Groningen Button Research Articles

Transcriptional Profiling of C. albicans in a Two Species Biofilm with Rothia dentocariosa.

Biofilms on silicone rubber voice prostheses are the major cause for frequent failure and replacement of these devices. The presence of both bacterial and yeast strains has been suggested to be crucial for the development of voice prosthetic biofilms. Polymicrobial biofilms that include Candida albicans and Rothia dentocariosa are the leading cause of voice prosthesis failure. An in vitro biofilm comprising these two organisms was developed on silicone rubber, a material used for Groningen button voice prosthesis. We found that this biofilm environment was not conducive for C. albicans growth or differentiation. Global transcriptional analyses of C. albicans biofilm cells grown with R. dentocariosa revealed that genes with functions related to cell cycle progression and hyphal development were repressed >2-fold. The mixed species biofilms were more compact and less robust compared to C. albicans mono-species biofilms, even when developed under conditions of continuous nutrient flow. Under these conditions R. dentocariosa also significantly inhibited C. albicans biofilm dispersal. Preferential adherence of R. dentocariosa to candidal hyphae was mediated by the adhesin Als3.

Prevention of biofilm formation by dairy products and N-Acetylcysteine on voice prostheses in an artificial throat

ObjectiveTo evaluate the preventive effect of buttermilk, Yakult Light fermented milk drink and N-acetylcysteine on biofilm formation on voice prostheses in vitro.Material and MethodsGroningen button and Provox®2 voice prostheses were inoculated with a mixture of bacteria and yeasts isolated from previously explanted Groningen button voice prostheses. After 5 h, separate throats were flushed with buttermilk, Yakult Light fermented milk drink, N-acetylcysteine or phosphate-buffered saline, which served as a control. After 7 days, the microflora on each voice prosthesis was determined.ResultsOn Groningen button voice prostheses, buttermilk, Yakult Light fermented milk drink and N-acetylcysteine all reduced the amount of both bacteria and yeasts. On Provox®2 voice prostheses, buttermilk, Yakult Light fermented milk drink and N-acetylcysteine reduced the amount of bacteria but, conversely, increased the amount of yeasts.ConclusionThese in vitro experiments demonstrate that biofilm formation on voice prostheses is reduced in an artificial throat by the use of buttermilk, Yakult Light fermented milk drink and N-acetylcysteine. However, the structural differences between the type of voice prostheses may influence the ultimate effects.

Influence of different combinations of bacteria and yeasts in voice prosthesis biofilms on air flow resistance.

Laryngectomized patients use silicone rubber voice prostheses to rehabilitate their voice. However, biofilm formation limits the lifetime of voice prostheses. The presence of particular combinations of bacterial and yeast strains in voice prosthesis biofilms has been suggested to be crucial for causing valve failure. In order to identify combinations of bacterial and yeast strains causative to failure of voice prostheses, the effects of various combinations of bacterial and yeast strains on air flow resistances of Groningen button voice prostheses were determined. Biofilms were grown on Groningen button voice prostheses by inoculating so-called artificial throats with various combinations of clinically relevant bacterial and yeast strains. After 3 days, all throats were perfused three times daily with 250 ml phosphate buffered saline and at the end of each day the artificial throats were filled with growth medium for half an hour. After 7 days, the air flow resistances of the prostheses were measured. These air flow resistances were expressed relative to the air flow resistances of the same prostheses prior to biofilm formation. This study shows that biofilms causing strong increases in air flow resistance (26 to 28 cm water x s/l) comprised combinations of microorganisms, involving Candida tropicalis, Staphylococcus aureus and Rothia dentocariosa.

In vitro formation of oropharyngeal biofilms on silicone rubber treated with a palladium/tin salt mixture

Adhesion of yeasts and bacteria to silicone rubber is one of the first steps in the biodeterioration of indwelling, silicone rubber voice prostheses. In this paper, silicone rubber, so-called “Groningen button,” voice prostheses were treated with a colloidal palladium/tin solution to form a thin metal coat intended to discourage biofilm formation. First it was demonstrated that this treatment did not negatively affect the airflow resistance of the prostheses or induce any cytotoxicity. Subsequently, palladium/tin-treated voice prostheses were placed in a modified Robbins device together with untreated control prostheses to evaluate biofilm formation. Biofilms were formed by inoculating the device for 3 days with the total cultivable microflora obtained from an explanted, malfunctioning voice prosthesis supplemented with separately isolated yeasts (Candida albicans and Candida tropicalis). After 3 days the device was perfused three times daily with growth medium and phosphate-buffered saline. The device was allowed to drain between perfusions to better mimic the conditions in the oropharynx (moist but not always fully wetted). After 9 days the total number of bacterial and fungal colony-forming units on the prostheses were determined microbiologically, and scanning electron micrographs were taken of the valve sides. Biofilm formation was significantly less on the heavily treated palladium/tin prostheses than it was on the untreated prostheses although some ingrowing microcolonies also were observed on the treated prostheses. The spread of the biofilms was smaller on the treated prostheses than on the untreated ones. © 2000 John Wiley & Sons, Inc. J Biomed Mater Res, 51, 408–412, 2000.

