Preclinical Validation of a Novel Device Designed to Reduce Biofilms on Percutaneous Osseointegrated Abutments.

AIM: To assess the efficacy of a prototype cleaning device in removing biofilm from skin-penetrating abutments. BACKGROUND: Adverse skin reactions around percutaneous osseointegrated implants have been linked to poor hygiene and infection. A cleaning device made from open-cell polyfoam has been developed to facilitate manual cleaning of abutments by the patient. METHODS: Serratia biofilm was grown on clean and sterile conical bone-anchored hearing system abutments including both pre-2007 (straight sided) and post-2007 (conical-sided) designs. Eighteen were photographed and then subjected to cleaning using a toothbrush or the cleaning device soaked in water or a proprietary mouthwash. Biofilm on a further group of 10 conical abutments was recorded using a scanning electron microscope before and after cleaning with the test device soaked in water. Quantitative analysis of the efficiency of the cleaning was made using image analysis. RESULTS: Removal of biofilm using a dry or wet toothbrush was not as effective as cleaning with the device. In 10 cases subjected to image analysis, approximately 90% of the biofilm was removed from the top third of the abutments, 85% from the middle third, and 48% from the basal third. CONCLUSION: The cleaning device is effective in removing most biofilm from the test abutments and represents a significant improvement in comparison with traditional methods such as a toothbrush.

The clinical outcome and microbiological profile of bone-anchored hearing systems (BAHS) with different abutment topographies: a prospective pilot study.

PURPOSE: In this prospective clinical pilot study, abutments with different topologies (machined versus polished) were compared with respect to the clinical outcome and the microbiological profile. Furthermore, three different sampling methods (retrieval of abutment, collection of peri-abutment exudate using paper-points, and a small peri-abutment soft-tissue biopsy) were evaluated for the identification and quantification of colonising bacteria. METHODS: Twelve patients, seven with machined abutment and five with polished abutment, were included in the analysis. Three different sampling procedures were employed for the identification and quantification of colonising bacteria from baseline up to 12 months, using quantitative culturing. Clinical outcome measures (Holgers score, hygiene, pain, numbness and implant stability) were investigated. RESULTS: The clinical parameters, and total viable bacteria per abutment or in tissue biopsies did not differ significantly between the polished and machined abutments. The total CFU/mm2 abutment and CFU/peri-abutment fluid space of anaerobes, aerobes and staphylococci were significantly higher for the polished abutment. Anaerobic bacteria were detected in the tissue biopsies before BAHS implantation. Anaerobes and Staphylococcus spp. were detected in all three compartments after BAHS installation. For most patients (10/12), the same staphylococcal species were found in at least two of the three compartments at the same time-point. The common skin coloniser Staphylococcus epidermidis was identified in all patients but one (11/12), whereas the pathogen Staphylococcus aureus was isolated in five of the patients. Several associations between clinical and microbiological parameters were found. CONCLUSIONS: There was no difference in the clinical outcome with the use of polished versus machined abutment at 3 and 12 months after implantation. The present pilot trial largely confirmed a suitable study design, sampling and analytical methodology to determine the effects of modified BAHS abutment properties. LEVEL OF EVIDENCE: 2. Controlled prospective comparative study.

Diseño y evaluación de las propiedades antibacterianas de un prototipo de molde de audífono que incorpora cobre en su manufactura / Design and evaluation of antibacterial properties of a prototype of earmold with copper incorporated in the manufacture

Introducción: La otitis externa infecciosa es una consulta otorrinolaringológica frecuente en usuarios de audífonos. Las propiedades antibacterianas descritas del cobre, han motivado el desarrollo de aplicaciones clínicas de este metal. Objetivo: Evaluar la capacidad antibacteriana de moldes de audífonos manufacturados con polímeros sensible a luz UV, silicona y acrílico que incorporan cobre metálico, en un sistema experimental in vitro. Material y método: Se diseñaron moldes de audífonos con y sin cobre, que fueron inoculados con distintas concentraciones de microorganismos (S aureus y P aeruginosa), para luego determinar el porcentaje de adherencia bacteriana a distintos tiempos de contacto (4, 8 y12 horas). Resultados: Existió reducción significativa en la adhesión bacteriana a los moldes con cobre respecto a aquellos sin cobre, independiente del material, del tipo de microorganismo y del inóculo bacteriano. Discusión: La disminución en la adherencia bacteriana en los prototipos con cobre, puede atribuirse a su actividad inhibitoria sobre los microorganismos en función de su concentración y el tiempo de contacto, ejerciendo su efecto por difusión a través de los distintos materiales. Conclusión: Con estos resultados, se hace necesario el desarrollo de estudios clínicos enfocados en comprobar si el uso de audífonos con cobre disminuyen las otitis externas de origen infeccioso.

Introduction: External otitis of infectious etiology among hearing aid users is a common motive of otolaryngology consultation. Antibacterial properties described copper, they have motivated the development of clinical applications of this metal. Aim: Evaluate the antibacterial capacity of copper-based ear molds manufactured with different materials such UV sensitive polymers, silicone and acrylic incorporating metallic copper, in an experimental system in vitro. Material and method: Ear molds with and without copper, were inoculated with different concentrations of microorganisms (S aureus and P aeruginosa) and determine the percentage of bacterial adherence to different contact times (4-8 and 12 hours). Results: There was significant reduction in bacterial adhesion to copper molds than those without copper, independent of the material, the type of microorganism and the bacterial inoculum. Discussion: The decrease in bacterial adherence on prototypes with copper, can be attributed to inhibitory activity on microorganisms depending on their concentration and contact time, exerting its effect by diffusion through the various materials. Conclusion: With these results, is necessary the development of clinical studies focused on checking whether the use of hearing aids with copper decreases external otitis of infectious origin.

