Effect of silver sulfadiazine on mature mixed bacterial biofilms on voice prostheses.

BACKGROUND: Biofilm formation on voice prostheses disrupts the function and limits the lifespan of voice prostheses. There is still no effective clinical strategy for inhibiting or removing these biofilms. Silver sulfadiazine (SSD), as an exogenous antibacterial agent, has been widely used in the prevention and treatment of infection, however, its effect on voice prosthesis biofilms is unknown. The purpose of this study was to explore the effect of SSD on the mature mixed bacterial biofilms present on voice prostheses. METHODS: Quantitative and qualitative methods, including the plate counting method, real-time fluorescence quantitative PCR, crystal violet staining, the 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide) (XTT) reduction assay, scanning electron microscopy, and laser confocal microscopy, were used to determine the effect of SSD on the number of bacterial colonies, biofilm formation ability, metabolic activity, and ultrastructure of biofilms in a mature mixed bacterial (Staphylococcus aureus, Streptococcus faecalis and Candida albicans) voice prosthesis biofilm model. The results were verified in vitro on mature mixed bacterial voice prosthesis biofilms from patients, and the possible mechanism of action was explored. RESULTS: Silver sulfadiazine decreased the number of bacterial colonies on mature mixed bacterial voice prosthesis biofilm, significantly inhibited the biofilm formation ability and metabolic activity of mature voice prosthesis biofilms, inhibited the formation of the complex spatial structure of voice prosthesis biofilms, and inhibited the synthesis of polysaccharides and proteins in the biofilm extracellular matrix. The degree of inhibition and removal effect increased with SSD concentration. CONCLUSIONS: Silver sulfadiazine can effectively inhibit and remove mature mixed bacterial voice prosthesis biofilms and decrease biofilm formation ability and metabolic activity; SSD may exert these effects by inhibiting the synthesis of polysaccharides and proteins among the extracellular polymeric substances of voice prosthesis biofilms.

In vitro Inhibition of Biofilm Formation on Silicon Rubber Voice Prosthesis: Α Systematic Review and Meta-Analysis.

INTRODUCTION: Biofilm formation on voice prostheses is the primary reason for their premature implant dysfunction. Multiple strategies have been proposed over the last decades to achieve inhibition of biofilm formation on these devices. The purpose of this study was to assess the results of the available in vitro biofilm inhibition modalities on silicone rubber voice prostheses. METHODS: We conducted a systematic search in PubMed, Embase, and the Cochrane Central Register of Controlled Trials databases up to February 29, 2020. A total of 33 in vitro laboratory studies investigating the efficacy of different coating methods against Candida, Staphylococcus, Streptococcus, Lactobacilli, and Rothia biofilm growth on silicone rubber medical devices were included. Subgroup analysis linked to the type of prevention modality was carried out, and quality assessment was performed with the use of the modified CONSORT tool. RESULTS: Data from 33 studies were included in qualitative analysis, of which 12 qualified for quantitative analysis. For yeast biofilm formation assessment, there was a statistically significant difference in favor of the intervention group (standardized mean difference [SMD] = -1.20; 95% confidence interval [CI] [-1.73, -0.66]; p < 0.0001). Subgroup analysis showed that combined methods (active and passive surface modification) are the most effective for biofilm inhibition in yeast (SMD = -2.53; 95% CI [-4.02, -1.03]; p = 0.00001). No statistically significant differences between intervention and control groups were shown for bacterial biofilm inhibition (SMD = -0.09; 95% CI [-0.68, 0.46]; p = 0.65), and the results from the subgroup analysis found no notable differences between the surface modification methods. After analyzing data on polymicrobial biofilms, a statistically significant difference in favor of prevention methods in comparison with the control group was detected (SMD = -2.59; 95% CI [-7.48, 2.31]; p = 0.30). CONCLUSIONS: The meta-analysis on biofilm inhibition demonstrated significant differences in favor of yeast biofilm inhibition compared to bacteria. A stronger inhibition with the application of passive or combined active and passive surface modification techniques was reported.

Growth Media for Mixed Multispecies Oropharyngeal Biofilm Compositions on Silicone.

