Anti-adhesive, bactericidal and lytic effects of taurolidine on biofilm formation: in vitro endophthalmitis model.

Abstract

Purpose: To assess bactericidal and anti-adhesion in vitro properties of taurolidine (TL) in order to estimate its relevance to endophthalmitis prophylaxis. To study the efficiency of taurolidine for chronic endophthalmitis treatment.

Methods: Staphylococcus epidermidis was used as infectious agent. Taurolidine was used at 1mg/ml. To obtain bacterial killing curves, the first experiments were performed in a 103 CFU/ml bacterial suspension containing no intraocular lenses (IOL). Some bacterial suspensions were exposed to the TL, while the others were not. To determine bacterial adherence, IOLs were either immersed in the bacterial suspension (103 CFU/ml) without TL, or in the presence of 1mg/ml of TL. At various times of a 24 hours period, IOLs were taken from this environment and the bound bacteria were removed by sonication and counted. The last experiments consisted in incubating IOLs in a bioreactor designed to replicate intraocular conditions and bacterial inoculation in order to produce a 42 hours biofilm growth. Some IOLs were taken from the environment for bacterial counting before TL administration (controls). Then TL was injected in the system and after 24 hours some IOLs underwent bacterial counting. Testing was repeated 24 hours after a second injection of TL on the remaining IOLs. At each time of the study, some IOLs were examined by SEM.

Results: A bactericidal effect of the TL solution was found during the first hours of incubation, with a minimum of a 3 log reduction after 11 hours. At 3 and 6 hours, TL reduced the quantity of bacteria adhering to IOLs by 83% whereas the quantity of bacteria present in suspension was only reduced by 24% and 48%, respectively. Taurolidine reduced significantly the quantity of biofilm on IOLs taken from the bioreactor, whereas biofilm quantity to IOLs before treatment was very high. Our results were confirmed by SEM study.

Conclusions: This study showed the bactericidal and the anti-adhesive properties of TL suggesting its relevance to endophthalmitis prevention. By using TL, we obtained a high reduction of biofilm adhering to IOLs suggesting that intraocular injections of TL could be an alternative to invasive treatments in chronic endophthalmitis. In vivo animals studies are needed to confirm these results before considering any clinical study.

Keywords: 513 endophthalmitis • 433 bacterial disease • 445 cataract