Bacterial colonization of contact lens cases may be the result of co-aggregation, cohesion and growth promotion by certain bacteria, a recent ARVO study shows. Researchers from the University of New South Wales in Sydney, Australia, set out to evaluate the roles of the various stages of colonization in bacteria associated with contact lens case contamination. They used Staphylococcus epidermidis, Staphylococcus haemolyticus, Micrococcus luteus and Acinetobacter radioresistens to test bacterial activity in relation to cohesion, ability to interfere with the growth of other isolates and co-aggregation.

Results showed co-aggregation may be involved in cohesion between strains of A. radioresistens or M. luteus and Staphylococci. Additionally, “the ability of small numbers of A. radioresistens or Staphylococci to promote each other’s growth may also be involved in cohesion and hence biofilm formation,” the study said. As such, the researchers believe targeting specific bacteria in future efforts could reduce contact lens-induced adverse ocular events. 

“Knowledge of these interactions may aid in the rationale design of strategies to reduce adhesion and biofilm formation by bacteria in contact lens cases,” the study concluded. “This research will provide a framework for future studies that examine how to reduce biofilm formation in contact lens cases.”

“Understanding bacterial interaction in the lens case of contact lens wearers is fundamental in establishing strategies to minimize adhesion and biofilm formation in the lens case,” says Joseph P. Shovlin, OD, of Scranton, PA. “Targeting specific bacteria commonly found as contaminants in the case seems to provide a new infrastructure in an attempt to minimize adverse events related to these contaminants. Biofilms allow pathogens to communicate among each other and every effort should be undertaken to reduce biofilm formation commonly found in cases of lens wearers.”