In vitro formation of oropharyngeal biofilms on silicone rubber treated with a palladium/tin salt mixture

Adhesion of yeasts and bacteria to silicone rubber is one of the first steps in the biodeterioration of indwelling, silicone rubber voice prostheses. In this paper, silicone rubber, so-called "Groningen button," voice prostheses were treated with a colloidal palladium/tin solution to form a thin metal coat intended to discourage biofilm formation. First it was demonstrated that this treatment did not negatively affect the airflow resistance of the prostheses or induce any cytotoxicity. Subsequently, palladium/tin-treated voice prostheses were placed in a modified Robbins device together with untreated control prostheses to evaluate biofilm formation. Biofilms were formed by inoculating the device for 3 days with the total cultivable microflora obtained from an explanted, malfunctioning voice prosthesis supplemented with separately isolated yeasts (Candida albicans and Candida tropicalis). After 3 days the device was perfused three times daily with growth medium and phosphate-buffered saline. The device was allowed to drain between perfusions to better mimic the conditions in the oropharynx (moist but not always fully wetted). After 9 days the total number of bacterial and fungal colony-forming units on the prostheses were determined microbiologically, and scanning electron micrographs were taken of the valve sides. Biofilm formation was significantly less on the heavily treated palladium/tin prostheses than it was on the untreated prostheses although some ingrowing microcolonies also were observed on the treated prostheses. The spread of the biofilms was smaller on the treated prostheses than on the untreated ones.

The influence of dairy products on biofilm formation on the Groningen button and Provox II voice prostheses in an artificial throat

The influence of dairy products on biofilm formation on the Groningen button and Provox II voice prostheses in an artificial throat

In vitro and in vivo microbial adhesion and growth on argon plasma-treated silicone rubber voice prostheses.

Patients who undergo a total laryngectomy usually receive a silicone rubber voice prosthesis for voice rehabilitation. Unfortunately, biofilm formation on the esophageal side of voice prostheses limits their lifetime to 3-4 mon on average. The effects of repeated argon plasma treatment of medical grade, hydrophobic silicone rubber on in vitro adhesion and growth of bacteria and yeasts isolated from voice prostheses, as well as in vivo biofilm formation are presented here. In vitro experiments demonstrated that initial microbial adhesion over a 4 h time span to plasma-treated, hydrophilized, silicone rubber was generally less than on original, hydrophobic silicone rubber, both in the absence and presence of a salivary conditioning film on the biomaterial. Growth studies over a time period of 14 d at 37 degrees C in a modified Robbins device, showed that fewer Candida cells adhered on plasma-treated, hydrophilized silicone rubber as compared to on original, hydrophobic silicone rubber. For the in vivo evaluation of biofilm formation on plasma-treated silicone rubber voice prostheses, seven laryngectomized patients received a partly hydrophilized "Groningen Button" voice prosthesis for a planned evaluation period of 4 wk. After removal of the voice prostheses, the border between the hydrophilized and the original, hydrophobic side of the prostheses was clearly visible. However, biofilm formation was, unexpectedly, less on the original, hydrophobic sides, although the microbial compositions of the biofilms on both sides were not significantly different. Summarizing, this study demonstrates that in vitro microbial adhesion and growth on silicone rubber can be reduced by plasma treatment, but in vivo biofilm formation on silicone rubber voice prostheses is oppositely enhanced by hydrophilizing the silicone rubber surface. Nevertheless, from the results of this study the important conclusion can be drawn that in vivo biofilm formation on voice prostheses is controlled by the hydrophobicity of the biomaterials surface used.

A new method for in vivo evaluation of biofilms on surface-modified silicone rubber voice prostheses.

A new method is presented that permits a rapid and accurate in vivo evaluation of biofilm formation on surface-modified silicone rubber voice prostheses. The method is based on partial modification of a Groningen button voice prosthesis by exposing half of the prosthesis to an argon plasma. This results in one side of the prosthesis becoming hydrophilic while leaving the unmodified side hydrophobic as a control. Modified prostheses were placed in patients for an evaluation period of approximately 4 weeks. Despite making the silicone rubber surface hydrophilic, biofilm formation was stimulated when compared to unmodified, hydrophobic silicone rubber. Findings show that biofilm formation on voice prostheses is influenced by hydrophobicity of a silicone rubber surface. The method of partial surface modification used was seen to be suitable for demonstrating such influences regardless of nutrition and other variations in the patient's lifestyle. Microbiological analysis of the biofilms on both sides of the prosthesis valve did not show any changes in microbial composition, with Candida albicans, streptococci and staphylococci being the most commonly isolated strains.

