The rapid increase of antibiotic-resistant strains of bacteria is a serious threat to human health. Only two antibiotics were approved between 2008 and 2012 and, with treatment-resistance casting uncertainty over the life cycle of new antibiotic drugs, pharmaceutical companies have restricted investment in antibiotic development. The paucity of new drugs has prompted many to turn to engineering to achieve antimicrobial surfaces less susceptible to resistance.
Researchers at Purdue University in Indiana, have created a laser treatment method that can engineer antimicrobial properties into surfaces. The new technique could be used to reduce infections acquired from clinical and hospital surfaces such as implants, doorknobs, keyboards and other medical equipment.
‘We developed a one-step laser-texturing technique that effectively enhances the bacteria-killing properties of copper’s surface,’ said Rahim Rahimi, an assistant professor of materials engineering at Purdue University.
The technique relies on ‘contact killing’, whereby copper surfaces cause bacterial membranes to rupture and inactivate. By nanoengineering the copper surface with a laser treatment, the team increased the ‘contact killing’ surface area of the material. Their nanoengineered copper was able to effectively and quickly kill four different bacterial strains, including antibiotic-resistant MRSA, a common and problematic hospital-acquired infection.
Hospital-acquired infections place a significant burden on public health. In the EU, the European Centre for Disease Prevention and Control estimates that roughly 4.1 million acute care patients contract a hospital-acquired infection every year, resulting in 37,000 deaths. In the US, some two million infections annually cost the healthcare sector roughly $28-45 billion.
Clinical research shows that copper can also be used to destroy viruses, such as influenza, norovirus, hepatitis C, and even HIV. While this technology is yet to be applied for antiviral purposes in clinical settings, copper surfaces have been effectively used in Finnish facilities to reduce counts of S. aureus, a common hospital-acquired infection. Copper surfaces have also reduced bacteria numbers on often-touched surfaces in intensive care units in the US.
Medical history is laced with examples of where transmissions through hospitals have accelerated epidemics; during the norovirus outbreak of 2009, norovirus was detected on 31 per cent of hospital surfaces, including trolleys, door handles, computer keyboards, and soap dispensers; during the SARS epidemic, 20 per cent of all infected persons were medical personnel. In light of recent events, nanoengineering looks like an increasingly viable solution.