AIMS: Microbial colonization of silicone voice prostheses by bacteria and Candida species limits the device lifetime of modern voice prostheses in laryngectomized patients. Thus, research focuses on biofilm inhibitive properties of novel materials, coatings, and surface enhancements. Goal of this in vitro study was the evaluation of seven commonly used growth media to simulate growth of mixed oropharyngeal species as mesoscale biofilms on prosthetic silicone for future research purposes. METHODS AND RESULTS: Yeast Peptone Dextrose medium (YPD), Yeast Nitrogen Base medium (YNB), M199 medium, Spider medium, RPMI 1640 medium, Tryptic Soy Broth (TSB), and Fetal Bovine Serum (FBS) were used to culture combined mixed Candida strains and mixed bacterial-fungal compositions on silicone over the period of 22 days. The biofilm surface spread and the microscopic growth showed variations from in vivo biofilms depending on the microbial composition and growth medium. CONCLUSION: YPD and FBS prove to support continuous in vitro growth of mixed bacterial-fungal oropharyngeal biofilms deposits over weeks as needed for longterm in vitro testing with oropharyngeal biofilm compositions. SIGNIFICANCE AND IMPACT OF STUDY: The study provides data on culture conditions for mixed multispecies biofilm compositions that can be used for future prosthesis designs.

Biofilm in voice prosthesis: A prospective cohort study and laboratory tests using sonication and SEM analysis.

OBJECTIVE: The objective of the study was to compare the biofilm growing pattern and its morphological extent on silicone and a teflon-like material using a sonication process and a Scanning Electron Microscope (SEM). DESIGN: A prospective cohort study and a laboratory study. SETTING: Otolaryngology -Head and Neck surgery Department and the Microbiology Institute. PARTICIPANTS: The participants included fifteen laryngectomised patients with phonatory prostheses, which were removed because of device failure, and two different kinds of phonatory prostheses from the laboratory (Provox 2 and ActiValve) that were artificially colonised by Candida albicans. MAIN OUTCOME MEASURES: Tracheo-oesophageal puncture (TEP) is currently considered the gold standard for post-laryngectomy voice rehabilitation. "Leakage" represents the most common cause of substitution and is generated by biofilm colonisation of the prosthesis by mixed mycotic and bacterial agents. New biomaterials have been developed that are deemed to be more resistant to the colonisation of micro-organisms and material deformation. RESULTS: The devices showed colonisation by mixed bacterial flora (Staphylococci 13%, Streptococci 9%, and Haemophilus influenzae 5%) and by yeasts (Candida albicans 12%). Moreover, we observed a different distribution of biofilm layers in Provox ActiValve (22.56%) compared to Provox 2 (56.82%) after experimental colonisation by the previously isolated Candida strain. CONCLUSION: Resident microbiological species from the upper airways unavoidably colonise the polymer surfaces, and no strategies have been effective except for the manipulation of the chemical-physical properties of the device's polymer. Our study confirms that Provox ActiValve, which is made with a fluoroplastic material (teflon-like), is less subject to in vitro colonisation by Candida, and thus showed a higher clinical resistance to biofilm and a longer lifespan. The sonication seems to significantly improve the knowledge of bacterial and mycotic flora in biofilm colonisation. The design of a device for the daily cleaning capable to reach and brush the oesophageal flange of the prosthesis preserving the valve mechanism could represent a practical and simple help in this still unsolved problem.

In vitro biofilm growth on modern voice prostheses.

BACKGROUND: Biofilm formation on voice prostheses in laryngectomized patients usually limits the lifetime of the device. The purpose of this study was to compare the biofilm resistance of different valve flaps of modern voice prostheses in an in vitro simulation of an oropharyngeal biofilm. METHODS: Growth of biofilm deposits on valve flaps (n = 12) removed from Provox 2, Provox Vega, Provox ActiValve, Blom Singer Advantage, and Phonax voice prostheses was evaluated and compared to medical-grade silicone (n = 12) in an in vitro biofilm model (22 days) after incubation with a multispecies bacterial-fungal biofilm composition. RESULTS: The Provox ActiValve and the Blom Singer Advantage prostheses showed significantly less surface biofilm formation than the other prostheses and then silicone. CONCLUSION: The use of silver oxide and Teflon as valve flap materials proves to reduce long-term biofilm formation in vitro. The applied model allows rapid screening for novel biofilm-inhibitive materials and durable coatings designated for more biofilm resistant medical devices.

