion, which is sometimes erosive. Erosive lesions may be the direct result of trauma or a consequence of the breaking of vesicles and bullae. A proper differential diagnosis is important for adequate management of the case.

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.