title: Genetic basis of aminoglycoside resistance following changes in aminoglycoside prescription patterns.
abstract: Aminoglycosides (AG) offer an important therapeutic option for the treatment of infections caused by multiresistant Enterobacteriaceae. We observed a change in AG usage patterns in our institution between 1997 and 2006, namely a reduction in use of all AG except amikacin. We studied the changes in AG susceptibility rates in these time periods and correlated with prevalence of different molecular resistance mechanisms. Enterobacteriaceae isolated from blood cultures from 1997 and 2006 were studied. Susceptibilities to AG were determined with the disk diffusion method. PCR was used to detect genes encoding AG-modifying enzymes and methylases. Gentamicin resistance rates dropped from 14·5 to 8·8%, whereas resistance rates to other AG remained unchanged. The AAC(6')-I+AAC(3)-I combination was more common in 1997, whereas AAC(6')-I was the most common mechanism in 2006. Reduction in gentamicin use may preserve the usefulness of this agent against severe infections by multiresistant bacteria such as carbapenemase-producing Enterobacteriaceae.
authors.affiliation: Infectious Diseases and Antimicrobial Chemotherapy Research Laboratory, First Department of Propaedeutic Medicine, University of Athens, Greece. ckosmidis@gmail.com
authors.forename: Chris
authors.initials: C
authors.lastname: Kosmidis
authors.forename: Maria
authors.initials: M
authors.lastname: Giannopoulou
authors.forename: Anastasia
authors.initials: A
authors.lastname: Flountzi
authors.forename: Antonis
authors.initials: A
authors.lastname: Markogiannakis
authors.forename: Dimitris
authors.initials: D
authors.lastname: Goukos
authors.forename: George
authors.initials: G
authors.lastname: Petrikkos
authors.forename: George L
authors.initials: GL
authors.lastname: Daikos
authors.forename: Konstantina
authors.initials: K
authors.lastname: Tzanetou
mesh_terms: D000583:Amikacin / Q000494:pharmacology; D000617:Aminoglycosides / Q000494:pharmacology*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D018432:Drug Resistance, Multiple / Q000235:genetics*; D004363:Drug Utilization; D004755:Enterobacteriaceae / Q000187:drug effects / Q000235:genetics*; D004756:Enterobacteriaceae Infections / Q000188:drug therapy* / Q000453:epidemiology / Q000235:genetics; D005838:Genotype; D005839:Gentamicins / Q000494:pharmacology; D006115:Greece / Q000453:epidemiology; D006801:Humans; D008826:Microbial Sensitivity Tests; D010818:Practice Patterns, Physicians'
chemical_list: D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D005839:Gentamicins; D000583:Amikacin