Shorstein NH, et al. Am J Ophthalmol. 2021;doi:10.1016/j.ajo.2021.02.007.
Optimal dose, concentration of moxifloxacin needed to prevent endophthalmitis
Endophthalmitis cases in a large retrospective clinical cohort study of patients who underwent cataract surgery were related to organism resistance in cefuroxime-treated eyes and sensitive organisms in moxifloxacin-treated eyes.
“The main take-home message from the study is to inject enough moxifloxacin to kill sensitive bacteria, either by injecting 0.5 mL of moxifloxacin 0.1%, our preferred method, or by injecting 0.1 mL of moxifloxacin 0.5%,” study co-author Neal H. Shorstein, MD, told Healio/OSN.
The study included 216,141 noncomplex phacoemulsification cataract surgery cases at Kaiser Permanente Northern California from 2014 to 2019. Researchers evaluated acute postoperative endophthalmitis rates within 90 days of the surgery, including culture and antibiogram results, intracameral and topical antibiotic agent, and dose.
Researchers also examined preoperative anterior chamber depth and postoperative anterior chamber volume in a post hoc analysis.
Out of 216,141 surgeries, 34 cases of endophthalmitis were observed. Eyes injected with moxifloxacin experienced an infection rate of 0.02% compared with 0.013% of cefuroxime-injected eyes. Of the endophthalmitis cases, 13 were injected with cefuroxime, 19 with 0.1 mL of moxifloxacin 0.1%, one with 0.5 mL of moxifloxacin 0.1% and one with 1 mL moxifloxacin 0.1%. In 14 of the 33 cases that were tested, an organism was identified.
In the five eyes injected with cefuroxime that were culture positive, four were cefuroxime resistant, and in one case, sensitivity was not recorded. In eight cases injected with 0.1 mL moxifloxacin, six cases were found to be sensitive to the drug, one case was resistant, and one case had no sensitivity information. Researchers found one eye injected with 1 mL moxifloxacin resulted in a Streptococcus infection that was sensitive to the drug, the study said.
Moxifloxacin eyes had a statistically significant greater mean preoperative anterior chamber depth compared with cefuroxime eyes (P = .03). There was a higher mean pseudophakic anterior chamber volume in moxifloxacin eyes compared with cefuroxime eyes, but the difference was not significant.
“The tendency toward a larger reservoir for drug in the moxifloxacin eyes may have resulted in too low of a concentration of drug to achieve sufficient bactericidal activity,” the study authors wrote.