Abstract
Purpose :
The purpose of this study was to evaluate the adhesion of emerging pathogens to a conventional hydrogel and a silicone hydrogel contact lens (CL) material, under the influence of an artificial tear solution (ATS) containing a variety of components commonly found in human tears.
Methods :
An in-vitro study was conducted using four different bacterial strains Pseudomonas aeruginosa ATCC 9027, Achromobacter xylosoxidans ATCC 27061, Delftia acidovorans ATCC 17438 and Stenotrophomonas maltophilia ATCC 17676. Two different CL materials (n=3) etafilcon A (ACUVUE® 2®) and senofilcon A (ACUVUE® OASYS®) were included in this study. The test and control CLs were soaked in an ATS and phosphate buffered saline respectively for 12 h at 37°C, prior to their exposure to bacteria (inoculum of 106 CFU/mL) for 18 h at 37°C. After the incubation period, the total and viable counts of bacteria recovered from CLs were determined using a radio-labelling technique and plate count method respectively. Each experiment is repeated three times. Log transformations were used for data analysis.
Results :
In the control group, the total counts of A. xylosoxidans and P. aeruginosa recovered from etafilcon A and senofilcon A CLs were significantly (p≤0.043) higher compared to D. acidovorans and there was no significant difference between the two CL materials (p>0.05). After exposure to ATS, the total counts of A. xylosoxidans and P. aeruginosa recovered from etafilcon A remained significantly higher compared to D. acidovorans and S. maltophilia (p≤0.029). However, the total counts recovered from senofilcon A did not vary significantly between different strains (p>0.05). The total counts of D. acidovorans recovered from etafilcon A CLs (mean log CFU/CL± SD, 5.4 ± 0.2) were significantly lower (p=0.035) compared to those recovered from senofilcon A CLs (5.8 ± 0.4); for the remaining strains, the total counts did not vary significantly (p>0.05) between the two CL materials. Among all the strains assessed, S. maltophilia showed the least viability on either CL material (p<0.001), regardless the influence of ATS.
Conclusions :
This study found that under the influence of an ATS, the propensity of emerging pathogens to adhere to a conventional and a silicone hydrogel CL material varied substantially between different test strains.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.