Increased Resistance of Contact Lens-Related Bacterial Biofilms to Antimicrobial Activity of Soft Contact Lens Care Solutions

Abstract

PURPOSE To determine if clinical and reference strains of Pseudomonas aeruginosa, Serratia marcescens, and Staphylococcus aureus form biofilms on silicone hydrogel contact lenses, and ascertain antimicrobial activities of contact lens care solutions. METHODS Clinical and American Type Culture Collection (ATCC) reference strains of Pseudomonas aeruginosa, Serratia marcescens, and Staphylococcus aureus were incubated with lotrafilcon A lenses under conditions that facilitate biofilm formation. Biofilms were quantified by quantitative culturing (colony forming units, CFUs), and gross morphology and architecture were evaluated using scanning electron microscopy (SEM) and confocal microscopy. Susceptibilities of the planktonic and biofilm growth phases of the bacteria to five common multipurpose contact lens care solutions and one hydrogen peroxide care solution were assessed. RESULTS P. aeruginosa, S. marcescens, and S. aureus reference and clinical strains formed biofilms on lotrafilcon A silicone hydrogel contact lenses, as dense networks of cells arranged in multiple layers with visible extracellular matrix. The biofilms were resistant to commonly used biguanide preserved multipurpose care solutions. P. aeruginosa and S. aureus biofilms were susceptible to a hydrogen peroxide and a polyquaternium preserved care solution, whereas S. marcescens biofilm was resistant to a polyquaternium preserved care solution but susceptible to hydrogen peroxide disinfection. In contrast, the planktonic forms were always susceptible. CONCLUSIONS P. aeruginosa, S. marcescens, and S. aureus form biofilms on lotrafilcon A contact lenses, which in contrast to planktonic cells, are resistant to the antimicrobial activity of several soft contact lens care products.

Risk factors for contact lens-related microbial keratitis in Singapore

“…[25][26][27] Certain polymeric biguanide-based care solutions have been demonstrated to be less effective against bacterial biofilms in comparison with hydrogen peroxide or polyquaternium-based solutions. 28 In addition, reduction in microbial efficacy of this product has been reported when used for the storage of contact lenses in lens cases over a prolonged period of time. 29 The increased risk identified with the use of MPS A in both clinical and laboratory studies may suggest failure to achieve a suitable level of disinfection efficacy particularly in the hands of the wearer.…”

Microbial biofilm in human health - an updated theoretical and practical insight

“…Literature data show that between 20 and 80% of persons wearing contact lenses may acquire corneal infections with fungi, bacteria, amoebae, originating from biofilm contamination of these devices and the cases in which they are stored (1). In a research conducted by Szczotka-Flynn et al, lotrafilcon A silicone hydrogel contact lenses were found to be contaminated with both reference and clinical strains of Serratia marcescens, P.aeruginosa and S.aureus, developing within biofilms and which resisted to solutions of biguanide compounds, common care solutions for such devices (18).…”

“…Once microbial colonization occurs on such medical devices, chronic, slowly evolving, persistent infections may develop. The incidence of such complications is expected to rise with the increased use of implanted medical devices and equipments (3,10,16,17,18).…”

Component Analysis of Multipurpose Contact Lens Solutions To Enhance Activity against Pseudomonas aeruginosa and Staphylococcus aureus

“…Evaluation of the effect of the C30/P5/E5000 formulation on contact lens biofilms. Biofilm studies employed a published technique (12). Briefly, senofilcon A lenses were washed with PBS and then placed in 12-well tissue culture plates with 4 ml of bacterial cell suspensions; overnight cultures were washed twice with PBS and diluted in PBS to reach an absorbance value of 0.1 at 660 nm.…”