Relationship of In Vitro Susceptibility to Moxifloxacin and In Vivo Clinical Outcome in Bacterial Keratitis

Abstract

NCT00324168.

Moxifloxacin Susceptibility Mediates the Relationship between Causative Organism and Clinical Outcome in Bacterial Keratitis

“…[2][3][4][5][6][7] Susceptibility has also been shown to correlate with the causative organism in these infections. 4,6 It is commonly thought that clinical outcomes differ by causative organisms in systemic and ocular infections. For example, in bacterial keratitis, infection with Pseudomonas aeruginosa has been suggested to be associated with poor outcome.…”

“…In a recent large clinical trial, the Steroids for Corneal Ulcers Trial (SCUT), clinical outcomes were associated with antibiotic susceptibility. 6 Here, we assess the relationship between organisms and clinical outcome and the portion of the effect that the organism has on outcome that can be attributed to differences in susceptibility to moxifloxacin as measured by the minimum inhibitory concentration (MIC) in SCUT.…”

“…Previously, we showed that MIC was predictive of 3-week visual acuity and correlated with causative organisms, and thus we were able to do a mediation analysis. 6 Mediation analysis estimated that approximately 13% (95% CI, 3%-24%, P ¼ 0.015) of the effect of organisms on 3-week visual acuity was indirect via MIC. Controlling for randomized treatment arm, we found that this effect was 12.8% (P ¼ 0.018).…”

“…Previously, SCUT showed that a higher MIC was predictive of a worse 3-week visual acuity, although the effect size was relatively small. 6 In addition, MICs varied significantly in different organisms, with the highest MIC 50 of moxifloxacin found with P. aeruginosa. 6 In this analysis, we attempted to further elucidate the relationship of the organism, MIC, and clinical outcome.…”

“…6,9 In brief, corneal scrapings for smear and culture were obtained at the presentation visit after slit lamp examination. Two scrapings were smeared on Gram stain and potassium hydroxide (KOH) wet mount.…”