Risk factors for fluoroquinolone resistance in ocular cultures

To identify the risk factors associated with fluoroquinolone resistance in patients undergoing cataract surgery.

A total of 1,125 patients (1,125 eyes) who underwent cataract surgery at Veterans Health Service Medical Center from May 2011 to July 2012 were enrolled in this study. Conjunctival cultures were obtained from the patients on the day of surgery before instillation of any ophthalmic solutions. The medical records of patients with positive coagulase negative staphylococcus (CNS) and Staphylococcus aureus (S. aureus) cultures were reviewed to determine factors associated with fluoroquinolone resistance.

Of 734 CNS and S. aureus cultures, 175 (23.8%) were resistant to ciprofloxacin, levofloxacin, gatifloxacin, or moxifloxacin. Use of fluoroquinolone within 3 months and within 1 year before surgery, topical antibiotic use other than fluoroquinolone, systemic antibiotic use, recent hospitalization, ocular surgery, intravitreal injection and use of eyedrops containing benzalkonium chloride were significantly more frequent in resistant isolates than in susceptible isolates. In multivariable logistic regression analysis, ocular surgery (odds ratio [OR], 8.457), recent hospitalization (OR, 6.646) and use of fluoroquinolone within 3 months before surgery (OR, 4.918) were significant predictors of fluoroquinolone resistance, along with intravitreal injection (OR, 2.976), systemic antibiotic use (OR, 2.665), use of eyedrops containing benzalkonium chloride (OR, 2.323), use of fluoroquinolone within 1 year before surgery (OR, 1.943) and topical antibiotic use other than fluoroquinolone (OR, 1.673).

Recent topical fluoroquinolone use, hospitalization and ocular surgery were significantly associated with fluoroquinolone resistance in CNS and S. aureus isolates from ocular culture.