Elucidation of antibiotic effectiveness against Staphylococcus epidermidis during intraocular lens implantation.

The effect of various antimicrobial agents commonly used in irrigating solutions on the hydrophobicity and adherence of Staphylococcus epidermidis ATCC 14990 was investigated. The longest post-antibiotic effect (PAE=3.2 h) was obtained with gentamicin followed by ciprofloxacin (2.7 h), clindamycin (2.2 h), ceftazidime (1.8 h) and vancomycin (1.6 h). The post-antibiotic effect on surface hydrophobicity of cells previously treated with gentamicin, ciprofloxacin, or clindamycin for 120 min resulted in a substantial decrease in affinities to hexadecane (31.4, 28.5 and 27%, respectively) compared with control untreated cells. Less effect was noted with cells previously treated with ceftazidime or vancomycin (20.5 and 15.8%, respectively). Similar but less marked results were obtained when the cells were exposed to antibiotics for 30 or 60 min. The post-antibiotic effect on adherence of cells to both intraocular lenses and to epithelial cells showed that adherence to lenses decreased as the time of exposure to antimicrobial agents increased. Adherence was greatly diminished with cells treated with gentamicin or ciprofloxacin compared with control untreated cells. Adherence was less affected by clindamycin, ceftazidime and vancomycin. The data supported the use of antimicrobial agents in irrigating solution during intraocular surgery, since, reduced adherence (colonization) and might result in a lower incidence of endophthalmitis.