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Letters to the Editor

A Successful Staged Approach to Management of Mycobacterium fortuitum Cochlear Implant Infection

Foley, David A. MMED; McLeod, Charlie MBBS; Rodrigues, Stephen MBBS; Yeoh, Daniel K. MBBS

Author Information
The Pediatric Infectious Disease Journal: January 2021 - Volume 40 - Issue 1 - p e47-e48
doi: 10.1097/INF.0000000000002956
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To the Editors:

Cochlear implant (CI) infections at the site of the internal receiver-stimulator component are uncommon.1 Optimal management is unclear, including the role of surgical intervention,1 especially in the setting of nontuberculous mycobacterial infection.2,3 We report the successful treatment of a complex CI infection with Mycobacterium fortuitum, with preservation of hearing, using prolonged antimicrobial therapy and a staged surgical approach.

A 12-year-old female, with longstanding bilateral CIs, presented with a 6-week history of right postauricular swelling and skin breakdown, with minimal response to empiric antibiotics. At presentation, there was a tissue defect overlying the right CI receiver extending to the device (Fig. 1). She was admitted to hospital for surgical wound debridement (day 1). Cultures grew Staphylococcus. epidermidis (susceptible to vancomycin, doxycycline, rifampicin and ciprofloxacin); oral rifampicin and doxycycline were commenced (day 3). On day 6, in the context of persistent wound discharge, the receiver was removed and the array retained in the cochlea. Tissue samples from the receiver bed grew M. fortuitum and Candida parapsilosis. Antimicrobial therapy was adjusted accordingly to intravenous meropenem and oral azithromycin, doxycycline, ciprofloxacin and fluconazole (day 16). A positron emission tomography/computed tomography and bone scan were performed to characterize the extent of the infection did not demonstrate bony involvement. M. fortuitum was subsequently reported as susceptible to amikacin (<1 μg/ml), ciprofloxacin (≤0.12 μg/ml), doxycycline (0.25 μg/ml) and linezolid (8 μg/ml), intermediate to cefoxitin (32 μg/ml) and imipenem (8 μg/ml) and resistant to clarithromycin (8 μg/ml).4

FIGURE 1.
FIGURE 1.:
Image of right postauricular region at presentation; overlying the right Cochlear implant receiver.

The wound healed slowly by secondary intention; antibiotics were rationalized to doxycycline, ciprofloxacin and fluconazole (day 30). She developed significant phototoxicity attributed to doxycycline, managed with barrier protection and sunscreen. Her corrected QT interval remained normal throughout treatment. After 6 months of therapy, the retained array was removed and an interval spacer placed in the cochlea (day 219); samples were culture negative for fungi and mycobacteria. A new implant was placed 6 weeks later (day 275); intraoperative samples were again culture negative for fungi and mycobacteria. She remained well postoperatively and antibiotics were ceased 6 weeks following reimplantation (day 317). She remains well at 6 months follow-up.

The pathogens detected likely reflect external contamination of an exposed CI receiver. Management of Mycobacterium spp. CI infections is challenging. Complete explantation and antimicrobial therapy is arguably the simplest approach, but at the cost of hearing capacity.2 The patient’s age and dependence on CI (70% of hearing capacity) favored an approach involving partial explantation and retention of implant array in the first instance with a view to reimplantation as previously described.3 The array was retained as an interval without an array in the cochlea may increase the risk of cochlear osteogenesis, precluding the possibility of reinsertion. Due to concerns about biofilm,5 an interval procedure with repeat sampling, removal of the array and placement of a temporary spacer (to retain patency) were undertaken before implantation of a new CI.

This case supports a staged approach to manage nontuberculous mycobacterial CI device infections, which is safe, feasible and associated with clinical resolution.

David A. Foley, MMED
Charlie McLeod, MBBS
Infectious Diseases Department, Perth Children’s Hospital, Perth, Australia
Stephen Rodrigues, MBBS
Ear, Nose, Throat and Otolaryngology Department, Perth Children’s Hospital, Perth, Australia
Daniel K. Yeoh, MBBS
Infectious Diseases Department, Perth Children’s Hospital, Perth, Australia

REFERENCES

1. Vila PM, Ghogomu NT, Odom-John AR, et al. Infectious complications of pediatric cochlear implants are highly influenced by otitis media. Int J Pediatr Otorhinolaryngol. 2017;97:76–82.
2. Lodhi F, Coelho DH. Non-tuberculous mycobacterial cochlear implant infection: an emerging pathogen. Cochlear Implants Int. 2015;16:237–240.
3. Anderson JH, Boyce TG, Wengenack NL, et al. Mycobacterium abscessus infection of a cochlear implant insertion site. Int J Pediatr Otorhinolaryngol Extra. 2013;8:122–124.
4. Woods GL, Brown-Elliott BA, Conville PS, et al. Susceptibility Testing of Mycobacteria, Nocardiae, and Other Aerobic Actinomycetes. 3rd edClinical Laboratory Standards Institute, 2018.
5. Im GJ, An YS, Choi J, et al. Analysis of bacterial biofilms on a cochlear implant following methicillin-resistant Staphylococcus aureus infection. J Audiol Otol. 2015;19:172–177.
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