Abstract
Recalcitrant chronic infections of implanted medical devices are often linked to the presence of biofilms. The prevention and treatment of medical device-associated infections is a major source of antibiotic use and driver of antimicrobial resistance globally. Lowering the incidence of infection in patients that receive implanted medical devices could therefore significantly improve antibiotic stewardship and reduce patient morbidity. Here we determined if modifying the design of an implantable medical device to reduce bacterial attachment, impacted the incidence of device-associated infections in clinical practice. Since the 1980s cochlear implants have provided long-term treatment of sensorineural hearing deficiency in hundreds of thousands of patients world-wide. Nonetheless, a relatively small number of devices are surgically explanted each year due to unresolvable infections. Features associated with the accumulation of bacteria on the Cochlear™ Nucleus® CI24RE™ model of cochlear implant devices were identified using both in vitro bacterial attachment assays and examination of explanted devices. Macro-scale design modifications that reduced bacterial attachment in vitro were incorporated into the design of the CI500™ and Profile™ series of Nucleus implant. Analyses of mandatory post-market vigilance data of 198,757 CI24RE and 123,084 CI500/Profile series implantation surgeries revealed that these design modifications correlated with significantly reduced infection rates. This study demonstrates that a design-centric approach aimed at mitigating bacterial attachment was a simple, and effective means of reducing infections associated with Cochlear Nucleus devices. This approach is likely to be applicable to improving the designs of other implantable medical devices to reduce device-associated infections.
Highlights
We found that bacterial biomass was located on the ECE plate in all four CI24RE devices associated with infections and on the silicone edges of the magnet pocket in three of the four devices (Figure 1B)
Infections associated with implanted medical devices are often recalcitrant to antimicrobial therapy due to the presence of biofilms [4] and persister cells [3] that have elevated resistances to antibiotics and immune clearance
The overuse of antibiotics to treat device-associated infections is associated with increasing levels of antimicrobial resistance among bacterial pathogens [13]
Summary
Over half of healthcare-associated infections can be attributed to implanted medical devices occurring in 0.08–50% for the most common implant types depending on the implant site, how long the device is implanted, patient comorbidities, or other risk factors with the highest rates of infection associated with urinary and cardiac devices [1,2]. Recalcitrant chronic infections of implanted medical devices. Microorganisms 2021, 9, 1809 are often linked to the presence of persister cells [3] and surface-attached communities of microorganisms called biofilms that have elevated resistances to antibiotics and the immune system [4]. Almost immediately after a medical device is implanted it becomes coated with a conditioning film comprised of host extracellular matrix, plasma proteins, and platelets which can serve as receptors for colonizing bacteria and fungi which adhere to the implant surface and establish biofilms [5]
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