Antibacterial Polysiloxane Polymers and Coatings for Cochlear Implants.

Within this study, new materials were synthesized and characterized based on polysiloxane modified with different ratios of N-acetyl-l-cysteine (NAC) and crosslinked via UV-assisted thiol-ene addition, in order to obtain efficient membranes able to resist bacterial adherence and biofilm formation. These membranes were subjected to in vitro testing for microbial adherence against S. pneumoniae using standardized tests. WISTAR rats were implanted for 4 weeks with crosslinked siloxane samples without and with NAC. A set of physical characterization methods was employed to assess the chemical structure and morphological aspects of the new synthetized materials before and after contact with the microbiological medium.

Use of negative pressure wound therapy to treat a cochlear implant infection around the auricle: a case report.

Although negative pressure wound therapy (NPWT) is widely used, its application to the head and neck region remains challenging due to anatomical complexities. This report presents the case of a female patient presenting with mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes, uncontrolled diabetes and severe bilateral sensorineural hearing loss. The patient had undergone cochlear implant surgery and five months later the wound was infected with methicillin-resistant Staphylococcus aureus (MRSA). NPWT was started shortly after removing the internal receiver and was stopped 11 days later. NPWT helped in controlling infection and led to a successful wound closure. In this case, NPWT was effective in treating infectious wounds around the auricle after cochlear implant surgery. Declaration of interest: The authors have no financial support for this article and no conflict of interest directly relevant to the content of this article.

Microflora of Retained Intracochlear Electrodes from Infected Cochlear Implants.

Objectives Cochlear implant infections may be refractory to medical management and require device removal with subsequent reimplantation. During device removal, the intracochlear electrode array is commonly left in place to prevent obliteration of the cochlear lumen. If the electrode is colonized with pathogens, this risks contaminating the replacement implant. In this study, we compare the microorganisms detected on infected cochlear implants against those on the retained electrode using culture and microbial gene-sequencing techniques. Study Design Prospective single-cohort study. Setting Tertiary medical center. Subjects and Methods Six patients with refractory cochlear implant infections had the receiver-stimulator and extracochlear electrode removed to facilitate treatment of the infection. The intracochlear electrode was removed at (delayed) reimplantation. Implant specimens were analyzed by microbial culture and 16S DNA gene sequencing. Results Staphylococcus aureus was the organism most commonly identified. None of the 6 patients' intracochlear electrodes yielded microbes by culture. Two intracochlear electrodes revealed bacterial species, and 1 revealed fungal species by gene sequencing. There was no correlation between the microbes on the infected extracochlear implants and the retained intracochlear electrodes. All subjects underwent reimplantation after resolution of their infections. One of 6 subjects developed a second infection after reimplantation, with S aureus in the primary and secondary infections. Conclusions The intracochlear electrodes of infected cochlear implants carry a low microbial burden. Preserving intracochlear electrodes upon removal of infected cochlear implants appears to carry a low risk of contaminating a replacement cochlear implant.

Recurrent cochlear implant infection treated with exteriorization and partial mastoid obliteration.

OBJECTIVE AND IMPORTANCE: Preoperative chronic otitis media (COM) is a risk factor for postoperative infection after cochlear implantation (CI), but its management varies by surgeon. Our case highlights a strategy for implant preservation in a patient with a history of recurrent cochlear implant infection. CLINICAL PRESENTATION: A 70-year-old woman with a history of chronic lymphocytic leukemia presented in 2005 with bilateral COM and sensorineural hearing loss meeting CI candidacy. Four months after left mastoid obliteration with abdominal fat graft and external auditory canal closure, a left CI was placed. Subsequent postauricular cellulitis resolved with oral antibiotics. A similar two-stage CI was performed on the right without complication. During the following year, numerous left-sided infections and fluid collections developed but were treated unsuccessfully with intravenous (IV) antibiotics and operative debridement. With concern for biofilm colonization, the implant was explanted and the electrode left in the cochlea. After reimplantation in 2010, infections resumed despite long-term IV antibiotics and incision and drainage. Intervention and technique In 2012, the left mastoid cavity was exteriorized and converted to standard canal wall-down anatomy. Bone pâté was placed over the electrode, followed by cadaveric acellular dermis and a split-thickness skin graft. After more than 2 years, her better-performing CI remains infection-free. CONCLUSION: After 6 years of postoperative infections unresponsive to aggressive medical management, surgical interventions, and period of device removal, our patient's infections resolved after mastoid exteriorization and multilayered protection of the electrode. This strategy may enable implant preservation in patients with recurrent post-CI infection in an obliterated cavity.

