Methicillin Resistance, Biofilm Formation and Resistance to Benzalkonium Chloride in Staphylococcus aureus Clinical Isolates

Although the mechanisms are poorly understood, there is evidence that biofilm-associated resistance may be related to modified nutrient environments, leading to suppression of growth rate within the biofilm, interaction between exopolymer matrices and the antimicrobial, as well as the development of biofilm-specific phenotypes [3]. In comparative antimicrobial susceptibility studies, many common gram-negative and gram-positive bacterial pathogens that produce biofilms show significantly higher antibiotic resistance rates than in their planktonic state [4,5] but also higher resistance to disinfectants [6-8]. Correct practice of disinfectant use within hospitals, including hand hygiene, has long been considered the most appropriate first line of defence to limit infection outbreaks and to minimize antibiotic prescription [911]. However, some investigations have raised concern by suggesting that disinfectant overuse may induce mutations in microorganisms *Corresponding author: Lucilla Baldassarri, Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanità, Rome, Italy, Tel: +39.06.4990.2333; E-mail: [email protected]