Propionibacterium acnes as a cause of visually significant corneal ulcers

Purpose. To report Propionibacterium acnes as a cause of vision-threatening infectious keratitis and to discuss culture isolation and antibiotic treat ment. Methods. Retrospective case series presentation collected from three academic medical centers. Results. Six cases of P. acnes infectious keratit is are presented, all of which were associated with a compromised corneal b arrier or environment. All cases were culture-positive on thioglycolate bro th; none became positive before 7 days of growth. No other organisms were i solated from any culture, and the growth of P. acnes occurred in some cases despite negative gram stains. Conclusion. P. acnes can produce vision-debi litating keratitis when the cornea is compromised. Growth in culture should be monitored for at least 10 days to ensure isolation of this fastidious o rganism. P. acnes may respond to several different antibiotics that have gr am-positive coverage, but it should be treated with vancomycin to enhance c learance of the organism.