The aim of this study was to investigate the etiological spectrum of infectious endophthalmitis and analyze the drug susceptibility characteristics of etiological organism in Shandong Province.

A total of 350 patients (350 eyes) were collected from Eye Hospital of Shandong First Medical University (Shandong Eye Hospital) from 2013 to 2020 who were clinically diagnosed with suspected infectious endophthalmitis and received aqueous fluid and (or) vitreous samples for smear test, bacterial culture and fungal culture before examination and retrospectively analyzed. Isolated bacteria and candida were identified and drug sensitive test by Vitek 2 Compact automatic microbiological analysis system. The drug sensitivity data were analyzed by WHONET5.6 and expressed as cases and percentage.

Among 350 cases of suspected infectious endophthalmitis, there were 317 cases with exogenous endophthalmitis and 33 cases with endogenous endophthalmitis, accounting for 90.6% and 9.4%, respectively. There were 269 cases with both aqueous humor and vitreous fluid collected, 81 cases with aqueous humor collected. There were 67 cases with Gram-positive cocci, 8 cases with gram-negative bacteria, 8 cases with Gram-positive bacilli and 16 cases with fungi detected by smear, accounting for 28.3%, 67.7%, 8.1%, 8.1% and 16.1%, respectively. For culture in vitro, 135 cases were positive, a positive rate of 38.6%. There were 144 strains of isolated pathogenic organism, including 87 cases with Gram-positive cocci, 12 cases with Gram-positive bacilli, 15 cases with Gram-negative bacilli, and 30 cases with fungi, accounting for 60.4%, 8.3%, 10.5% and 20.8%, respectively. According to intraocular fluid smear and (or) culture positive as the gold standard for the diagnosis of infectious endophthalmitis, there were 211 patients of them with positive intraocular fluid smear and (or) in vitro culture, who were finally diagnosed as infectious endophthalmitis, an positive rate of 60.3%. Among of pathogens, Staphylococcus with negative coagulase was the top1, followed by Streptococcus. The main fungi were Fusarium and Aspergillus. The sensitivity of the isolated strains to levofloxacin ranged from 39.3% to 84.6%, which was higher than that of other drugs.

From 2013 to 2020, the ocular trauma was the main pathogenic factor of infectious endophthalmitis in Shandong. Gram-positive coccus, especially Staphylococcus with negative coagulase, were the main pathogenic bacteria of infectious endophthalmitis.