Abstract
Purpose:
The administration of short courses of topical antibiotic drops before and/or after intravitreal injections is a common practice, but increasing evidence suggests this may not lower the risk of infectious endophthalmitis and could increase rates of antimicrobial resistance. The purpose of the present study is to determine the antimicrobial resistance profiles in patients who have received numerous (≥ 20) courses of antibiotics for intravitreal injection compared with untreated controls.
Methods:
This study compared 10 control patients without prior intravitreal injection to 12 patients who had undergone ≥ 20 prior intravitreal injections accompanied by a course of topical antibiotics for two days before and/or after the injection procedure. The inferior conjunctival fornix and ipsilateral nasopharynx were cultured and evaluated via disk diffusion method for sensitivity to the following antibiotics: amoxicillin/ clavulanate, cefazolin, cefoxitin, erythromycin, moxifloxacin, trimethoprim/ sulfamethoxazole, linezolid, clindamycin, and doxycycline.
Results:
The mean age (±standard deviation) was similar between control and treated groups: 73.6 (±10.1) and 84.7 (±7.2), p=NS. The number [range] of ocular isolates obtained from the control and treated groups was, respectively, 1.9 [0-4] and 1.0 [0-2], p=.025. The two most commonly isolated bacteria in the treated group were: S. epidermidis and S. lugdunesis; those in the control group were: S. epidermidis and S. aureus. The rates of antimicrobial resistance were 33% in the control group and 80% in the treated group, p=.046.
Conclusions:
Repeated short courses of antibiotics for intravitreal injection did decrease the number of isolates cultured from the conjunctival fornix compared with controls. The rates of antibiotic resistance were higher in the antibiotic treated group compared with controls. Physicians must balance the benefit of reducing the number of surface isolates with the heightened risk of increasing antimicrobial resistance in deciding whether topical antibiotics are appropriate prophylaxis for intravitreal injections.
Keywords: 422 antibiotics/antifungals/antiparasitics •
513 endophthalmitis •
462 clinical (human) or epidemiologic studies: outcomes/complications