Infected cochlear implant after large-volume nasal irrigation.

OBJECTIVE: A patient with a well-healed, functional cochlear implant (CI) experienced a CI and mastoid infection shortly after initiating large-volume nasal irrigations after sinus surgery. The goal of this report is to bring attention to a rare complication and to question if large-volume nasal irrigation is safe in CI recipients. PATIENTS: Single patient at a tertiary care hospital. INTERVENTIONS: A CI recipient began using large-volume nasal irrigations with saline and budesonide after undergoing sinus surgery. MAIN OUTCOME MEASURES: CI infection and mastoiditis. RESULTS: Two weeks after starting nasal irrigations, the patient presented with mastoiditis and CI infection. Mastoid and intranasal middle meatal cultures both grew Group A streptococcus. CONCLUSION: Large-volume nasal irrigations may be related to our patient's CI infection, ultimately leading to explantation. Though a causal relationship cannot be definitively proven, awareness of this potential safety issue should be disseminated.

Preliminary results of a novel quorum sensing inhibitor against pneumococcal infection and biofilm formation with special interest to otitis media and cochlear implantation.

The purpose of the study is to assess the effect of a novel quorum sensing inhibitor (QSI), coded as 'yd 47', against otitis media and biofilm formation on Cochlear implants (CIs). Small pieces cut from cochlear implant were implanted under the skin in the retroauricular area on both sides of four guinea pigs. The implant pieces in the study and control sides were implanted in Streptococcus pneumoniae strain solution and saline, respectively. The right and left middle ears were also instilled with a solution containing pneumococci and saline, respectively. The animals were only given an intraperitoneal 'yd 47' twice daily for three months to be assessed later with electron microscopy. Clinical examination with palpation, inspection and otoscopy did not reveal any sign of implant infection or otitis media. In the study and control implant materials, soft tissues around the implant and tympanic membranes, there was no biofilm formation by pneumococci. Contamination by various cells and some rod-shaped bacteria (not diplococcic) were seen in some of the materials. In conclusion, the novel QSI seems promising in the prevention of otitis media and biofilm formation on CIs by pneumococci.

Cochlear implants and bacterial meningitis: A speech recognition study in paired samples

Introduction: Cochlear implants may guarantee sound perception and the ability to detect speech at a close-to-normal hearing intensity; however, differences have been observed among implantees in terms of performance on discrimination tests and speech recognition. Objective: To identify whether patients with post-meningitis deafness perform similarly to patients with hearing loss due to other causes. Method: A retrospective clinical study involving post-lingual patients who had been using Nucleus-22 or Nucleus-24 cochlear implants for at least 1 year. These patients were matched with respect to age (± 2 years), time since the onset of deafness (± 1 year), and the duration of implant use with implant users who had hearing loss due to other causes. Speech perception was assessed using the Portuguese version of the Latin-American Protocol for the Evaluation of Cochlear Implants. Results: The sample consisted of 52 individuals (26 in each of the 2 groups). The post-meningitic group had a median of 18.5 active electrodes. The group with hearing loss due to other causes had a median of 21, but no significant statistical difference was observed (p = 0.07). The results of closed- and open-set speech recognition tests showed great variability in speech recognition between the studied groups. These differences were more pronounced for the most difficult listening tasks, such as the medial consonant task (in the vowel-consonant-vowel format). Conclusion: Cochlear implant recipients with hearing loss due to bacterial meningitis, who had been using the device for 1 year performed more poorly on closed- and open-set speech recognition tests than did implant recipients with hearing loss due to other causes...

Case report - biofilm infection of a cochlear implant.

One of the most dreaded complications after cochlear implantation is infection. These infections are a challenge due to lack of any data regarding optimal methods of investigation and management. More often than not, these patients have to undergo explantation and revision surgery. This paper presents a case report and literature review which focuses on the role of antibiotics and the need for early explantation in most biofilm-related infections of cochlear implants.

