[Search for bacterial contamination of the aqueous humor during cataract surgery with and without local antibiotic prophylaxis].

Purpose: Bacterial contamination of anterior chamber at the end of cataract surgery, was compared between two techniques: extracapsular extraction and phacoemulsification. The effectiveness of preoperative antibiotic eyedrops using Norfloxacine 0.3% (Chibroxine) was also evaluated.

Method: The study focused on 101 patients grouped according to surgical technique and presence of preoperative antibiotic eyedrops. Conjunctival sampling was made the day prior the surgery, as well as in the operating room, after skin and conjunctival desinfection with povidone iodine in all the patients included in the study. Aqueous humour was collected at the end of surgery.

Results: Eight samples out of 101 were positive which represents 7.9% of the cases. In 75% of the cases, the anterior chamber aspirate showed a different germ or non-recurrent germ in the second conjunctival sample. None of the included patients developed endophthalmitis. The two most frequent pathogens were Propionibacterium acnes in 62.5% of the cases, and Staphylococcus epidermidis in 50%. Another pathogen was found in a culture environment: Micrococcus roseus. In two samples, two different bacteria grew: Propionibacterium acnes and Staphylococcus epidermidis. Whatever the surgical technique, no statistically significant bacterial contamination was found. There was no significant statistical difference between patients who had local antibiotic eyedrops and those who did not.

Conclusion: This study confirms the poor reliability of local antibiotic eyedrops to prevent surgical contamination. Furthermore performing an anterior chamber aspirate at the end of the surgery for risk patients would help the physician identify the pathogens involved in endophthalmitis in order to begin antibiotic treatment as soon as possible.