Cochlear implant is used for treating severe hearing loss in those who receive insufficient benefit from hearing aids. It was first commercialized at Melbourne University in 1977. With the switch to the multi-channel type, the ability of cochlear implants to restore hearing loss has improved even further. In addition, the effectiveness of binaural cochlear implants has recently been reported. However, such problems as infection due to the implant, as it is a foreign body, electrode migration, facial nerve paralysis and electrode abnormalities, may occur. According to a report by Ikeya, postoperative complications occurred in about 8.7% of cases and reoperation was necessary in about 3% of cases. Elsewhere, the most frequent complication, accounting for around 40%, was infection due to skin flaps. Infection occurred in 28 of 267 pediatric patients (under 20 years of age) who underwent cochlear implant surgery from 2000 to 2015 at our department. The causative organism was methicillin-resistant Staphylococcus aureus (MRSA) in 8 cases, Staphylococcus aureus in 7 cases, Corynebacterium sp. in 7 cases, Corynebacterium in 6 cases, coagulase-negative staphylococci (CNS) in 6 cases, Staphylococcus epidermidis in 2 cases, Moraxella sp. in 1 case, Pseudomonas aeruginosa in 1 case, and Candida parapsilosis in 1 case (including duplicate infections). Among the 8 cases with MRSA infection, 6 cases required removal of the cochlea. Other infections included cases of multiple infections (31 cases), including 2 of the 7 cases with Staphylococcus aureus infection and 1 of the 6 cases with corynebacterial infection. These results suggest that MRSA infection in cochlear implant wearers necessitates reoperation at a high rate. Herein, we present two representative cases of MRSA infection in detail and a retrospective review of 8 cases of MRSA infection encountered at our hospital.
