Microbiological cure times in acanthamoeba keratitis

Abstract

Aims The purpose of this study was to estimate the duration of treatment necessary for sequential acanthamoeba laboratory tests from corneal scrapings to become negative, and to assess predictors that affect this duration period. Methods We included all patients with at least one positive acanthamoeba culture or Giemsa stain at the F.I. Proctor Foundation Microbiology Laboratory from 1996 to 2009. A parametric survival analysis was performed among patients with repeat cultures to assess significant predictors for extended clearance time. Simulations were performed to estimate clearance time in the entire patient population, assuming imperfect sensitivity. Results Thirty-seven patients with laboratory evidence of acanthamoeba had testing at 69 time points. The median clearance time among eyes with repeat cultures was 42.5 days (interquartile range (IQR) 22.0-82.0 days; unadjusted parametric model). Initial visual acuity was the only predictor significantly associated with clearance time in univariate analyses (Po0.0001). Using initial visual acuity as a predictor for clearance time among the entire patient population, the estimated clearance time decreased to 38.7 days (95% confidence interval (CI) 27.9-53.5 days). When the imperfect sensitivity of the culture technique was also taken into account, the estimated clearance time was 44.1 days (95% CI 31.9-61.0 days). Conclusion The duration of infection with acanthamoeba keratitis undergoing treatment has not been well characterized. In this report we estimate a median clearance time of approximately 6 weeks, with an IQR of 22-82 days.

A One-Step Multiplex PCR forAcanthamoebaKeratitis Diagnosis and Quality Samples Control

“…27 Similar to culture, PCR follow-up of corneal scraping could be tested to evaluate the clearance of the pathogen, even if detection of Acanthamoeba DNA could occur in the presence of dead microorganisms. Other AK diagnostic complementary tools, such as in vivo confocal microscopy, [28][29][30] could also be used to monitor treatment response, but this remains to be evaluated.…”

Riboflavin and ultraviolet A as adjuvant treatment against Acanthamoeba cysts

“…Recently, in an online survey of worldwide ophthalmologists, Oldenburg et al found that PHMB and chlorhexidine were the most common choices as monotherapy for treating AK . Although the majority of patients achieve clinical cure, the duration of treatment for AK can be very long . and despite all the currently available drugs, many patients develop severe corneal scarring or even perforation…”

“…26 Although the majority of patients achieve clinical cure, the duration of treatment for AK can be very long. 27 and despite all the currently available drugs, many patients develop severe corneal scarring or even perforation. 28 The knowledge that ultraviolet radiation can be used to activate riboflavin and reduce pathogens in vitro and ex vivo such as in platelet concentrates, 12 together with the popularization of the CXL technique in which UVA is irradiated for 30 min at 3 mW/cm 2 (5.4 J) over a cornea treated with topical riboflavin, 29 led to the idea that the same parameters used for CXL could be used for reducing pathogens.…”

Acute keratoconjunctivitis due to contamination of contact lens care solution with histamine-producing Raoultella species

“…[ 1 ] Treatment duration is generally lasting months. [ 2 ] Corneal hypoxia is a noninflammatory corneal complication caused by the extended contact lens wear and is characterized by corneal edema, infiltrative keratitis, and neovascularization. [ 3 ] It has been reported to recover several hours after removing contact lens.…”