To describe causative pathogens involved in microbial endophthalmitis and trends of microbial isolates sensitivity and resistance to routinely used ophthalmic antibiotics.

This is a retrospective study on smear and culture samples of aqueous and vitreous humor in patients who came to Farabi eye hospital emergency ward from January 2012 to December 2018.

2999 samples were collected from intraocular origin during 6 years (1231 samples from aqueous humor and 1768 samples from vitreous humor). Mean age of patients were 59.17±21.30. 75% were culture negative and S.epidermidis (6%) and S.pneumonia (4%) were the most prevalent microbial isolates. In endophthalmitis patients, younger than 19 years, 69.3% were culture negative. S.viridans ,S.pneumonia and S.aureus accounted for 13% ,7.3% and 2.6% respectively. In 19-50 year old patients , 78.7% were culture negative , and S.epidermidis (9.1%) and S.viridans (3.7%) were the most prevalent microorganisms. In patients older than 50 years of age, 76.4% were culture negative and S.epidermidis (6.6%) and S.pneumonia (4.4%) were the most common isolates. In our study resistance of S.pneumonia to ceftazidim siginificantly increased after 2014 however other changes in antibiotic susceptibility profile was not significant.

In our study 75% of culture samples of intraocular fluid of patients with intraocular infection were negative and S.epidermidis and S.pneumonia were the most common isolates (6% and 4% respectively). In patients younger than 19 S.viridans and in older than 19 S.epidermidus were the most prevalent microorganism detected in cultures.