Microbiology of the conjunctival sac before and after cataract surgery

Abstract

Background: The aim of the study was to evaluate the bacterial flora and antibiotic susceptibility profile of bacterial isolates taken from the conjunctival sacs of patients undergoing phacoemulsification cataract surgery, and to compare them. Material and methods: In total, 200 conjunctival swabs were collected from 50 patients between June and December of 2017. Results: The most common pathogen collected from the conjunctival sacs before surgery was coagulase-negative staphylococci (CoNS) (65% of swabs); 45 of them (45%) were methicillin-sensitive staphylococci (MS-CoNS) and 25 (25%) were methicillin-resistant staphylococcus (MR-CoNS). Following the surgeries, CoNS were collected from 34 swabs (34%), 16% of which were taken from the eye on which the operation had been performed. Twenty-three swabs (23%) were MS-CoNS and 11 (11%) were MR-CoNS. The number of CoNS-positive swabs after pharmacotherapy decreased by 52%. The possibility of obtaining sterile swabs was statistically and significantly higher in eyes in which chemoprophylaxis was used [(OR = 4.58, 95% CI: 2.91–7.21), p < 0.001)]. The possibility of obtaining sterile swabs was not correlated with gender (p = 0.866) or diabetes (p = 0.712), but was observed more frequently in younger patients (p = 0.001). Multi-drug resistant bacteria were detected in 34 swabs before surgery (34%) and in 26 samples after operations (26%). Conclusions: It is probably impossible to sterilise the conjunctival sac. There is a risk of multi-drug resistant bacterial flora colonising the conjunctival sac.