[Evaluation of antimicrobial properties of silicon oil--in vitro studies]

The aim of the study was to evaluate antimicrobial properties of silicon oil in vitro against Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, which are considered the major causative agents of endophthalmitis.

The clinical isolates of representative microorganisms (S. aureus, P. aeruginosa, C. albicans) were selected. The bacteria and the fungus were separately inoculated in PDMS 5000 (produced by AcriMed, Germany). Control inoculations in physiological saline and sugar bouillon were performed. The samples of 0.01 ml from each medium were diluted, according to serial dilution procedure and inoculate on Petri plate dishes 5% sheep blood agar for bacteria and Sabouraud medium for Candida albicans. After 24 h incubations for bacteria and 48 h incubations for fungus, CFUs were counted.

All the microorganisms revealed an apparent decrease in CFUs in PDMS 5000. The total elimination was observed for S. aureus after 5 days. For P. aerugisosa solitary colonies (less than 25 CFUs) were observed up to 7 days. After 7 days of incubation no growth of P. aeruginosa was observed. High C. albicans CFU values were counted up to 3 day of the incubation. After 5 days single fungal colonies were observed. CFUs of the examined microorganisms declined slightly in physiologic saline. A growth pattern similar to the growth curve of microorganisms was observed in sugar boullion.

Our study indicates that silicon oil could have an antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, which are considered the major causative agents of postoperative endophthalmitis.