Staphylococcus aureus biofilm formation on an explanted cochlear implant demonstrated using an ultrasonication technique.

RELEVANCE: Biofilm forming microorganisms are responsible for the infection of a number of different indwelling medical devices including cochlear implants. The current definitive technique for proving biofilm infection is the use of scanning electron microscopy that is expensive and of limited availability. CLINICAL PRESENTATION: A persistently infected cochlear implant was explanted. At operation it was surrounded by a fibrous capsule containing a glue-like substance, characteristic of biofilm formation that yielded Staphylococcus aureus after ultrasonication of the device. TECHNIQUE: The explanted cochlear implant was placed in a nutrient broth in an ultrasonic water bath. The implant was ultrasonicated for 5 minutes and the broth cultured on blood agar, incubated aerobically and anaerobically for 48 hours, and then incubated in air on Maconkey agar for 24 hours. This produced a heavy, confluent growth of S. aureus, in contrast to previous aspirates from a blister that lay over the infected implant that grew a coliform organism and Pseudomonas sp. CONCLUSION: Ultrasonication is a widely available and relatively inexpensive technique that can be used to improve the recovery of biofilm-associated organisms from explanted cochlear implants.

Eradicating chronic ear, nose, and throat infections: a systematically conducted literature review of advances in biofilm treatment.

OBJECTIVE: Bacteria can grow as individual, planktonic organisms or as complex biofilm communities that are more resistant to treatment. This review was designed to systematically search to identify recent laboratory studies on eradication of biofilms in otolaryngologic infections to highlight promising advances in biofilm treatment. DATA SOURCES: A systematic electronic literature search of Medline/PubMed, CINHAL, and Web of Science was conducted for articles describing the treatment of biofilm infections in ear, nose, and throat (ENT) diseases through March 2010. English-language articles and articles with an English abstract that focused on biofilm treatment were considered for review. REVIEW METHODS: Each included article was reviewed by one of the authors for study design, treatment intervention, and outcome. Data from in vitro and animal studies were considered separately from human studies. RESULTS: A total of 30 articles were identified for this review, including 5 studies that included a human treatment component. In general, antibiotics were relatively ineffective for eradicating biofilm infections. Markedly higher antibiotic dosages were required to reduce biofilm presence compared with doses that were effective in eradicating planktonic bacteria. Mupirocin irrigation, gentian violet, and thiamphenicol glycinate acetylcysteine effectively eradicated biofilms. Physical disruption, surfactants, and probiotics were also shown to be beneficial in both nonhuman and human studies. CONCLUSION: Eradicating ENT biofilms is difficult when treating single-organism or mixed flora biofilms. Antibiotic therapy is often ineffective against biofilms, and clinical treatment may need to focus on nonantibiotic therapies that reduce, disrupt, or eradicate ENT biofilms.

Current status of bacterial meningitis after cochlear implantation.

Meningitis after cochlear implantation continues to be a concern. Recent studies and anecdotal reports support the belief that intracochlear trauma, lack of appropriate immunizations, and a previously used dual-component electrode predispose patients to a higher rate of contracting meningitis. In addition, a history of meningitis, cochlear dysplasia, and certain variations of surgical technique such as the cochleostomy, very young age, immunocompromise, and the presence of neural prostheses such as shunts, are all potentially predisposing factors. Because many of these factors are beyond our control, there is likely to be an inevitable baseline incidence of meningitis, perhaps related to the underlying deafness, but by controlling other factors, we can hope to minimize the incidence. Despite the efforts of multiple individuals and organizations, there continue to be new cases of meningitis, including a small number of fatalities, each year. There is recent evidence that a sizeable percentage of children with implants have not been vaccinated as suggested by governmental agencies, otolaryngologic societies, implant manufacturers, and many cochlear implant centers. Clearly, efforts must be made to ensure age-appropriate vaccination for all cochlear implant recipients.

Cochlear implants in children: surgical site infections and prevention and treatment of acute otitis media and meningitis.