Biodeterioration of medical-grade silicone rubber used for voice prostheses: a SEM study

Silicone voice prostheses used for rehabilitation of speech after total laryngectomy are inserted in an non-sterile habitat. Deposits on explanted Groningen Button voice prostheses revealed a biofilm, due to heavy colonization of the silicone surface by bacteria and yeasts. Furthermore, it was demonstrated by scanning electron microscopy on sectioned expiants that the silicone material was deteriorated by filamentous and vegetative yeast cells. The different expiants showed a variety of sharp-edged, discrete yeast colonies. The yeasts grew just under the silicone surface and up to 700 μm into the silicone material. Finally, nine different types of defects in the silicone material created by the yeasts are described. This deterioration of the silicone by yeasts seems to be the main reason for the failure and the frequent replacement of the prostheses. The mechanisms of silicone deterioration are still hypothetical.

Clinical experience with the low-resistance Groningen button.

Since its introduction in 1980, the standard Groningen button prosthesis has been of proven value for post-laryngectomy voice rehabilitation. Its relatively high airflow resistance has, however, been the cause of failure in achieving good post-laryngectomy tracheoesophageal shunt speech in some patients. The low-resistance Groningen button (LRGB) was therefore designed, thus reducing airflow resistance by 50% when compared to the standard device. The clinical performance of the LRGB, and the effect of prophylactic amphotericin, was assessed in 32 patients. The device lifetime, intratracheal phonatory pressures and patients' subjective acceptances of the prosthesis were recorded. Present findings showed that the majority of the patients preferred the LRGB as it required less effort to operate than the standard device. The intra-tracheal phonatory pressure was found to increase with time, but this change was prevented with the prophylactic use of amphotericin to inhibit concurrent colonization by Candida spp, which also helped to prolong the prosthesis lifetime.

Aerodynamic Properties of the Low-Resistance Groningen Button

Shunt tracheoesophageal speech is currently the most successful form of voice and speech rehabilitation in laryngectomees. Insertion of valve prostheses into the tracheoesophageal shunts has overcome drawbacks caused by stenosis of the shunt and aspiration. In 10 years of satisfactory results with the standard Groningen button valve prosthesis, the overall concept of this device has proved its value. The airflow resistance, however, is relatively high, so that a low-resistance device has been developed without changing the favorable characteristics of the standard device. The design of this low-resistance Groningen button is described. The airflow resistances of the standard and low-resistance Groningen buttons have been measured and compared. The airflow resistance of the low-resistance Groningen button is also compared with the reported airflow resistances of various other valve prostheses.

Surgical and prosthesis-related complications using the Groningen button voice prosthesis

Prosthesis-assisted tracheoesophageal speech has advanced speech rehabilitation appreciably. However, the surgical technique and the use of a prosthesis may give rise to complications. In a retrospective study on 132 consecutive patients rehabilitated with a Groningen button voice prosthesis, the complications were assessed, the average follow-up being 21 months. Surgical complications were not observed. Prosthesis-related complications, which were encountered in 28%, were all of a minor nature and mainly consisted of granulation formation and hypertrophic scarring; these appeared to be easily treatable. The complications found were few and insignificant in comparison with reports in the literature. This may be attributed to the uncomplicated surgical procedure for the insertion of the Groningen button. Moreover, the prosthesis is self-retaining and requires hardly any care from the patient. Permanent removal of the prosthesis usually requires surgical closure, which is a simple procedure performed under local anaesthesia.

Care of Tracheoesophageal Voice Prostheses-Reply

<i>In Reply</i>.—We thank Dr Modica for his comments and appreciate the opportunity to respond. There seem to be some matters that require clarification. First of all, we would like to stress the fact that<i>Candida</i>colonization is not limited to the Groningen button voice prosthesis, but can be observed on all voice prostheses that are made of silicone material.^1-3Dr Modica suggests the removal and cleansing of a prosthesis once or twice weekly to prevent fungal colonization. We, however, doubt the effectiveness of such a procedure, because a recent article²mentions fungal growth on prostheses as early as one day following placement! The same article confirms our experience that once the fungi have adhered to the silicone it is almost impossible to remove them without damaging the silicone material itself. A voice prosthesis can be easily damaged by an overly thorough cleaning procedure, especially when a lowpressure