Reduced adhesion of Staphylococcus aureus to ZnO/PVC nanocomposites

In hospitals and clinics worldwide, medical device surfaces have become a rapidly growing source of nosocomial infections. In particular, patients requiring mechanical ventilation (and, thus, intubation with an endotracheal tube) for extended lengths of time are faced with a high probability of contracting ventilator-associated pneumonia. Once inserted into the body, the endotracheal tube provides a surface to which bacteria can adhere and form a biofilm (a robust, sticky matrix that provides protection against the host immune system and antibiotic treatment). Adding to the severity of this problem is the spread of bacterial genetic tolerance to antibiotics, in part demonstrated by the recent and significant increase in the prevalence of methicillin-resistant Staphylococcus aureus. To combat these trends, different techniques in biomaterial design must be explored. Recent research has shown that nanomaterials (materials with at least one dimension less than 100 nm) may have the potential to prevent or disrupt bacterial processes that lead to infections. In this study, polyvinyl chloride (PVC) taken from a conventional endotracheal tube was embedded with varying concentrations of zinc oxide (ZnO) nanoparticles. S. aureus biofilms were then grown on these nanocomposite surfaces during a 24-hour culture. Following this, biofilms were removed from the surfaces and the number of colony forming units present was assessed. Bacterial proliferation on the samples embedded with the highest concentration of ZnO nanoparticles was 87% less when compared to the control, indicating that this technique is effective at reducing biofilm formation on PVC surfaces without the use of antibiotics.