(LR-023) The Effect of Copper-iodine Complex Solution on the Killing and Antimicrobial Persistence of Two Candida Species (C. Albicans and C. Auris): An in vitro Model

Richard Smith, PhD; Julian Bejarano, PhD; Oanh Nguyen, MSc; Chandre Van De Werwe, PhD

Introduction: Yeast infections, such as that produced by Candida spp., are common in chronic wounds and burns. C. albicans-related infection has multiple treatment options, both topical and pharmacological. However, C. auris is an emerging World Health Organization threat with no known pharmacologic treatment course and can lead to morbidity and mortality. The purpose of this in vitro study is to demonstrate the killing effect and antimicrobial persistence of copper iodine irrigation solution (CICS) on two yeast species.

Methods: Each test article (CICS or 1 ppm Lugol’s iodine) was inoculated with ~10⁵ CFU/mL of C. albicans or C. auris.
After a 10-minute exposure time (sample 0 mins), samples were neutralized, diluted, and plated. To assess the antimicrobial persistence, the same samples were rechallenged by renoculating~10⁵ CFU/mL of each organism
at 10 mins, 2 hours, 5 hours, and 24 hours and neutralized after a 10-minute exposure time.

Results:

Organism	Test substance	Average log reductions at each rechallenge interval
		0 mins	10 mins	2 hours	5 hours	24 hours
C. albicans	CICS	5.5±0.2	5.5±0.2	5.5±0.2	5.5±0.2	5.5±0.2
	1 ppm Lugol's Iodine	5.5±0.2	5.5±0.2	0.1±0.2	0.0±0.2	-0.4±0.3
C. auris	CICS	5.6±0.1	5.6±0.1	5.6±0.1	5.6±0.1	5.6±0.1
	1 ppm Lugol's Iodine	5.6±0.1	1.7±0.6	0.2±0.2	0.1±0.1	0.1±0.1

Test organism	Test substance	Exposure interval	Rechallenge Interval	Average log reduction (log (CFU/mL)	Percent reduction (%)
C. albicans	CICS	10 mins	0 mins	5.5±0.2	>99.9998
			10 mins	5.5±0.2	>99.9998
			2 hours	5.5±0.2	>99.9998
			5 hours	5.5±0.2	>99.9998
			24 hours	5.5±0.2	>99.9998
	1 ppm Lugol's iodine	10 mins	0 mins	5.5±0.2	>99.9998
			10 mins	5.5±0.2	>99.9998
			2 hours	0.1±0.2	47.7760
			5 hours	0.0±0.2	43.2997
			24 hours	-0.4±0.3	-39.1496
C. auris	CICS	10 mins	0 mins	5.6±0.1	99.9998
			10 mins	5.6±0.1	99.9998
			2 hours	5.6±0.1	99.9998
			5 hours	5.6±0.1	99.9998
			24 hours	5.6±0.1	99.9998
	1 ppm Lugol's iodine	10 mins	0 mins	5.6±0.1	99.9998
			10 mins	1.7±0.6	99.9281
			2 hours	0.2±0.2	41.1196
			5 hours	0.1±0.1	16.7489

High antimicrobial efficacy ( >99.999% or 5 log reduction) of CICS was demonstrated when rechallenged by reinoculations over 24 hours for both C. albicans and C. auris. Lugol’s iodine showed loss of activity in 2 hours of exposure.





Discussion:
Copper-Iodine Complex Solution demonstrated an effective kill rate and antifungal persistence in vitro with both C. albicans and C. auris. This has significant implications for acute and chronic wounds, trauma and burns, especially when there is no present medicinal treatment for C. auris. Further studies are warranted to support these findings.