Inhibition activity of Lactobacilli supernatant against fungal-bacterial multispecies biofilms on silicone.

Fungal-bacterial multispecies biofilms play a major role in failure of medical silicone devices, such as voice prostheses in laryngectomiy. In this study, we determined the effect of Lactobacilli supernatant (cell free) on mixed biofilm formation of fungi and bacteria on silicone in vitro. Lactobacilli supernatant inhibited the adhesion (90 min) of mixed fungi and bacteria species with an efficiency of >90%. Mixed biofilm formation and the metabolic activity of the biofilms were inhibited by 72.23% and 58.36% by Lactobacilli supernatant. The examination using confocal laser scanning microscopy and scanning electron microscopy confirmed that Lactobacilli supernatant inhibited the growth of mixed biofilm and damaged the cells. Moreover, Lactobacilli supernatant also inhibited Candida yeast-to-hyphal transition. Therefore, Lactobacilli supernatant may serve as a possible antibiofilm agent to limit biofilm formation on voice prostheses.

Biofilm on the tracheoesophageal voice prosthesis: considerations for oral decontamination.

The tracheoesophageal puncture (TEP) restores verbal communication after total laryngectomy using a one-way valved voice prosthesis (VP). Microbial colonization can shorten VP device life. Our aims were to investigate patterns of prosthetic and oral colonization, and record changes in VP device life after targeted decontamination. We conducted a retrospective review of TEP clinic patients who underwent microbial analysis of the VP between 01/2003 and 07/2013. Two subgroups were analyzed: (1) patients with microbial analysis of the VP and the mouth were analyzed to identify patterns of common contamination, and (2) patients who were prescribed targeted oral decontamination on the basis of the microbial analysis of the VP were analyzed to evaluate effects on device life. Among 42 patients, 3 patients had only fungal, 5 only bacterial, and 33 had polyspecies fungal and bacterial colonization. In the TEP-oral microflora subgroup (n = 15), 7 had common microorganisms in the mouth and on the VP. Among the decontamination subgroup (n = 23), 6 patients received broad spectrum rinse, 16 antifungal agents and 13 antibiotics, or a combination thereof. After targeted decontamination, the median device life of prostheses improved from 7.89 to 10.82 weeks (p = 0.260). The majority of patients with a suboptimal VP device life in this pilot had polyspecies bacterial and fungal colonization. VPs rarely had fungal contamination alone (3 %), and non-albicans fungal species were more common than expected. For these reasons, we are exploring the use of targeted decontamination regimens that were associated with 1.4-fold improvement in VP duration.

Influence of culture conditions for clinically isolated non-albicans Candida biofilm formation.

Non-albicans Candida species have been isolated in increasing numbers in patients. Moreover, they are adept at forming biofilms. This study analyzed biofilm formation of clinically isolated non-albicans Candida, including Candida tropicalis, Candida krusei and Candida parapsilosis under the influence of different growth media (RPMI 1640, YPD and BHI) and several culture variables (inoculum concentration, incubation period and feeding conditions). The results showed that culture conditions strongly influenced non-albicans Candida species biofilm formation. YPD and BHI resulted in larger amount of biofilm formation with higher metabolic activity of biofilms. Furthermore, the growth media seems to have varying effects on adhesion and biofilm development. Growth conditions may also influence biofilm formation, which was enhanced when starting the culture with a larger inoculum, longer incubation period and using a fed-batch system. Therefore, the potential influences of external environmental factors should be considered when studying the non-albicans Candida biofilms in vitro.

Long-term antibiofilm activity of carboxymethyl chitosan on mixed biofilm on silicone.