The use of cochlear implants is increasingly common, particularly in children younger than 3 years. Bacterial meningitis, often with associated acute otitis media, is more common in children with cochlear implants than in groups of control children. Children with profound deafness who are candidates for cochlear implants should receive all age-appropriate doses of pneumococcal conjugate and Haemophilus influenzae type b conjugate vaccines and appropriate annual immunization against influenza. In addition, starting at 24 months of age, a single dose of 23-valent pneumococcal polysaccharide vaccine should be administered. Before implant surgery, primary care providers and cochlear implant teams should ensure that immunizations are up-to-date, preferably with completion of indicated vaccines at least 2 weeks before implant surgery. Imaging of the temporal bone/inner ear should be performed before cochlear implantation in all children with congenital deafness and all patients with profound hearing impairment and a history of bacterial meningitis to identify those with inner-ear malformations/cerebrospinal fluid fistulas or ossification of the cochlea. During the initial months after cochlear implantation, the risk of complications of acute otitis media may be higher than during subsequent time periods. Therefore, it is recommended that acute otitis media diagnosed during the first 2 months after implantation be initially treated with a parenteral antibiotic (eg, ceftriaxone or cefotaxime). Episodes occurring 2 months or longer after implantation can be treated with a trial of an oral antimicrobial agent (eg, amoxicillin or amoxicillin/clavulanate at a dose of approximately 90 mg/kg per day of amoxicillin component), provided the child does not appear toxic and the implant does not have a spacer/positioner, a wedge that rests in the cochlea next to the electrodes present in certain implant models available between 1999 and 2002. "Watchful waiting" without antimicrobial therapy is inappropriate for children with implants with acute otitis media. If feasible, tympanocentesis should be performed for acute otitis media, and the material should be sent for culture, but performance of this procedure should not result in an undue delay in initiating antimicrobial therapy. For patients with suspected meningitis, cerebrospinal fluid as well as middle-ear fluid, if present, should be sent for culture. Empiric antimicrobial therapy for meningitis occurring within 2 months of implantation should include an agent with broad activity against Gram-negative bacilli (eg, meropenem) plus vancomycin. For meningitis occurring 2 months or longer after implantation, standard empiric antimicrobial therapy for meningitis (eg, ceftriaxone plus vancomycin) is indicated. For patients with meningitis, urgent evaluation by an otolaryngologist is indicated for consideration of imaging and surgical exploration.

[Biomaterials in cochlear implants]. / Biomaterialien bei Cochlea-Implantaten.

Cochlear implants (CI) represent the "gold standard" for the treatment of congenitally deaf children and postlingually deafened adults. Thus, cochlear implantation is a success story of new bionic prosthesis development. Owing to routine application of cochlear implants in adults but also in very young children (below the age of one), high demands are placed on the implants. This is especially true for biocompatibility aspects of surface materials of implant parts which are in contact with the human body. In addition, there are various mechanical requirements which certain components of the implants must fulfil, such as flexibility of the electrode array and mechanical resistance of the implant housing. Due to the close contact of the implant to the middle ear mucosa and because the electrode array is positioned in the perilymphatic space via cochleostomy, there is a potential risk of bacterial transferral along the electrode array into the cochlea. Various requirements that have to be fulfilled by cochlear implants, such as biocompatibility, electrode micromechanics, and although a very high level of technical standards has been carried out there is still demand for the improvement of implants as well as of the materials used for manufacturing, ultimately leading to increased implant performance. General considerations of material aspects related to cochlear implants as well as potential future perspectives of implant development will be discussed.

Detection of bacteria in healthy middle ears during cochlear implantation.

OBJECTIVE: To assess whether free-living and/or biofilm bacteria are present in the putative sterile middle ear cavity before insertion of the electrode array during cochlear implantation. DESIGN: Prospective study. SETTING: Tertiary academic hospital. PATIENTS: The study included 45 healthy children (with or without a history of otitis media) undergoing cochlear implantation. INTERVENTIONS: Transmission electron microscopy or scanning electron microscopy was used to detect the presence of bacteria. MAIN OUTCOME MEASURE: Presence of both free-living bacteria and biofilm bacteria on the epithelial surface of biopsy specimens of middle ear mucosa. RESULTS: A majority of all mucosal specimens from clinically healthy tympanic cavities displayed inflammatory areas as well as dispersed, nonmatrix-enclosed bacteria. Also, rarely, fragments of biofilms were found. CONCLUSIONS: The presence of bacteria in the tympanic cavity, which is generally assumed to be sterile in healthy individuals, may provide an explanation for infectious complications after cochlear implantation. However, the possibility that the electrode array of a cochlear implant will actually become contaminated during insertion is unlikely because of the small amounts and dispersed presence of bacteria, which may account for the relatively low incidence of infectious complications after cochlear implantation.

