The effects of human tear electrolytes on the viability and hydrogel colonization of Pseudomonas aeruginosa and Staphylococcus aureus

This study was designed to evaluate the effects of the inorganic electrolyt es present in human tear film on the viability and colonization of bacteria to hydrogels. Pseudomonas aeruginosa and Staphylococcus aureus were used i n these experiments. A D-value test was performed to investigate any bacter iostatic effect by measuring the reduction of viable test microorganisms ov er time when exposed to the inorganic electrolyte solution. No D-value was calculable for S. aureus in electrolyte solution whereas a D-value of 8.1 h was obtained for P. aeruginosa in electrolyte solution. The D-value data i ndicate that staphylococci have a greater survivability potential in a hype rtonic environment than do pseudomonads. Bacterial adhesion to high water, ionic hydrogels was studied using the Modified Bobbins Device (MRD). The da ta for P. aeruginosa recovered from the lenses showed an 82% decrease in ba cterial counts in electrolyte solution as compared to bacteria incubated in control solution. In contrast there were slight increases in S. aureus cou nts recovered from the lenses.