OBJECTIVES/HYPOTHESIS: Silicone voice prostheses are most frequently used in voice rehabilitation of laryngectomized patients. However, the functional device lifetimes are limited due to formation of mixed biofilms. Existing in vitro models simulating biofilm formation are restricted to only short-term periods. STUDY DESIGN: The goal of this study was to determine the effect of carboxymethyl chitosan on mixed biofilm formation of fungi and bacteria on silicone over a long-term period. METHODS: Mixed species biofilms of Candida albicans, Candida tropicalis, Lactobacillus gasseri, Streptococcus salivarius, Rothia dentocariosa, and Staphylococcus epidermidis were cultivated on the surfaces of medical-grade silicone with and without addition of carboxymethyl chitosan. Biofilm kinetics was monitored using specially designed image analysis software to calculate the percentual surface covering of each platelet. Biofilm architecture was investigated by scanning electron microscopy. RESULTS: A cover of living mixed biofilm could be generated over 22 days on silicone and the maximum of 22% biofilm surface covering at day 22. However, less than 4% surface coverage was observed on the carboxymethyl chitosan-treated plates in the testing period. Scanning electron microscopy confirms that, on surfaces treated by carboxymethyl chitosan, the biofilm was less dense. In addition, there were fewer layers of cells and profuse cellular debris, together with degrading and morphologically altered yeast cells. CONCLUSION: Carboxymethyl chitosan may serve as a possible antibiofilm agent to limit biofilm formation on voice prostheses. LEVEL OF EVIDENCE: NA Laryngoscope, 126:E404-E408, 2016.

Vibratory stimulus reduces in vitro biofilm formation on tracheoesophageal voice prostheses.

OBJECTIVES/HYPOTHESIS: Demonstrate that biofilm formation will be reduced on tracheoesophageal prostheses when vibratory stimulus is applied, compared to controls receiving no vibratory stimulus, in a dynamic in vitro model of biofilm accumulation simulating the interface across the tracheoesophageal puncture site. STUDY DESIGN: Prospective, randomized, controlled, crossover in university laboratory. METHODS: Ex vivo tracheoesophageal prostheses were obtained from university-affiliated speech language pathologists at Indiana University School of Medicine, Indianapolis. Prostheses demonstrating physical integrity and an absence of gross biofilm accumulation were utilized. Sixteen prostheses were cleansed and sterilized prior to random placement by length in two modified Robbins devices arranged in parallel. Each device was seeded with a polymicrobial oral flora on day 1 and received basal artificial salivary flow continuously with three growth medium meals daily. One device was randomly selected for vibratory stimulus, and 2 minutes of vibration was applied to each prosthesis before and after meals for 5 days. The prostheses were explanted and sonicated, and the biofilm cultured for enumeration. This process was repeated after study arm crossover. RESULTS: Tracheoesophageal prostheses in the dynamic model receiving vibratory stimulus demonstrated reduced gross biofilm accumulation and a significant biofilm colony forming unit per milliliter reduction of 5.56-fold compared to nonvibratory controls (P < 0.001). Significant reductions were observed within length subgroups. CONCLUSION: Application of vibratory stimulus around meal times significantly reduces biofilm accumulation on tracheoesophageal prostheses in a dynamic in vitro model. Further research using this vibratory stimulus method in vivo will be required to determine if reduced biofilm accumulation correlates with longer device lifespan. LEVEL OF EVIDENCE: NA Laryngoscope, 126:2752-2757, 2016.

Biofilm formation on the Provox ActiValve: Composition and ingrowth analyzed by Illumina paired-end RNA sequencing, fluorescence in situ hybridization, and confocal laser scanning microscopy.

BACKGROUND: The most frequent cause of voice prosthesis failure is microbial biofilm formation on the silicone valve, leading to destruction of the material and transprosthetic leakage. The Provox ActiValve valve is made of fluoroplastic, which should be insusceptible to destruction. The purpose of this study was to determine if fluoroplastic is insusceptible to destruction by Candida species. METHODS: Thirty-three dysfunctional Provox ActiValves (collected 2011-2013). Biofilm analysis was performed with Illumina paired-end sequencing (IPES), assessment of biofilm-material interaction with fluorescence in situ hybridization (FISH), and confocal laser scanning microscopy (CLSM). RESULTS: IPES (n = 10) showed that Candida albicans and Candida tropicalis are dominant populations on fluoroplastic and silicone. Microbial diversity is significantly lower on fluoroplastic. Lactobacillus gasseri is the prevalent bacterial strain on most voice prostheses. FISH and CLSM (n = 23): in none of the cases was ingrowth of Candida species present in the fluoroplastic. CONCLUSION: Fluoroplastic material of Provox ActiValve seems insusceptible to destruction by Candida species, which could help improve durability of voice prostheses. © 2015 Wiley Periodicals, Inc. Head Neck 38: E432-E440, 2016.

