Abstract
Purpose: :
Disinfection of contact lenses is essential to healthy eye care, but the efficacy of this process is difficult to monitor. Microbial contamination has been monitored on surfaces and in fluids by intrinsic fluorescence [emitting light when excited by higher energy light] and has been used since the 1950s to monitor microbial metabolic state [viable cells, non-viable cells and spores]. This approach is sensitive [10 cells], requires no added reagents or sample contact, and measurements can be made in near real-time. The disinfection performance of AMO Easy RubTM contact lens solution on contact lenses contaminated with Psedomonas aeruginosa was studied as a proof-of-concept for the hand-held microbial intrinsic fluorescence sensor. We were able to quantify both viable and non-viable cells on the lenses.
Methods: :
In this preliminary study, several pairs of AcuvueTM contact lenses were measured with the sensor after rinsing with sterile saline. They were then inoculated with P. aeruginosa in liquid broth and allowed to incubate at 37°C for 12 hours. These incubated lenses were then rinsed with sterile saline and the initial concentration of the P. aeruginosa biofilm on the lenses was measured with the sensor. One lens of each pair was a control and immediately placed in media for outgrowth. The other lens of the pair was then cleaned and disinfected, according to directions for AMO Easy RubTM, and the effectiveness of the disinfection procedure was then measured with the sensor. All results from the biosensor were confirmed by 12-hour incubation in liquid broth and manual counting with Petroff-Hausser counting chamber.
Keywords: cell survival • detection • bacterial disease