MYCOBACTERIUM MANITOBENSE MASQUERADING AS CORYNEBACTERIUM PSEUDODIPHTHERITICUM IN A CASE OF POSTCATARACT SURGERY ENDOPHTHALMITIS.

Objective: To describe a case of postoperative Mycobacterium manitobense endophthalmitis with good visual outcome that is the first report of endophthalmitis by this organism.

Methods: Clinical and microbiological description of a patient with postoperative endophthalmitis.

Results: A 50-year-old chronic alcoholic man was referred to us with decreased vision in his right eye for 4 days. He had undergone cataract surgery with intraocular lens implantation in his right eye a month ago. The presenting vision in his right eye was counting fingers close to face. He was diagnosed as a case of postoperative endophthalmitis. Subsequently, the patient underwent pars plana vitrectomy and vitreous biopsy. The microbiologic investigation of the vitreous biopsy showed poorly stained gram-positive beaded bacilli that were acid fast, and growth in culture was identified as Corynebacterium pseudodiphtheriticum by Vitek 2 bacterial identification system. However, DNA analysis confirmed the organism to be M. manitobense. The patient responded well to repeat interventions with intravitreal antibiotics with a final reported visual acuity of 20/30 at 4 months after first intervention.

Conclusions: Although known to be an organism causing soft-tissue infections, M. manitobense can also cause postsurgical endophthalmitis. The diagnosis can be confused with Corynebacterium sp. on smear and culture. Subsequent DNA sequencing of the culture provides definite identification of the organism.