Impact of slime dispersants and anti-adhesives on in vitro biofilm formation of Staphylococcus epidermidis on intraocular lenses and on antibiotic activities

Infectious endophthalmitis has occurred despite the use of antibiotics in irrigating solutions during implantation of intraocular lenses (IOLs). This infection is generally resistant to antibiotic therapy and, therefore, removal of the implant is necessary before eradication of the infection. This study was designed to assess the role of chosen dispersants and anti-adhesives in inhibiting Staphylococcus epidermidis hydrophobicity, adhesion, slime production and subsequently biofilm formation on IOLs. The relative activity of several potential slime dispersants and anti-adhesives on slime production, hydrophobicity and the adherence of S. epidermidis to IOLs and the degrees to which their effects enhance antibiotic activities were investigated. The MBCs of antibiotics against S. epidermidis strains in a biofilm increased 10-16 times compared with those against bacterial strains in suspension. Addition of slime dispersants or anti-adhesives reversed the susceptibility of the strains in a biofilm to that of bacteria in suspension. Slime production by S. epidermidis strains was significantly diminished by dispersants. Anti-adhesives, hyaluronan, heparin and carpobol 934 exerted less effects on slime production than dispersants. Addition of slime dispersants or anti-adhesives to cell cultures resulted in a significant reduction in bacterial surface hydrophobicity compared with control untreated cultures (at P < 0.001). Reduction of slime production and bacterial surface hydrophobicity led to a marked decrease in the adherence of S. epidermidis to IOLs. Slime dispersants were more effective at reducing bacterial adherence than anti-adhesives. Simultaneous use of antibiotics with slime dispersants or anti-adhesives will exert a more beneficial effect during IOL implantation.