LATE DIAGNOSIS OF Cutibacterium acnes (FORMERLY Propionibacterium acnes ) ENDOPHTHALMITIS AND THE IMPORTANCE OF DUAL TESTING WITH BACTERIAL CULTURE AND POLYMERASE CHAIN REACTION.

Purpose: The purpose of this study was to describe two cases of Cutibacterium acnes endophthalmitis that reinforce the importance of performing both bacterial culture and 16S polymerase chain reaction when the causative pathogen is unclear or difficult to culture, such as C. acnes . A case of C. acnes endophthalmitis complicated by subbuckle scleral perforation is illustrated with intraoperative photography.

Methods: This is a two-case series.

Results: Case 1 describes a case of C. acnes endophthalmitis in a longstanding pseudophakic patient after multiple vitrectomies for recurrent retinal detachment, complicated by subbuckle scleral perforation. Bacterial culture revealed C. acnes while 16S PCR was negative. Conversely, Case 2 demonstrates a case of chronic endophthalmitis diagnosed one year after cataract surgery. PCR (with repeat tap for confirmation) revealed C. acnes with a negative culture.

Conclusion: When the causative pathogen of endophthalmitis is unclear, dual testing of microbial culture and C. acnes 16S PCR improves the diagnostic yield of investigations for fastidious pathogens. C. acnes can present as an indolent or virulent endophthalmitis.