Endogenous endophthalmitis: the organism shapes the course, and Serratia costs eyes

Design

Retrospective multicentre cohort

Population

305 eyes (261 patients) with culture-positive endogenous endophthalmitis at 9 US centres

Primary outcome

Final visual acuity, retinal detachment and enucleation by organism

Effect

Blood culture positive 66.2% vs vitreous 31.1%; enucleation 27.7% with gram-negative organisms

This retrospective study pooled 305 eyes (261 patients) with culture-positive endogenous endophthalmitis at nine US academic centres from 2012 to 2024.

Staphylococcus aureus caused 37.7%, fungi 19.3%, gram-negative bacteria 15.4% and streptococci 13.4%. Blood cultures were positive in 66.2% of eyes, vitreous in 31.1% and aqueous in 8.9%; blood and eye organisms matched in only 62% of paired cases. Fungal cases were linked to immunosuppression and intravenous drug use, gram-negative cases to urinary sources. Fungal eyes presented with better acuity. Retinal detachment was commonest with S. aureus and streptococci. Enucleation was highest with gram-negative infection (27.7%), driven by Serratia (85.7%). Presenting acuity was the most consistent predictor of final vision.

For practice, blood cultures are the most productive single test, and the eye sample often grows nothing, so empirical cover must be broad. A gram-negative or Serratia result should prompt an early frank conversation about the risk to the globe. This is a retrospective culture-positive series, so it excludes culture-negative cases, which are common.

• Take blood cultures in every suspected endogenous endophthalmitis; they were positive in two-thirds of eyes.
• Give broad empirical intravitreal cover, as vitreous cultures grew an organism in only about one-third.
• Look for a urinary source when a gram-negative organism is suspected or grown.
• Counsel early about the high risk of globe loss with gram-negative, particularly Serratia, infection.

Why it matters

Eye cultures alone miss most organisms, and the organism predicts whether the eye can be saved.

Don't overread it

Retrospective and limited to culture-positive cases; outcomes by organism are associations, not treatment comparisons.

The statistics, in plain English

logMAR 1.3 to 2.1 corresponds roughly to counting fingers or worse; lower numbers are better vision. The Serratia enucleation rate (85.7%) is based on only a handful of cases, so it is a warning signal rather than a precise figure.

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