Antibiotic susceptibility of preoperative normal conjunctival bacteria.

Abstract

To determine the antibiotic susceptibility of preoperative conjunctival bacterial flora. In vitro study. Antibiotic susceptibility of conjunctival bacterial strains isolated from 164 patients undergoing intraocular surgery was determined using the Kirby-Bauer disk-diffusion technique. Among the 162 bacteria isolated, 124 (76%) were coagulase-negative staphylococci (CNS), with 2% resistant to gatifloxacin and moxifloxacin, and none were resistant to vancomycin or minocycline. Other bacteria isolated were 19 Staphylococcus aureus (S. aureus), 8 Streptococcus Group D, and 11 gram-negative rods. Most S. aureus (>85%) were susceptible to all antibiotics except for the penicillin and macrolide groups. No streptococci were resistant to gatifloxacin, levofloxacin, moxifloxacin, mezlocillin, imipenem, or vancomycin. None of the gram-negative rods were resistant to the fluoroquinolones. Approximately one half of all bacteria were resistant to erythromycin. One in three patients harbored multi-resistant bacteria (resistant to > or = five antibiotics). Newer-generation fluoroquinolones provide excellent broad-spectrum coverage against conjunctival bacterial flora.