The pandemic of hospital-acquired infections caused by methicillin-resistant Staphylococcus aureus (MRSA) has declined, but the evolution of strains with enhanced virulence and toxins and the increase of community-associated infections are still a threat. In previous studies, 10 7 MRSA bacteria applied as simulated droplet contamination were killed on copper and brass surfaces within 90 min. However, contamination of surfaces is often via finger tips and dries rapidly, and it may be overlooked by cleaning regimes (unlike visible droplets). In this new study, a 5-log reduction of a hardy epidemic strain of MRSA (epidemic methicillin-resistant S. aureus 16 [EMRSA-16]) was observed following 10 min of contact with copper, and a 4-log reduction was observed on copper nickel and cartridge brass alloys in 15 min. A methicillin-sensitive S. aureus (MSSA) strain from an osteomyelitis patient was killed on copper surfaces in 15 min, and 4-log and 3-log reductions occurred within 20 min of contact with copper nickel and cartridge brass, respectively. Bacterial respiration was compromised on copper surfaces, and superoxide was generated as part of the killing mechanism. In addition, destruction of genomic DNA occurs on copper and brass surfaces, allaying concerns about horizontal gene transfer and copper resistance. Incorporation of copper alloy biocidal surfaces may help to reduce the spread of this dangerous pathogen.
Intrinsic penicillin resistance and acquisition of resistance to methicillin in the 1980s by Staphylococcus aureus led to a pandemic of infections worldwide. Initially, the majority of infections were contracted in health care environments, but incorporation of measures to control the spread, including preadmission screening, decolonization, improved disinfection, and antibiotic treatment, have stemmed the tide (1). The increased use of antibiotics required for the epidemic of infections caused by Gram-positive pathogens has allowed the evolution of multidrug-resistant Gram-negative pathogens, effectively transforming some commensal gut bacteria into potential killers. However, new strains of S. aureus that have acquired further virulence factors and toxins or that have adapted to a specific environment, for example, an increased ability to cause bacteremia (2), are still a considerable threat. There is now widespread community-associated methicillin-resistant S. aureus (CA-MRSA), and infections can spread within households, day care centers, and schools (3). In addition, Giuffre et al. observed an increasing incidence of MRSA in neonates (4). The ability of some strains of MRSA to revert to methicillin-susceptible isolates, particularly in skin and soft tissue infections, has been observed (5).Colonization with MRSA increases the risk of MRSA infection, particularly following illness, surgical procedures, and treatment with immunosuppressive drugs. Colonization and/or infection may also occur from touching contaminated surfaces. In the community, a recent study observed that 58% and 82% of surfaces in 19 f...