1. The study was supported by the Hellenic Copper Development Institute
The effect of copper-coated surfaces on the environmental contamination by pathogenic bacteria in a Greek ICU: A comparative trial M.Souli1, A.Antoniadou1, M.Droggari1, I.Mavrou1, A.Antonopoulou1, G.Poulakou1, E.Papadomichelakis1, P.Efstathiou2, H.Giamarellou3, A.Armaganidis1, G.Petrikkos1 1Attikon University Hospital, Athens, Greece; 2Hellenic Copper Development Institute, Athens, Greece; 3Hygeia Hospital, Athens, Greece
K-245
ABSTRACT
Background. The antimicrobial properties of copper are well established. The aim of the study was to evaluate the effect of metallic copper surfaces on the colonization by pathogenic bacteria, in a setting with a very high prevalence of multidrug resistant strains. Methods. A comparative study was conducted in the ICU of Attikon University Hospital, Athens, Greece from September 2011 until February The bedrails of 6 out of 12 ICU beds, the top and handles of the side table, the iv pole stands, the handles of the accessory side cart and the antiseptic dispenser of each one of these beds as well as the handles of the nurse’s cupboards were coated with copper alloy. In the same ICU compartment, coated and similar non-coated surfaces, which served as controls, were sampled 2 or 3 times during the study period. Sampling was performed before cleaning using a standardized technique for colony counting. For quantitative cultures two flocked nylon swabs were used sequentially, enabling us to retrieve as low as 2log10 CFUs. Only clinically important bacteria were evaluated i.e. Gram-negatives, S. aureus and Enterococci. Results. From 136 samples of copper-coated surfaces, 14 (10.3%) were colonized with a mean of 268±1375 (range ) CFU/100cm2 as compared to 37 of 211 (17.5%, p=0.06)) non-copper control surfaces colonized with 1987±13718 (range ) CFU/100cm2. We isolated (coated vs non-coated surfaces) from upper bedrails 90 vs. 307, bottom bedrails 1650 vs , side bedrails 157 vs. 107, side tables 115 vs. 310, iv poles 0 vs. 86, handles of side cart 104 vs and handles of cupboards 106 vs CFU/100cm2. Pathogenic bacteria isolated were MDR A. baumannii, K. pneumoniae, S. marcescens, P. aeruginosa, E. aerogenes, P. mirabilis, E. faecium, E. faecalis and S. dysenteriae. Conclusions. Replacement of high contact materials with copper could reduce the high burden of environmental contamination by pathogenic bacteria in health-care settings.
The sanitizing properties of copper were known and exploited since ancient times but they have received renewed attention over the last decades as laboratory studies have shown that various bacteria, yeasts and viruses are rapidly killed on metallic copper surfaces by "contact killing". In 2008, the USA Environmental Protection Agency registered 300 different copper surfaces as antimicrobial. This supports the hypothesis that replacement of high contact materials with copper could reduce the high burden of environmental contamination in health-care settings. The aim of the study was to evaluate the effect of metallic copper surfaces on the colonization by pathogenic bacteria, in a clinical setting with a very high prevalence of multidrug resistant strains.
Introduction
Results
During the study period, 347 samples were taken
Of 136 samples taken from copper-coated surfaces, 14 (10.3%) were
colonized with a mean of 268±1375 (range ) CFU/100cm2 as
compared to 37 of 211 (17.5%, p=0.06) non-copper control surfaces
colonized with 1987±13718 (range ) CFU/100cm2
Results are shown in Table 1
Pathogenic bacteria isolated were MDR A. baumannii (the predominant
microorganism), KPC-producing K. pneumoniae, S. marcescens,
P. aeruginosa, E. aerogenes, P. mirabilis, E. faecium, E. faecalis (VRE)
and S. dysenteriae
This was a comparative study conducted in the ICU of Attikon University Hospital, Athens, Greece from September 2011 until February The bedrails of 6 out of 12 ICU beds, the top and handles of the side table, the iv pole stands, the handles of the accessory side cart and the antiseptic dispenser of each one of these beds as well as the handles of the nurse’s cupboards were coated with copper alloy. In the same ICU compartment, coated and similar non-coated surfaces, which served as controls, were sampled 2 or 3 times during the study period.
Sampling was done at a specified time point before regular cleaning of the day. Using a sterile template, a 5cm x 5cm area for large objects or a 5cm x 2cm area for small objects was vigorously wiped (side to side using 15 strokes horizontally and 15 strokes vertically) with a sterile flocked nylon swab (Copanitalia, Italy) pre-moistened in broth and a second non-moistened swab. Both swabs were placed in a sterile tube with 3ml of sterile PBS/LT (copper neutralizing broth [Difco, USA]), vortexed for 1 minute and allowed to settle for 5 minutes. The sample was plated quantitatively on McConkey and blood agar plates and colonies of Gram negatives and Gram positives (S. aureus and enterococci) were counted after 48 hours of incubation. Strain typing and susceptibilities to commonly used antimicrobials was evaluated using standard microbiology methods. This technique was able to recover as low as 2log10 colony forming units (CFUs). The microbial burden was determined as CFU/100cm2.
Materials & Methods
Conclusions
Table 1. Microbial burden on copper-coated surfaces compared to uncoated controls in the clinical setting of the study
Item
MeanSD CFU/100cm2 (range)*
Mean copper-coated surfaces CFU as % of uncoated surfaces CFU
Copper-coated
Non-copper coated controls
Upper bed rails
90254.6 (0-720)
307.51198.4(0-4800)
29.3
Lower bed rails
1650 ( )
10290 ( ) 16
Side bed rails
157.5373.9 (0-1200)
106.9414.1 (0-2400)
147.3
Side table
114.5511.1 (0-2400)
309.6905.9 (0-4200)
36.9
iv pole stand
85.7314.7 (0-1200)
Handles of side cart
103.5502.5 (0-2700)
5464.924936 ( )
1.9
Antiseptic dispenser
Handles of nurse’s cupboard
705.9 (0-6000)
1700 ( )
41.5
A higher mean microbial burden of pathogenic bacteria were recovered from
uncoated versus copper alloy-coated surfaces surrounding patients in an ICU setting,
with one exception
The copper alloy coating reduced the colonization of highly-touched surfaces by 60-
100%, with one exception
A trend was noted for fewer copper-coated surfaces to become colonized by
pathogenic bacteria
Replacement of high contact materials with copper could reduce the high burden of
environmental contamination by pathogenic bacteria in health-care settings
Acknowledgment
The study was supported by the Hellenic Copper Development Institute
* Minimum detection limit: 2log10 colony forming units (CFUs).
Contact Information: Maria Souli, Attikon University Hospital, 1 Rimini Street, Chaidari, Athens Greece, Tel : , Fax : , E mail: