Background: The conjunctival flora is of great interest for each case of intraocular operation preventing postoperative infections. Despite of negative cultures before the operation we investigated in a prospective randomized study perioperatively the bacterial situation of the conjunctiva in 105 patients.
Material and methods: We took conjunctival swabs for microbiological examination from patient's eye operated on cataract or glaucoma, on the day of admission to the eye clinic and in the morning of the operating day. In addition, specimens were taken by nurses with Transwab MW-172 P before the local anaesthesia, disinfection of the conjunctiva and lids and application of eye drops, after these procedures by a research worker, at the end of the operation by the surgeon and two to three days after the operation by nurses with Transwab MW-172 P again. In 53 patients we collected lacrimal fluid to measure the lysozyme concentration.
Results: Out of 686 conjunctival swabs we have found 126 (18.4%) positive cultures. Staphylococcus epidermidis had the highest incidence (109 = 86.5%) followed by Staphylococcus aureus (7 = 5.5%). Only in 28 eyes all conjunctival swabs, taken at different times, were negative. There was an increase of positive cultures from routine swabs on the day of admission from 13 (12.4%), to 33 (31.7%) in the swabs taken on the day of the operation in the morning. On the other side the positive cultures decreased then continuously before and after the preparation of the operation, at the end of the operation and during two to three days postoperatively. There was'nt any statistical correlation between the concentration of the lacrimal lysozyme and the rate of positive cultures.
Conclusion: The preoperative bacteriological diagnostic of the conjunctiva is important mainly for the prevention of postoperative endophthalmitis despite the transience and fluctuation of the conjunctival flora but also in case of endophthalmitis for rapid specific antibiotical therapy.