Evaluation of activity of selected ophthalmic antimicrobial agents in combination against common ocular microorganisms

Abstract

Objective - To determine in vitro efficacy of gentamicin, tobramycin, and miconazole when used in combination, with or without atropine, against Pseudomonas or Aspergillus sp. Procedure - Selected ophthalmic agents were combined for predetermined times. Sterile disks impregnated with the combined solutions were prepared and placed on Mueller-Hinton plates that were seeded with Pseudomonas or Aspergillus sp. Zones of growth inhibition were measured at postincubation hours 24 and 48. Results - Tobramycin alone inhibited growth of Pseudomonas sp, whereas miconazole inhibited growth of Aspergillus sp. Significant differences in zones of growth inhibition when atropine was combined with tobramycin, when gentamicin was combined with miconazole, or when atropine was combined with miconazole and gentamicin, were not detected. Clinical Relevance - Combining selected ophthalmic therapeutic agents for as long as 6 hours does not appear to alter the in vitro efficacy of the agents against microorganisms used in this study.