Fluoroquinolone resistance: mechanisms, impact on bacteria, and role in evolutionary success  Liam S. Redgrave, Sam B. Sutton, Mark A. Webber, Laura J.V. Piddock  Trends in Microbiology  Volume 22, Issue 8, Pages 438-445 (August 2014) DOI: 10.1016/j.tim.2014.04.007 Copyright © 2014 Elsevier Ltd Terms and Conditions

Figure 1 Correlation between fluoroquinolone (FQ) usage and resistance rates in countries with high, medium, and low use of FQs. Percentage of FQ-resistant Escherichia coli isolates (bars) and FQ consumption in defined daily dose (DDD) per 1000 patients per day (lines) in Greece, France, and Sweden. Greece, France, and Sweden are high, moderate, and low users of FQs respectively (relative to other European countries) and this correlates with high, moderate, and low rates of resistance in E. coli. Data from http://www.ecdc.europa.eu/en/healthtopics/antimicrobial_resistance/database/Pages/database.aspx. Trends in Microbiology 2014 22, 438-445DOI: (10.1016/j.tim.2014.04.007) Copyright © 2014 Elsevier Ltd Terms and Conditions

Figure 2 Action of type II topoisomerases on DNA. The control of supercoiling by type II topoisomerases in bacteria. Supercoiling is a measure of how over- or under-wound the double helix is and is required for packaging of the bacterial chromosome within the cell and to relieve the torsional stress resulting from DNA replication. DNA gyrase introduces negative supercoils into DNA; bacterial chromosomes favour a negatively supercoiled state. Topoisomerase IV positively supercoils DNA, can also introduce negative supercoils, and has a role in separating the interlinked daughter chromosomes (themselves usually supercoiled) resulting from replication of the chromosome. Trends in Microbiology 2014 22, 438-445DOI: (10.1016/j.tim.2014.04.007) Copyright © 2014 Elsevier Ltd Terms and Conditions