An unusual case of Mycobacterium chelonae in contact lens solution

Abstract

Importance: Microbial keratitis is an increasing complication amongst contact lens wearers. In the absence of positive cultures, there should be a high index of suspicion for uncommon pathogens including acanthamoeba, herpes simplex, fungi and mycobacteria. Our unique case highlights mycobacteria as serious a pathogen which requires aggressive therapy. Successful treatment of mycobacteria could result in good visual potential. Observations: We describe an original case of presumed Mycobacterium chelonae infection and management in an elderly contact lens wearer with a protracted clinical course of bilateral non-healing epithelial defects. The patient initially did not reveal she was a contact lens wearer. She later confessed to washing contact lens with domestic tap water, but later changed this practice by using a contact lens disinfecting solution. Inspection of her contact lens solution revealed expiry 3 years earlier, from which Mycobacterium chelonae was eventually isolated. Resolution of her keratitis only occured after triple antibiotic therapy of topical amikacin, moxifloxacin and azithromycin supported by oral clarithromycin. She later underwent penetrating keratoplasty in both eyes, with good visual outcome. Conclusions and relevance: To the best of our knowledge, this is the first reported case of bilateral Mycobacterium chelonae keratitis arising from contaminated CL solution. This case illustrates the importance of considering Mycobacterium in the differential diagnoses when treating non healing keratitis. It is important to enquire about contact lens wear and hygiene in all keratitis cases, regardless of patient age. There is a need to create public awareness regarding the potential serious risk of CL wear and safe CL practice that includes monitoring by eye care professionals.