
The demand for novel approaches for prevention of hospital-associated infections (HAIs) has recently focused on intrinsically antimicrobial surfaces such as copper. We assessed the bactericidal activity for common nosocomial pathogens of various copper surfaces over time in comparison to stainless steel.
Methods:
Methicillin-susceptible Staphylococcus aureus (MSSA, ATCC 29213) and clinical isolates of Vancomycin-resistant Enterococcus faecium and Acinetobacter baumannii were evaluated. Products tested included 80% copper (Cu)/20% nickel (Ni) alloy; 90% Cu/10% Ni; 100% Cu; and antimicrobial Copper products from LuminOre Inc. (64 % Cu , 11% Ni, 20% Other ingredients) and EoS protective surface from Cupron( 16% Cu(i) Oxide/ 84% Other ingredients. Stainless steel was the negative control.
Organisms grown on sheep blood agar (BAP) were suspended in saline and standardized to a density approximating 1.5 x 108 CFU/mL. A 10 uL aliquot was applied to 4 separate cleaned and sterilized coupons (1 cm2) which were incubated at room temperature for either 0, 30, 60 or 120 minutes. After incubation, the coupon was placed in 1 mL D/E buffer containing glass beads and vortexed. An aliquot was removed, serially diluted and plated onto BAPs in duplicate to determine surviving CFU per coupon. At least 4 replicates of each coupon were tested.
Ranking of products was performed by fitting exponential decay models to the CFU/coupon and ranking kill rates. Statistical differences between kill rates were determined by two-tailed z-tests on kill rates.
Results:
For all three organisms, all copper surfaces demonstrated statistically significant enhanced killing compared with stainless steel, although there were differences between organisms and surfaces. For MSSA, LuminOre Copper-colored pebbled surface killed best (p=0.035 compared with next highest ranked sample); for VRE, LuminOre Nickel-colored smooth (p=0.01); for Acinetobacter, all Copper materials were comparable (p=0.006 compared with stainless steel).
Conclusion:
All copper products demonstrated significantly enhanced killing compared with stainless steel, with two LuminOre products showing greatest efficacy for MSSA and VRE.

D. Z. Uslan,
None
R. M. Humphries, None
E. Alvarez, None
M. Maldanado, None
P. Sinsheimer, None
V. Gupta, None
D. Huynh, None
R. Brookmeyer, None
N. Abraham, None