The role of biofilm in chronic laryngitis and in head and neck cancer.

PURPOSE OF REVIEW: The importance of bacterial biofilm in the human body, both when associated in chronic infections and as the default mode of microbial growth in the normal flora, has been understood during the last two decades. The word biofilm has recently entered into clinical vocabulary especially in dentistry, and oral hygienists have begun to talk of oral or dental biofilm instead of oral plaque. Biofilm presence has been demonstrated widely in otorhinolaryngology, related to chronic infections of middle ear, paranasal sinuses and lymphoid tissue of adenoids and tonsils and to implanted materials; however, less literature exists considering the implication of biofilm to laryngeal infections or head and neck cancer. The research until now has been mainly descriptive and the mechanisms that lead to biofilm formation are unclear and thus there are limited options for specific treatment of biofilm infection. The focus of this article is to review the recent literature considering the bacterial biofilm in larynx and in head and neck surgery. RECENT FINDINGS: Bacterial biofilm has now also been implicated in chronic laryngitis. Among head and neck cancer patients, biofilm is the main reason for the short life cycle of indwelling devices such as voice prostheses and tracheal tubes. Recently, bacterial biofilm has been related to dysplasia and malignancies both as an aetiological factor and as a source of complications. SUMMARY: It has been shown that microbial biofilm is implicated in the mechanisms leading to chronic recalcitrant infections, implant contamination and even to dysplasia. Biofilm has an important role in finding new preventive measures and treatment of these diseases.

Candida biofilm formation on voice prostheses.

Laryngopharyngeal malignancy is treated with radiotherapy and/or surgery. When total laryngectomy is required, major laryngeal functions (phonation, airway control, swallowing and coughing) are affected. The insertion of a silicone rubber voice prosthesis in a surgically created tracheoesophageal puncture is the most effective method for voice rehabilitation. Silicone, as is the case with other synthetic materials such as polymethylmethacrylate, polyurethane, polyvinyl chloride, polypropylene and polystyrene, has the propensity to become rapidly colonized by micro-organisms (mainly Candida albicans) forming a biofilm, which leads to the failure of the devices. Silicone is used within voice prosthetic devices because of its flexible properties, which are essential for valve function. Valve failure, as well as compromising speech, may result in aspiration pneumonia, and repeated valve replacement may lead to either tract stenosis or insufficiency. Prevention and control of biofilm formation are therefore crucial for the lifespan of the prosthesis and promotion of tracheoesophageal tissue and lung health. To date, the mechanisms of biofilm formation on voice prostheses are not fully understood. Further studies are therefore required to identify factors influencing Candida biofilm formation. This review describes the factors known to influence biofilm formation on voice prostheses and current strategies employed to prolong their life by interfering with microbial colonization.

Voice prostheses, microbial colonization and biofilm formation.

Total laryngectomy is performed in advanced laryngeal and hypopharyngeal cancer stages and results in reduced quality of life due to the loss of voice and smell, permanent tracheostoma and occasionally dysphagia. Therefore, successful voice rehabilitation is highly beneficial for the patients' quality of life after surgery. Over the past decades, voice prostheses have evolved to the gold standard in rehabilitation and allow faster and superior voicing results after laryngectomy compared to esophageal speech. Polyspecies biofilm formation has become the limiting factor for device lifetimes and causes prosthesis dysfunction, leakage and in consequence pneumonia, if not replaced immediately. Although major improvements in prosthesis design have been made and scientific insight in the complexity of biofilm evolution and material interaction progresses, the microbial colonization continues to restrict device lifetimes, causing patient discomfort and elevated health costs. However, present scientific findings and advances in technology yield promising future approaches to improve the situation for laryngectomized patients.

Oral cavity anaerobic pathogens in biofilm formation on voice prostheses.