Immuno-detection of Staphylococcus aureus biofilm on a cochlear implant.

CASE PRESENTATION: A 46-year-old man suffering from progressive deafness since childhood received a Clarion 90 K cochlear implant with the HiRes preformed electrode in his left ear in October 2006. A persistent Staphylococcus aureus infection failed to be treated with corticoids, amoxicillin/ clavulanate, ciprofloxaxin, and rifampin. The processor was removed on July 2007. INTERVENTIONS: The removed cochlear implant processor was treated with different reagents, with the aim of detecting a S. aureus and S. aureus biofilm: (1) fluorescein-coupled Fc of anti-human serum, (2) polyclonal anti-polysaccharide intercellular adhesion antibodies coupled to Alexa Fluor 568 goat anti-rabbit immunoglobulin (Ig)G, (3) crystal violet, (4) methylene blue, (5) acridine orange, (6) Gram stain, and (7) live/dead fluorescent stain. RESULTS: S. aureus and the major constituent of the S. aureus biofilm, the polysaccharide intercellular adhesion, were detected on the surface of the implant. S. aureus was isolated after a simple contact between the implant and a solid growth medium. The ability of the isolated S. aureus strain to produce biofilm in vitro was confirmed. INTERPRETATION: S. aureus biofilm was documented on the implant. Initial bacterial colonization could be related to the pocket of the removable magnet. Colonies of S. aureus without biofilm were found attached to the electrode wire. CONCLUSION: We report one case of a S. aureus biofilm infection documented on a cochlear implant, as assessed by immuno-microscopy. The biofilm was likely responsible for the persistent infection which manifested for many months after the implant surgery and could explain the unusual bacterial phenotypic resistance against administered antimicrobial agents.

Assessment of the protective effect of pneumococcal vaccination in preventing meningitis after cochlear implantation.

OBJECTIVES: To examine if a 23-valent pneumococcal capsular polysaccharide vaccine (PPV23) reduces the risk of meningitis in healthy rats after cochlear implantation. DESIGN: Interventional animal study. INTERVENTIONS: Thirty-six rats (18 immunized and 18 unimmunized) received cochlear implantations and were then infected with Streptococcus pneumoniae via 3 different routes (hematogenous, middle ear, and inner ear) in numbers sufficient to induce meningitis. RESULTS: The rats with implants that received PPV23 were protected from meningitis when the bacteria were delivered via the hematogenous and middle-ear routes (Fisher exact test P<.05). However, the protective effect of the vaccine in the rats with implants was only moderate when the bacteria were inoculated directly into the inner ear. CONCLUSIONS: Our animal model clearly demonstrates that immunization can protect healthy rats with a cochlear implant from meningitis caused by a vaccine-covered serotype. This finding supports the notion that all current and future implant recipients should be vaccinated against S pneumoniae.

The value of nuclear scans in cochlear implant infections.

We discuss the diagnostic value of nuclear scintigraphy in the management of infections after cochlear implantation. A 56-year-old female (Case 1) and a 46-year-old female (Case 2) developed complaints of diffuse headache, 4 and 5 months after cochlear implantation, without other signs of infection during examination, laboratorial testing and initial computed tomography. In Case 1 we performed a technetium 99 m-difosfate scintigraphy, which showed an increased uptake in the right petrosal bone, suggestive of chronic osteomyelitis. This case failed conservative treatment and underwent complete explantation, after which 67gallium-citrate single-photon emission computed tomography normalized during follow-up. In Case 2 inflammation at the site of the cochlear implant was confirmed by performing a positron emission tomography scan, which showed an increased uptake. Case 2 was treated successfully with antibiotics. Both have no signs of recurrent infection. Nuclear scintigraphy can be the single valuable tool in case of a late low-grade infection after cochlear implantation. Delayed low-grade chronic osteomyelitis of the petrosal bone is a rare but dramatic complication after cochlear implantation. It can develop with minimal signs of infection.

