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2018 Abstracts

Povidone-Iodine Vapor Kills MRSA

Benjamin Ogilvie; Jon Mitton; Jordan Tucker, Brigham Young University

Povidone-iodine is an antiseptic that is frequently used to clean skin prior to surgery. Current FDA regulations require that hospitals dispense povidone-iodine from single-use bottles, rather than large, multi-use containers, to prevent microbial contamination. This results in hospitals generating lots of product waste. However, if povidone-iodine vapor can kill microbes, then multi-use containers may be safe to use, since any bacteria that contaminated the inside of the container would soon die. The purpose of this research was to determine whether vapor from povidone-iodine could kill methicillin-resistant Staphylococcus aureus (MRSA), a common cause of hospital-associated infections. Povidone-iodine antiseptics contain povidone, a polymer, complexed with iodine. In solution, these antiseptics release iodine gradually, allowing them to kill microbes while causing less damage to human tissue than would a concentrated iodine solution. In this experiment, metal cylinders were coated with MRSA. Then, these cylinders were placed inside of small plastic bottles containing Betadine, a povidone-iodine antiseptic. The metal cylinders did not come into contact with liquid Betadine, but they were exposed to Betadine vapor, making it possible to assess the vapor’s antimicrobial properties. After 20 minute, 40 minute, and 80 minute intervals, cylinders were removed from specified bottles and placed into glass tubes containing sterile saline. These tubes were then sonicated to remove the bacteria from the metal cylinders, and the resulting solutions were assayed for visible bacteria via spread plating. Each colony that grew on the agar indicated a single surviving bacterium. Taking the dilution into account made it possible to assess how many bacteria were present in the original suspension and, in turn, on each metal cylinder following treatment with Betadine vapor. Overall, this data showed how effectively the Betadine vapor killed MRSA bacteria. In summary, this experiment demonstrated that the Betadine vapor killed MRSA in a time-dependent manner; most samples demonstrated a 5-log reduction after 80 minutes of Betadine vapor exposure. This bacterial death is likely caused by volatilized iodine, which is surprising, as a typical Betadine solution only has approximately 1% available iodine in solution. Iodine is moderately volatile, having roughly the same heat of vaporization as water (41.57 kJ/mol). A typical multi-use Betadine container probably has a significant amount of iodine vapor inside, making it unlikely to support microbial contamination for very long. It may be possible to safely re-use Betadine containers in a controlled manner.