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Bacterial contamination during extracapsular cataract extraction. Prospective study on 200 consecutive patients
S F Egger1, V Huber-Spitzy, C Scholda
12nd Department of Ophthalmology, University of Vienna, Austria.
Abstract:
Postoperative endophthalmitis remains one of the most devastating complications of eye surgery. In recent years infections with so called 'nonpathogenic' organisms like Propionibacterium acnes or coagulase-negative staphylococci have gained in importance. 200 patients were included in this study, from whom preoperative smears of the conjunctiva and intraoperative aspirates of the anterior chamber (at the start and at the end of the operation) had been taken. All samples were investigated for aerobe and anaerobe microorganisms and fungi. 75% of the preoperative smears had been contaminated, with coagulase-negative staphylococci the most commonly isolated bacteria. But, in addition, 28% of the patients had culture-positive anterior chamber aspirates, also with coagulase-negative staphylococci as the most frequent organisms. In all cases inoculum sizes were extremely small (10-20 c.f.u./ml). Probably because of this small inoculum, but also due to the bacteriocidal qualities of the aqueous humor and the integrity of the posterior capsule sac, in no case had postoperative endophthalmitis developed. For the first time, our study tried to correlate the contamination of the anterior chamber aspirate to the used operation technique: first results show that the contamination of the aqueous humor is significantly lower (p < 0.03) if the cataract extraction is performed by phacoemulsification than if done without.
Insights
Eye surgery complications like postoperative endophthalmitis can arise from common bacteria. Phacoemulsification cataract extraction significantly reduces anterior chamber contamination compared to other methods.
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.