Culture positivity and distribution of the conjunctival sac bacteria in the perioperative period of corneal refractive surgery.

ABSTRACT

The objective of this study was to investigate the culture positivity and distribution of the conjunctival sac bacteria in the perioperative period of corneal refractive surgery. The selected time points of the perioperative period included before the use of antibiotic eye drops, before eye wash (after the use of antibiotic eye drops), after eye wash, and immediately after surgery. Conjunctival specimens obtained at the four time points were cultured to detect the positivity and distribution of bacteria. Before prophylactic antibiotic eye drops were administered, 49 eyes (50%) had positive bacterial culture results, with 45 isolates (91.8%) identified as Staphylococcus epidermidis. The culture positivity rates of the conjunctival sac specimens before eye wash, after eye wash, and immediately after surgery were 19.4%, 3.1%, and 4.1%, respectively. The difference was significant before and after the use of antibiotics and before and after eye wash (both P < 0.001). Staphylococcus epidermidis was the major pathogen in the conjunctival sac before corneal refractive surgery, and the culture positivity rate of the conjunctival bacteria was higher in males. Sixteen of 37 eyes (43.2%) with contact lenses had positive culture results, compared to 33 of 61 eyes (54.1%) without contact lenses (P > 0.05). The judicious preoperative use of antibiotic eye drops combined with the surgical sterile eye wash procedure maximised the removal of conjunctival sac bacteria. Skilled surgical manipulations generally did not increase the risk of infection.