Endophthalmitis Caused by Nontuberculous Mycobacterium: Clinical Features, Antimicrobial Susceptibilities, and Treatment Outcomes

Purpose To report the clinical features, antibiotic susceptibilities and treatment outcomes in patients with endophthalmitis caused by nontuberculous mycobacterium. Design Noncomparative, consecutive case series. Methods Retrospective chart review between December 1990 and June 2014. Results In the 19 study patients, the clinical setting of endophthalmitis included post-cataract surgery (7/19, 36.8%), post-glaucoma implant (6/19, 31.6%), post-intravitreal injection (2/19, 10.5%), endogenous endophthalmitis (2/19, 10.5%), post-pars plana vitrectomy (1/19, 5.3%), and post-scleral buckle exposure (1/19, 5.3%). Chronic recurrent or persisting ocular inflammation was present in 15 of 19 patients (78.9%). The species isolated were Mycobacterium chelonae in 14 patients (73.7%), M fortuitum in 3 patients (15.8%), M triplex in 1 patient (5.3%), and M avium intracellulare in 1 patient (5.3%). Antibiotic susceptibilities to tested isolates were the following: amikacin (14/16; 87.5%) and clarithromycin (12/16, 75.0%). Intravitreal injections of amikacin (0.4 mg/0.1 mL) were given in 14 of 19 patients (73.7%) with an average of 7 injections per patient (range, 1-24 injections). Intraocular lens removal was performed for 6 of 7 patients (85.7%) with post-cataract surgery endophthalmitis. All the patients with glaucoma implant (6/6, 100%) underwent implant removal. At last follow-up, 6 of 19 patients (31.6%) had best-corrected visual acuity of 20/400 or better. Conclusion Endophthalmitis caused by nontuberculous mycobacterium often included chronic recurrent or persistent intraocular inflammation and frequently required removal of ocular device (intraocular lens, glaucoma implant, or scleral buckle). The majority of the isolates were susceptible to amikacin and clarithromycin. Visual outcomes in these patients even after treatment were generally poor.