Topical antibiotic prophylaxis before intravitreal injections: a pilot study

PurposeTo explore whether topical antibiotic prophylaxis in patients scheduled for intravitreal injections achieves surface sterility in a greater proportion of subjects as compared to povidone-iodine alone.Material and methodsA randomized, triple-blind clinical trial. Population: patients scheduled for intravitreal injections for maculopathy. Inclusion criteria: any sex and race, age 18 years and above. Subjects were randomized into 4 groups: the first group applied chloramphenicol (CHLORAM), the second netilmicin (NETILM), the third a commercial ozonized antiseptic solution (OZONE), and the fourth applied no drops (CONTROL). Outcome variable: percentage of non-sterile conjunctival swabs. Specimens were collected before and after the application of 5% povidone-iodine moments before the injection.ResultsNinety-eight subjects (33.7% females, 64.3% males), mean age: 70.2 +/- 9.3 years (54-91). Before povidone-iodine, both the CHLORAM and NETILM group showed a lower percentage of non-sterile swabs (61.1% and 31.3% respectively), as compared to the OZONE (83.3%) and CONTROL (86.5%) groups (p < .04). However, this statistical difference was lost after the application of povidone-iodine for 3 min. Percentage of non-sterile swabs in each group after applying 5% povidone-iodine: CHLORAM 11.1%, NETILM 12.5%, CONTROL 15.4%, OZONE 25.0%. This was not statistically significant (p > .05).ConclusionsTopical antibiotic prophylaxis with chloramphenicol or netilmicin drops decreases the bacterial load on the conjunctiva. However, after the application of povidone-iodine, all groups showed a significant reduction in the percentage of non-sterile swabs, and this value was comparable among all groups. For this reason, authors conclude that povidone-iodine alone is sufficient and prior topical antibiotic prophylaxis is not indicated.

Automated summary

This study aimed to investigate whether topical antibiotic prophylaxis in patients scheduled for intravitreal injections achieves surface sterility in a greater proportion of subjects compared to povidone-iodine alone. The results showed that both chloramphenicol and netilmicin drops reduced the bacterial load on the conjunctiva, but after the application of povidone-iodine, there was a significant reduction in non-sterile swabs in all groups, and this reduction was comparable among all groups. Therefore, the authors concluded that povidone-iodine alone is sufficient and prior topical antibiotic prophylaxis is not indicated.