Rothia dentocariosa isolated from a corneal ulcer

Rothia dentocariosa is a common commensal in the oropharyngeal cavity but a rare human pathogen. Ocular culture has been documented only twice previously, both from vitreous samples taken in the context of endophthalmitis. These cases, and other reports of human Rothia infection, have proposed hematogenous spread from the oropharynx as the mode of transmission.

A case report of an 11-year-old boy with a progressive right corneal abscess that required penetrating keratoplasty because of corneal perforation is detailed. The keratitis recurred in the graft, leading to an almost total epithelial defect, hypopyon, and descemetocele within 3 months.

R. dentocariosa was eventually isolated from the cornea, and the patient made a rapid recovery once topical medication was altered accordingly. Microbial identification was confirmed at a reference laboratory by using partial sequencing of 16s rDNA. The father later described his son's habit of wetting the fingertip with saliva before eyelid rubbing as a means of reducing ocular discomfort.

This is the first reported case of corneal isolation of R. dentocariosa. It also suggests a direct mode of transmission of the organism to the eye by contaminated saliva.