BACKGROUND: A polymerase chain reaction (PCR)-based method has been used to identify oral anaerobic pathogens in biofilms on voice prostheses. The purpose of the present study was to determine the location of those pathogens inside the biofilms. METHODS: Biofilms of 15 voice prostheses were sampled and used to identify the oral pathogens. Fluorescence in situ hybridization was applied on smears made on glass slides and on sections of intact biofilms visualized by confocal laser scanning microscopy (CLSM). RESULTS: Fusobacterium nucleatum (F. nucleatum) was the most frequently detected pathogen and the only tested species detected in microcolonies. The other microbes (Parvimonas micra [P. micra], Porphyromonas gingivalis [P. gingivalis], Tannerella forsythia [T. forsythia], and Treponema denticola [T. denticola]) were not detected or only detected as single cells. CLSM analysis showed that F. nucleatum resided on the biofilm surface. CONCLUSION: Although detectable, oral anaerobic pathogens seem to be no more than passers-by that adhere without further observed proliferation and apparently play no striking role in biofilm formation on voice prostheses.

Microbial colonization of Provox voice prosthesis in the Indian scenario.

INTRODUCTION: Tracheoesophageal speech using the voice prosthesis is considered to be the "gold standard" with success rates as high as 90%. Despite significant developments, majority eventually develop dysfunction due to microbial deterioration. We did a pilot study of 58 laryngectomy patients who developed prosthesis dysfunction. MATERIALS AND METHODS: A total of 58 laryngectomy patients who had their dysfunctional prosthesis removed were included in this study. Dysfunctional prostheses were removed and examined. Esophageal and tracheal flanges were examined separately. After obtaining pure fungal and bacterial cultures, the yeast strains were identified. Bacteria were identified with the light microscope and gram staining. We analyzed prosthesis lifespan and probable factors affecting it. RESULTS: Central leak was found in 43% cases while in 57% peri-prosthetic leakage was the most common reason for prosthesis replacement. Microbial analysis revealed a combination of yeast and bacteria in approximately 55% culture samples. Out of these, almost 90% had the presence of single yeast species with bacteria. Pure fungal culture was identified in rest of the 45% cultures while none detected pure bacterial forms. Candida tropicalis was the solitary yeast in 81% while Candida albicans was seen in 10% as the solitary yeast. Bacterial isolates revealed Klebsiella pneumonia in 19%, Escherichia coli in 8% while Staphylococcus aureus was grown in 1% cultures. The consumption of curd (P = 0.036, 95% confidence intervals [CI]: 2.292-64.285) to have a significant correlation of the mean prosthesis lifespan. Consumption of curd (P = 0.001, 95% CI: 0.564-2.008) and history of prior radiotherapy (P = 0.015, 95% CI: 0.104-0.909) had a significant bearing on the Provox prosthesis lifespan. CONCLUSIONS: Candida is the most common organism grown on voice prosthesis in Indian scenario. Consumption of curd and history of prior radiotherapy significantly affect Provox prosthesis lifespan.

Voice prosthetic biofilm formation and Candida morphogenic conversions in absence and presence of different bacterial strains and species on silicone-rubber.

Morphogenic conversion of Candida from a yeast to hyphal morphology plays a pivotal role in the pathogenicity of Candida species. Both Candida albicans and Candida tropicalis, in combination with a variety of different bacterial strains and species, appear in biofilms on silicone-rubber voice prostheses used in laryngectomized patients. Here we study biofilm formation on silicone-rubber by C. albicans or C. tropicalis in combination with different commensal bacterial strains and lactobacillus strains. In addition, hyphal formation in C. albicans and C. tropicalis, as stimulated by Rothia dentocariosa and lactobacilli was evaluated, as clinical studies outlined that these bacterial strains have opposite results on the clinical life-time of silicone-rubber voice prostheses. Biofilms were grown during eight days in a silicone-rubber tube, while passing the biofilms through episodes of nutritional feast and famine. Biofilms consisting of combinations of C. albicans and a bacterial strain comprised significantly less viable organisms than combinations comprising C. tropicalis. High percentages of Candida were found in biofilms grown in combination with lactobacilli. Interestingly, L. casei, with demonstrated favorable effects on the clinical life-time of voice prostheses, reduced the percentage hyphal formation in Candida biofilms as compared with Candida biofilms grown in absence of bacteria or grown in combination with R. dentocariosa, a bacterial strain whose presence is associated with short clinical life-times of voice prostheses.

