# Staphylococcus cohnii Causing a Latent Endophthalmitis: A Case Report

## TL;DR

A 72-year-old woman developed a delayed eye infection caused by Staphylococcus cohnii after cataract surgery, requiring multiple treatments and lens removal.

## Contribution

This case report highlights Staphylococcus cohnii as a rare but important cause of latent postoperative endophthalmitis.

## Key findings

- Staphylococcus cohnii was identified as the causative agent in a case of delayed endophthalmitis.
- The infection was associated with biofilm formation, complicating treatment and leading to implant failure.
- Multiple surgical interventions were required to manage the persistent intraocular infection.

## Abstract

Objective: We report a case of latent postoperative endophthalmitis caused by Staphylococcus cohnii in a 72-year-old woman.

Observation: The patient was referred to the department of ophthalmology with blurry vision in her right eye 12 days after phacoemulsification. The clinical examination showed signs of endophthalmitis. A vitreous tap, with intraocular injection of ceftazidime, was performed, and topical dexamethasone and tobramycin were initiated. The postoperative follow-up showed reduction in the intraocular reaction, and the patient was afterwards discharged. After 6 months, her private ophthalmologist referred the patient again with signs of uveitis and macular edema. The clinical examination showed hypopyon and infiltrates on the posterior lens capsule which led to a vitrectomy with the removal of the posterior lens capsule infiltrate. With no signs of improvement at the postoperative follow-up, the intraocular lens was removed.

Results: A pathological examination with H&E, Gram, and Periodic Acid Schiff showed gram-positive cocci in relation to the lens capsule. Polymerase chain reaction was performed, detecting DNA of Staphylococcus cohnii.

Conclusion and Importance:
Staphylococcus cohnii should be considered in cases of latent endophthalmitis. Staphylococcus cohnii is a gram-positive coagulase-negative bacterium that produces biofilm. Biofilm can promote adherence to implants leading to failure of therapy.