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Although previous studies have reported on aspirate cultures after cataract surgery,1–3 the minimum strength of inoculum causing endophthalmitis or the route through which the pathogen enters the eye remains unclear. A recent study reported the use of operative face masks to have a significant effect on the bacterial load falling on the operative site.4 Although cataract extraction and lens implant is a procedure of relatively short duration, airborne bacterial contamination of surgical gloves is still possible from the environment in the operating theatre. We designed a study to determine if antiseptic scrubs of surgical gloves between cataract surgeries will reduce bacterial load to levels equivalent to a new pair of sterile gloves.
We obtained approval of the ethics committee of the institute before initiating the study, and obtained necessary consent from participating subjects. Cataract surgery with intraocular lens implants was carried out through a self sealing scleral tunnel incision and manual expression of the lens. We randomly selected operating surgeons for the study. Each operating surgeon underwent a preoperative hand scrub repeated twice using chlorhexidine 0.5% solution for 5 minutes. Each operating surgeon wore a face mask, and donned a sterile surgical gown before gloving. Surgeons used commercially available pre-packed sterile powdered latex surgical gloves in the operating room. Each surgeon used 70% isopropyl alcohol solution applied for 30 seconds to scrub gloves between surgeries. None of the surgeons left the operating area in between surgeries. We used sterile cotton moistened with saline to take swabs from the gloves. Swabs were taken from the pre-packed sterile gloves after opening the pack in the operating room, and streaked across a blood agar plate. Swabs were collected from the fingertips and webs of fingers of both hands at random intervals after the first surgery, and streaked across independent blood agar plates. The surgeons also streaked separate blood agar plates with a random fingertip of both hands at the conclusion of their operating list before removal and disposal of the gloves. Surgical gloves once removed were not used again. Additional swabs were collected from the surgical gown over the elbows and abdominal area of the surgeon at random intervals and streaked across blood agar plates. Swabs were also collected from the handles of operating microscopes at random intervals. The swabs, after inoculation into blood agar plates, were placed in brain-heart infusion broth.
The plates were incubated for 5 days at 37°C in a 5% carbon dioxide incubator. The plates were read by a microbiologist and declared culture negative if there was no evidence for growth at the end of 5 days. We defined culture positive as the presence of bacterial colonies on the streaked areas, or where the finger impressions were placed. Any species of bacteria were considered significant. The presence of turbidity in the brain-heart infusion broth, if any, was noted.
Surgeons included for the study performed 850 cataract surgeries with intraocular implants in a 5 day period. The mean number of cataract surgeries performed in a day by surgeons included for the study was 16.7 (SD 10.0) (range 4–30, median 15). The duration of surgery ranged from 1–5 hours (mean 6.0 (2.4) cases per hour). None of the culture plates showed any positive growth after 5 days for swabs taken from the sterile gloves, from the gloves in between cataract surgeries, and from the gowns and handles of operating microscopes.
There are, however, several issues to be considered. None of our surgeons had left the operating area in between cataract surgeries; we are not clear if we would have obtained the same results if surgeons reused the same gloves after leaving the operating area. Previous studies have reported the possibility of microscopic punctures to the gloves.5–7 Although modern cataract surgery is a “no ocular touch” technique, the possibility of microscopic droplet inoculation of the gloves with ocular fluid or other fluids cannot be ruled out.8 A previous study has reported that catheter contamination rates could be reduced without additional risk or cost by rinsing gloved hands in a solution of 0.5% chlorhexidine in 70% alcohol before handling the catheter.9 We do not however recommend antiseptic scrubs as an alternative to change of gloves because a sterile prepacked glove can reduce even a theoretical risk of contamination leading to endophthlamitis. However, in resource poor situations, antiseptic scrubs of gloves can be an alternative to change of gloves in between cataract surgeries.
Aravind Medical Research Foundation, Madurai, supported this study.
Financial interest: none.