Abstract
Purpose: :
To determine the efficacy of topical gatifloxacin in eliminating conjunctival bacterial flora following a three-day application in patients undergoing intravitreal injection.
Methods: :
Prospective, masked randomized evaluation of 298 eyes in 149 patients scheduled to undergo intravitreal injection. Patients were randomly assigned to study and control groups and study group participants were instructed to instill 1 drop of topical gatifloxacin QID in their injection eye for three days prior to their next scheduled intravitreal injection with control subjects using no antibiotic treatment. Cultures were taken from the bulbar conjunctiva at the injection site 3 mm posterior to the limbus (C2) and from the mirrored anatomic site on the contralateral eye (C1) on the day of the patients scheduled injection. All patients then received dilation drops and those assigned to the study group received an additional drop of gatifloxacin in their injection eye. Following the use of topical povidone iodine (PVI) and immediately prior to their injection, an additional culture was collected from the injection site (C3). Finally, the injection needle was collected and cultured (C4). Culture swabs were inoculated onto SeptiChek culture broth and incubated at 37°C for 5 days. Positive cultures were then gram stained for identification purposes. The individuals obtaining the cultures and analyzing the results were masked with regard to group assignment.
Results: :
The percentage of positive cultures following three days of topical gatifloxacin was 24% compared to 52% in untreated controls (p=.001). PVI alone produced a drastic reduction in the percentage of positive cultures from 52% to 4% (p<.001). Similarly PVI and 1 drop of gatifloxacin produced a further reduction from 24% to 10% (p=.033) in pretreated study eyes. Although these pretreated eyes had a smaller bacterial load than their contralateral control eyes, 24% versus 42% (p=.027), and received another drop of topical antibiotic prior to injection, there was no statistical difference in the rate of positive cultures between control and study participants following the use of PVI, 4% versus 10% (p=.215). Needle cultures were not statistically different between control and study groups with 0% versus 3% (p=.498), respectively.
Conclusions: :
A 3-day application of topical gatifloxacin appears to be effective at reducing the injection site bacterial load over no pretreatment. This regimen, however, conferred no increased bactericidal benefit when compared to a standard PVI preparation prior to injection.
Clinical Trial: :
www.clinicaltrials.gov NCT00410891
Keywords: injection • endophthalmitis • age-related macular degeneration