What are the causes of Endophthalmitis (inflammation of the internal contents of the eye)?

From the Guidelines

Endophthalmitis is primarily caused by bacterial or fungal infections that enter the eye's interior chambers, with the most common causes being bacterial contamination during or after eye surgery, particularly cataract surgery, and trauma to the eye. The most common bacterial causes include Staphylococcus epidermidis and Staphylococcus aureus, while fungal pathogens like Candida and Aspergillus species can also cause endophthalmitis, especially in drug users or those with compromised immune systems 1. Some key points to consider include:

• Post-operative endophthalmitis is most often caused by gram-positive organisms, with coagulase-negative staphylococci predominating 1
• Endogenous endophthalmitis is usually caused by organisms most responsible for bloodstream infections, such as Candida albicans and related species, Aspergillus spp, S. aureus, and S. pneumoniae 1
• Delayed or improper treatment of eye injuries, contaminated medications or instruments used during eye procedures, and intraocular foreign bodies can also lead to this serious eye infection 1
• The inflammation occurs because these pathogens trigger an immune response within the eye's confined space, potentially leading to vision loss if not treated promptly with appropriate antibiotics or antifungal medications 1 It's worth noting that the evidence from 1 suggests that Candida endophthalmitis with vitritis must be managed with close cooperation between ophthalmologists and infectious diseases specialists, and that early pars plana vitrectomy can be beneficial in reducing the risk of retinal detachment and improving outcomes. However, the most recent and highest quality study 1 prioritizes the management of Candida endophthalmitis with vitritis, and recommends intravitreal injection of antifungal agents and consideration of pars plana vitrectomy to achieve high drug concentrations in the posterior chamber and remove the vitreous. Overall, the management of endophthalmitis requires prompt and appropriate treatment to prevent vision loss and other complications.

From the Research

Causes of Endophthalmitis

• Endophthalmitis is a serious ophthalmologic condition involving purulent inflammation of the intraocular spaces, typically caused by bacterial or fungal infections 2, 3, 4, 5, 6
• The mechanism of entry into the eye can be either exogenous, involving seeding of an infectious source from outside the eye (e.g., trauma or surgical complications), or endogenous, involving transit of an infectious source to the eye via the bloodstream 2, 3, 4, 5, 6
• Exogenous endophthalmitis is more common than endogenous endophthalmitis, with post-operative endophthalmitis being the most frequently encountered, particularly after cataract surgery 4, 5, 6
• Endogenous endophthalmitis is caused by the hematogenous spread of organisms from a remote infectious site to the eye, accounting for 2-15% of all cases of endophthalmitis 4

Common Causative Organisms

• The most common organisms causing endophthalmitis include:
  • Bacteria: coagulase-negative staphylococci, Staphylococcus aureus, streptococci, and Bacillus cereus 4, 5, 6
  • Fungi: Candida albicans, Aspergillus niger, and Fusarium solani 2, 3, 5
• The most common pathogens vary by category, with coagulase-negative staphylococci being the most common cause of post-cataract endophthalmitis, and Candida species being the most common cause of endogenous fungal endophthalmitis 5