Experiencia latinoamericana con el implante coclear / Latin American experience with cochlear implant

Se pretende revisar la experiencia latinoamericana con el implante coclear. Para ello se envió un cuestionario a todos los grupos latinoamericanos de implante coclear. Las principales preguntas fueron: (1) tipo de implante; (2) técnica para colocar y fijar el implante, incisión y cierre; (3) migración, exposición y fallas; y (4) erosión de la piel e infección. Un total de 41 grupos participaron en el estudio. El número total de implantes fue de 3.773, representando el 92 por ciento de los casos latinoamericanos. De los 3.773 implantes, 5 eran prototipos experimentales por lo tanto 3.768 se consideraron para los cálculos. Las complicaciones fueron las siguientes: Migración: 13 casos (0,35 por ciento), relacionada principalmente a receptores cerámicos (p=0,016). Expulsión: 15 casos (0,4 por ciento), relacionados principalmente a implantes grandes (p=0,0103). Fallas de implantes secundarias a trauma: 18 casos (0,48 por ciento) (9 en implantes cerámicos y 9 en blandos). Falla espontánea: 86 casos (2,28 por ciento), 74/1.293 (5,72 por ciento) en cerámicos y 11/2.418 (0,45 por ciento) en blandos (p=0,0001). El implante más confiable fue el Nucleus 24, con una tasa de fallas de 0,3 por ciento. Infección: 26 casos (0,7 por ciento), sin relación significativa con tipo de implante. Se concluye planteando que complicaciones como migración, expulsión, inflamación de piel y fallas de implantes se relacionan principalmente con el tipo de implante. Técnica meticulosa más que abordajes específicos son la clave para evitar complicaciones. Los resultados latinoamericanos son comparables con los reportados recientemente en la literatura.

Bacterial biofilm formation on a human cochlear implant.

OBJECTIVE: To report the characteristics of a bacterial biofilm from the surface of a cochlear implant. BACKGROUND: Bacterial biofilm formation on implanted devices causes intractable infections and device extrusions necessitating device removal, with loss of function. More information is needed about biofilm characteristics and interactions with the implant surface before better treatments can be designed. STUDY DESIGN: A retrospective case review was combined with a descriptive histological study of the surface of an otologic device. METHODS: The receiver/stimulator device removed from a cochlear implant patient because of intractable infection and partial device extrusion was fixed and processed for microscopic examination. Its surface and the material present on its surface were analyzed using light and electron microscopy, focusing on surface texture, cell types, and bacteria species and extracellular polymeric substances present within the biofilm. RESULTS: Stereomicroscopic examination revealed extracellular polymeric substances, pinkish yellow in color, with spheres of uniform size scattered throughout, indicative of a biofilm containing Staphylococcus aureus. Biofilm density was greatest in depressions on the surface of the implant. Cross-sectional analysis revealed bacteria interspersed with polymorphonuclear leukocytes. Scanning electron microscopic examination demonstrated an amorphous layer of extracellular polymeric substances containing small filaments, bacteria, and inflammatory cells. Only Staphylococcus aureus was detected. CONCLUSION: Cochlear implant material can provide a surface for bacterial biofilm formation. Impressions can provide an environment conducive to biofilm establishment and growth, ultimately necessitating device removal, with loss of implant function. Biofilm characterization should aid in design of cochlear implant devices less susceptible to biofilm formation.

Biofilm: why the sudden interest?

In recent years there has been increasing interest in the role of biofilms in perpetuating the chronicity and severity of bacterial infections. Enter the word biofilm as a search criterion with PubMed (National Library of Medicine) and you will doubtless be surprised to recover over 4000 citations, with nearly 3000 registered since 2000. So why has there been such an explosion of interest in this phenomenon? This article seeks to provide a brief overview of the subject, with particular reference to the role that biofilms may have to play in otologic disease.