Bacterial contamination during extracapsular cataract extraction. Prospective study on 200 consecutive patients

Area of Science:

• Ophthalmology
• Microbiology
• Surgical Infections

Background:

• Postoperative endophthalmitis is a severe complication of eye surgery.
• Infections by 'nonpathogenic' organisms (e.g., Propionibacterium acnes, coagulase-negative staphylococci) are increasingly significant.
• Identifying microbial contamination sources is crucial for preventing surgical site infections.

Purpose of the Study:

• To investigate the prevalence of microbial contamination in the anterior chamber during cataract surgery.
• To correlate anterior chamber contamination rates with surgical techniques, specifically phacoemulsification versus conventional cataract extraction.
• To assess the risk of postoperative endophthalmitis development in relation to microbial presence.

Main Methods:

• Prospective study of 200 patients undergoing eye surgery.
• Collection of preoperative conjunctival swabs and intraoperative anterior chamber aspirates (start and end).
• Microbiological analysis of all samples for aerobic and anaerobic bacteria and fungi.

Main Results:

• 75% of preoperative swabs showed contamination, primarily with coagulase-negative staphylococci.
• 28% of anterior chamber aspirates were culture-positive, also predominantly for coagulase-negative staphylococci.
• Contamination of aqueous humor was significantly lower (p < 0.03) with phacoemulsification compared to other techniques.

Conclusions:

• Despite significant microbial contamination in anterior chamber aspirates, no cases of postoperative endophthalmitis occurred, likely due to small inoculum size and host defenses.
• Phacoemulsification cataract extraction is associated with reduced intraoperative microbial contamination of the anterior chamber.
• Surgical technique plays a role in minimizing microbial contamination during eye surgery, potentially reducing endophthalmitis risk.