Postoperative contamination after using vancomycin and gentamicin during phacoemulsification
J. F. Ferro, M. de-Pablos, M. J. Logrono, L. Guisasola and F. Aizpuru
Department of Ophthalmology, Hospital of Txagorritxu, Vitoria, Spain. jferro@redestb.es
OBJECTIVE: To investigate if the addition of vancomycin and gentamicin to
the irrigating solutions during phacoemulsification with lens implantation
reduces the incidence of positive postoperative intraocular cultures.
DESIGN: Two-part double-masked, placebo-controlled, randomized clinical
trial. PATIENTS: In the preliminary study, intracameral antibiotic
concentrations were measured immediately after surgery (in 10 eyes) and 2
hours after surgery (in 10 eyes) in patients treated with antibiotics. In
the primary study, 120 eyes underwent uncomplicated surgery. The treatment
group and the placebo group were composed of 60 eyes each. INTERVENTION:
The treatment group received vancomycin, 20 micrograms/mL, and gentamicin,
8 micrograms/mL, in the irrigating fluid. The placebo group received only
irrigating fluid. All patients in the primary study underwent anterior
chamber aspiration following surgery, and culturing was performed 2 hours
later. MAIN OUTCOME MEASURE: Identification and quantification of positive
cultures in thioglycolate broth and chocolate agar. RESULTS: In the
preliminary study, the half-life of both intraocular antibiotics was less
than 2 hours. In the primary study, intraocular aspirates yielded positive
cultures in 3 specimens (5.0%) in the antibiotic-treated group and in 7
specimens (12.0%) in the placebo group. CONCLUSIONS: Although we found a
higher rate of positive postoperative cultures in the placebo group (odds
ratio = 2.51), 2 hours of contact between the antibiotic solution and
bacteria did not produce results that reached statistical significance (P
=.18) to support adding vancomycin and gentamicin to the irrigating
solutions during phacoemulsification. Further studies are needed to
evaluate the clinical implications of using antibiotics in irrigating
solutions.
