Increase in Resistance of Methicillin-Resistant Staphylococcus aureus to β-Lactams Caused by Mutations Conferring Resistance to Benzalkonium Chloride, a Disinfectant Widely Used in Hospitals
Abstract
Increase in Resistance of Methicillin-Resistant Staphylococcus aureus to β-Lactams Caused by Mutations Conferring Resistance to Benzalkonium Chloride, a Disinfectant Widely Used in Hospitals Nobuyoshi Akimitsu , Hiroshi Hamamoto , and Ryu-ichi Inoue Mikio Shoji and Akifumi Akamine Koh-ichi Takemori and Naotaka Hamasaki Kazuhisa Sekimizu * Department of Molecular Microbiology Graduate School of Pharmaceutical Sciences Kyushu University Fukuoka, Japan Department of Operative Dentistry and Endodontology Faculty of Dentistry Kyushu University Fukuoka, Japan Central Clinical Laboratory Kyushu University Hospital Fukuoka, Japan Laboratory of Developmental Biochemistry Graduate School of Pharmaceutical Sciences University of Tokyo 7-3-1, Hongo, Bunkyo-ku Tokyo, Japan Methicillin-resistant Staphylococcus aureus (MRSA) has been found worldwide and is one of the major nosocomial agents. When MRSA strains were first discovered in hospitals, resistance of MRSA to low concentrations of β-lactams was evident, but increasing resistance to high concentrations of β-lactams is now common. Most of the key elements responsible for methicillin resistance of MRSA have been well defined; however, mechanisms related to the acquisition of those genetic phenotypes in hospitals remain uncertain ( 4 ). Appearance of MRSA resistant to benzalkonium chloride, a disinfectant widely used in hospitals, has been reported ( 1 ). To determine if the disinfectant might