External auditory canal microbiology and hearing aid use.

OBJECTIVE: The aim of this study was to determine the presence and nature of bacterial flora on hearing aids and the ears of this population. We wonder if the microbiology of the ears with hearing aid wearing differs from the other ear. SETTING: Tertiary referral center. DESIGN: A prospective, clinical study. SUBJECTS AND METHODS: Three samples were taken, one from the surface of the hearing aid's ear mold; one from the hearing aid-wearing ear canal and the last one from the ear without hearing aid. Samples were cultured to determine qualitatively and quantitatively the pathogenic microorganisms present. RESULTS: A total of 123 samples, obtained from 41 hearing aid users, were analyzed. Methicillin-resistant coagulase-negative staphylococci, methicillin-susceptible Staphylococcus aureus, methicillin-resistant S. aureus, Pseudomonas aeruginosa, Escherichia coli, Acinetobacter species, Staphylococcus auricularis, and Stenotrophomonas maltophilia were identified organisms. CONCLUSIONS: We identified unexpected microorganisms both on hearing aids and hearing aid using ears. This study demonstrates that using hearing aid alters the ear canal flora. To avoid otitis externa, it is important to use an appropriate hygiene routine to clean and disinfect hearing aids and ear molds.

Biofilm formation on bone-anchored hearing aids.

OBJECTIVE: To investigate microbiological biofilm contamination of retrieved bone-anchored hearing aids. MATERIALS AND METHODS: Nine failed, retrieved bone-anchored hearing aids and 16 internal screws were examined by scanning electron microscopy. A fixture from a failing implant, which had been removed and disassembled under aseptic conditions, was cultured. Finally, an internal screw from a new, unimplanted fixture was examined by scanning electron microscopy. RESULTS: Debris was seen on the fixture and abutment of all bone-anchored hearing aids, and on the heads of the 16 internal screws. On eight screws, biofilm extended down the shaft to the threads, where it was several micrometres thick. Culture of a failing fixture yielded staphylococcus. The new, unimplanted fixture internal screw showed evidence of scratching and metallic debris on the threads, which may interfere with close fitting of the screw and subsequently facilitate microleakage. CONCLUSION: There may be a link between internal microbial contamination and failure of bone-anchored hearing aids.

Study of bacterial flora in children's with hearing aid earmoulds in Ahvaz, Iran.

The aim of this study was to determine the presence and nature of bacterial flora on hearing aids earmoulds in a children's population. The study population consisted of 119 children referred to Imam Ali and Rudaky Schools in Ahvaz, Iran. Three samples were taken from surface of hearing aids earmoulds; canal in hearing aid wearers and ear without hearing aids earmoulds. The samples were cultured directly onto blood agar and MacConkey agar plates. According to preliminary examination, necessary standard biochemical tests were performed on grown bacteria and the organisms were identified as per standard identification criteria. Totally, 66 samples (61.1%) from hearing aids earmoulds and 124 samples (52.1%) from both ear canal without hearing aids earmoulds were culture positive, which 73 (58.9%) and 51 (41.1%) were from right and left ears, respectively. The majority of isolated bacteria from earmoulds were Coagulase-Negative Staphylococci (CNS) 40 (60.6%) and Polybacterial flora 14 (21.2%) and the least isolated bacteria were Pseudomonas aeruginosa and Staphylococcus aureus. In conclusion, although the majority of isolated bacteria were common normal flora of the ear, however a few pathogens were isolated as well. So, it is very important to educate the people with hearing aids earmoulds about proper cleaning and disinfection procedure to prevent any serious ear canal infection.

Prospective study of the microbiological flora of hearing aid moulds and the efficacy of current cleaning techniques.

INTRODUCTION: Wearing hearing aid earmoulds has been implicated as a predisposing factor in the development of chronic otitis externa. Audiologists come into contact with a large number of hearing aid earmoulds and these could potentially harbour pathogenic micro-organisms, with the risk of subsequent cross infection. Cleaning with dilute alcohol is widely used in an attempt to break the chain of infection. OBJECTIVE: To determine the presence and nature of microbial flora on hearing aid earmoulds and the efficacy of cleaning methods used to prevent cross infection. SETTING: Secondary health care within the audiology department of Addenbrooke's Hospital, Cambridge, UK. DESIGN: A prospective, observational study. METHODS: Hearing aid earmoulds were swabbed before and after cleaning. Samples were cultured to determine qualitatively and quantitatively the microbiological flora present before and after cleaning. RESULTS: Twenty out of 21 (95 per cent) earmoulds had microbes present and, of these, 19/20 (95 per cent) had a polymicrobial profile. Coagulase negative staphylococci and diphtheroids were the most frequent microbial isolates, but pathogenic bacteria and fungi were also demonstrated on earmoulds both before and after cleaning. CONCLUSIONS: The polymicrobial flora, including recognized pathogens, that colonizes earmoulds may lead to chronic otitis externa. Cleaning with 70 per cent alcohol solution was ineffective, in particular for pathogenic fungi on earmoulds.