Practical disk-based method for detection of Escherichia coli clinical isolates producing the fluoroquinolone-modifying enzyme AAC(6')-Ib-cr.

摘要

Since a fluoroquinolone-modifying enzyme gene, aac(6')-Ib-cr, was first reported in 2006, it has rapidly spread among Enterobacteriaceae clinical isolates worldwide (7). AAC(6')-Ib-cr differs from AAC(6')-Ib by two amino acids, Trp102Arg and Asp179Tyr, and these substitutions allow it to reduce the antibacterial activities of norfloxacin and ciprofloxacin through acetylation of their piperazinyl substituent (6). Detection of aac(6')-Ib-cr has so far depended mainly on genotyping, PCR, and sequencing (2). Recently, simultaneous high-resolution melting analysis and pyrosequencing were developed for detection (1, 3). However, these methods are costly and need specialized equipment. Therefore, the availability is limited to highly advanced institutions, such as research laboratories and university hospitals. In the present study, we developed a cost-effective and practical disk-based method to screen for AAC(6')-Ib-cr producers.