Ocular bacterial infections at a tertiary eye center in China: a 5-year review of pathogen distribution and antibiotic sensitivity

Abstract

AIM: To provide statistical evidence for the use of antibiotics in ophthalmology by assessing the distribution and antibiotic sensitivity of bacterial isolates from ocular specimens with suspected microbial infections. METHODS: This study applied a retrospective analysis of 3690 bacterial isolates from ocular specimens, which were obtained from the conjunctiva, cornea, aqueous humor, vitreous body, and other ocular sites of the patients at Shandong Eye Institute in northern China from January 2013 to December 2017. The parameters assessed mainly included the distribution of isolated bacteria and the results of susceptibility tests for antibiotics. In the analysis of antibiotic sensitivities, the bacteria were divided into four groups according to gram staining, and statistical methods were used to compare their antibiotic sensitivities. RESULTS: Among the 3690 isolated bacterial strains, Staphylococcus epidermidis (2007, 54.39%) accounted for the highest proportion. As for the total isolates, their sensitivity rate to gatifloxacin was up to 90.01%, with four types of gram-stained bacteria being all highly sensitive to it, but their sensitivity rate to levofloxacin was only 51.91%. The sensitivity rate of gram-negative bacilli (G-B) to levofloxacin was 83.66%, significantly higher than the other three types of gram-stained bacteria (P<0.05). Gram-positive cocci (G+C, 97.95%) and gram-positive bacilli (G+B, 97.54%) were more sensitive to vancomycin than gram-negative cocci (G-C, 70.59%) and G-B (68.57%; P<0.05). For fusidic acid, the sensitivity rates of G+C (89.83%) and G+B (73.37%) were significantly higher than that of G-B (29.83%; P<0.05). The gram-negative bacteria’s sensitivity rate to cefuroxime was as low as 59.25%, but only G-B was less sensitive to cefuroxime (57.28%), while G-C was still highly sensitive (89.29%). The sensitivity rate of gram-positive bacteria to moxifloxacin was as high as 80.28%, but only G+C was highly sensitive to moxifloxacin (81.21%), while G+B was still less sensitive (32.00%). CONCLUSION: Staphylococcus epidermidis is the predominant isolate in all ocular specimens with bacteria. Gatifloxacin is more suitable for topical prophylactic use than levofloxacin in ophthalmology when necessary. Vancomycin and fusidic acid both have better effects on gram-positive bacteria than gram-negative bacteria. More accurate antibiotic sensitivity analysis results can be obtained when a more detailed bacterial classification and more appropriate statistical methods are performed.

Keywords

• bacteria
• ocular infections
• pathogen
• antibiotic sensitivity