[A review of the complications and candida colonization associated with voice rehabilitation using a voice prosthesis].

Between December 2004 and December 2011, we have used the indwelling voice prosthesis for voice rehabilitation in 28 patients after total laryngectomy in our department. To clarify both the complications and safety of voice reconstruction using a voice prosthesis, and the occurrence of candida colonization, we conducted a retrospective study with a review of the Japanese literature. Twenty-six patients who were observed over a period of more than six months at our hospital were enrolled in this study. We examined the interval of prosthesis replacement, types and frequency of complications, candida colonization, and clinical outcomes. The median follow-up time postoperatively was 28.8 months (range 8.1-95.7). The average interval of prosthesis replacement was 147 days (4.9 months). Complications occurred in 14 patients (54%), and 6 patients (23%) of whom were hospitalized. The main complications were periprosthetic leakage, increased granulation around the tracheoesophageal shunt and stenosis of the trachea stoma. There were no significant differences in the frequency of complications in the background factor of the patients as far as age (p = 0.495), radiation therapy (p = 0.686) or reconstruction time (p = 0.257) were concerned. Candida species was detected in 81% of the specimens which we submitted to a culture test and confirmed the pseudohyphae which comfirmed the pathogenicity from the histopathological examination. Moreover, radiation therapy was significantly associated with the detection of candida (p = 0.004). Permanent closure of the tracheoesophageal shunt for periprosthetic leakage was required in one patient, but we were able to deal with the other complications. No patient experienced any life-threatening complications and all are safely using the prostheses. It has been reported that complications will occur over the long-term, thus careful follow-up is necessary.

Adherence of Candida albicans to silicone is promoted by the human salivary protein SPLUNC2/PSP/BPIFA2.

Interactions between Candida albicans, saliva and saliva-coated oral surfaces are initial events in the colonization of the oral cavity by this commensal yeast, which can cause oral diseases such as candidiasis and denture stomatitis. Candida albicans also colonizes silicone voice prostheses, and the microbial biofilm formed can impair valve function, necessitating frequent prosthesis replacement. We have previously shown that saliva promoted binding of C. albicans cells to silicone in vitro, and that the selective binding of specific salivary proteins to voice prosthesis silicone mediated attachment of C. albicans cells. The C. albicans cells adhered to a polypeptide (or polypeptides) of ~36 kDa eluted from saliva-treated silicone. We show here that a protein of similar size was identified in replicate blots of the eluate from saliva-treated silicone when the blots were probed with antibodies to human SPLUNC2, a salivary protein with reported microbial agglutination properties. In addition, SPLUNC2 was depleted from saliva that had been incubated with silicone coupons. To determine whether SPLUNC2 is a yeast-binding protein, SPLUNC2 cDNA was expressed in Escherichia coli. Purified recombinant His-tagged protein (SPLUNC2r) bound to silicone as demonstrated by immunoblot analysis of an eluate from SPLUNC2r-treated silicone coupons and (35) S-radiolabelled C. albicans cells adhered in a dose-dependent manner to SPLUNC2r-coated silicone. We conclude that SPLUNC2 binds to silicone and acts as a receptor for C. albicans adherence to, and subsequent colonization of, voice prosthesis silicone.

[The use of the lactate-fortified milk whey for the prolongation of the functional life of the voice prostheses].

The objective of the present study was to develop the method for the prolongation of the functional life of the voice prostheses in the patients who underwent laryngectomy with special reference to the decrease of the risk of mycotic infection in the laryngo-oesophageal region. The original method is proposed with the application of the lactate-fortified milk whey that makes it possible to maintain the high concentration of living lactic acid bacteria in the laryngo-oesophageal segment where the voice prosthesis is located. The method was tested on 73 patients. It permitted to significantly prolong the functional life of the voice prostheses (from 12 to 20 months) and prevent mycotic infection. It is concluded that the proposed method promotes the improvement of the patients' quality of life following laryngectomy for the treatment of cancer.