Effect of lidocaine gel on povidone-iodine antisepsis and microbial survival
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John H Boden1, Mary L Myers, Thomas Lee
1Department of Ophthalmology, Madigan Army Medical Center, Tacoma, Washington 98431, USA. john.boden@amedd.army.mil
Purpose:
To determine whether the use of lidocaine gel prior to povidone-iodine antisepsis is associated with increased microbial survival.
Setting:
Ophthalmology Department, Madigan Army Medical Center, Fort Lewis, Washington, USA.
Methods:
A standardized suspension of Staphylococcus epidermidis was used to inoculate 5 blood agar plates that served as a control. A second group of 5 blood agar plates was inoculated, and then lidocaine gel was applied to the plates. A third group of 5 blood agar plates was inoculated, lidocaine gel was applied, and then povidone-iodine 5% was applied and allowed to cover the plates. A fourth group of 5 blood agar plates was inoculated, and then povidone-iodine 5% was allowed to cover the plates. Cultures of Staphylococcus aureus, Pseudomonas aeruginosa, and Haemophilus influenza were tested in a similar fashion. Microbial growth was evaluated after 24 hours.
Results:
The number of colony forming units (CFUs) was similar in the control group and the S epidermidis, S aureus, and P aeruginosa lidocaine only and lidocaine with povidone-iodine groups. In these groups, each plate grew between 200 CFUs and 300 CFUs. In the Haemophilus influenza series, the lidocaine with povidone-iodine group had fewer CFUs than the control group. In all 4 series, the povidone-iodine only group had the least amount of CFUs, ranging from 0 to 6.
Conclusions:
The use of lidocaine gel before application of povidone-iodine 5% resulted in decreased effectiveness of antisepsis and increased microbial survivability. The increase in microbial survivability may increase the risk for postoperative infection in ocular surgery performed under topical anesthesia.
Insights
Lidocaine gel before povidone-iodine antisepsis may increase microbial survival, potentially raising infection risk in ocular surgery. Further research is needed to confirm these findings and guide clinical practice.
Area of Science:
- Ophthalmology
- Microbiology
- Infectious Disease
Background:
- Topical anesthesia is common in ophthalmic procedures.
- Povidone-iodine is a widely used antiseptic agent.
- The interaction between lidocaine gel and povidone-iodine efficacy is not well understood.
Purpose of the Study:
- To investigate if lidocaine gel use prior to povidone-iodine antisepsis impacts microbial survival rates.
- To assess the combined effect of lidocaine gel and povidone-iodine on common ocular pathogens.
Main Methods:
- In vitro study using blood agar plates inoculated with Staphylococcus epidermidis, Staphylococcus aureus, Pseudomonas aeruginosa, and Haemophilus influenza.
- Plates were treated with lidocaine gel, povidone-iodine 5%, or a combination.
- Microbial growth (colony forming units) was quantified after 24-hour incubation.
Main Results:
- Lidocaine gel alone did not significantly alter microbial survival compared to controls for most bacteria.
- The combination of lidocaine gel and povidone-iodine showed reduced antimicrobial activity against Haemophilus influenza compared to povidone-iodine alone.
- Povidone-iodine alone demonstrated the highest antimicrobial efficacy, with minimal to no microbial growth observed.
Conclusions:
- Pre-application of lidocaine gel may diminish the effectiveness of povidone-iodine antisepsis.
- This interaction could potentially lead to increased microbial survivability.
- Enhanced microbial survival may elevate the risk of postoperative infections in patients undergoing ocular surgery with topical anesthesia.
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