WP7 Environmental Effects of Active Pharmaceutical Ingredients (APIs)
201 Oregon Ballroom
1:20 PM - 4:40 PM, Wednesday
() Assessing antibiotic resistance to enrofloxacin in aquatic systems using molecular techniques.
Graham, D1, Knapp, C1, Hawes, J2, Wellington, E2, 1 University of Kansas, Lawrence, KS, USA2 University of Warwick, Coventry, UK
ABSTRACT- The secondary effects of antibacterial agents, such as fluoroquinolone (FQ) antibiotics, have been of recent interest due to the increased resistance of pathogens to many antibacterials used in clinical settings. In order to study the impact of FQs on environmental microorganisms, a series of primers were designed that target the presumed resistance sequence in the gyrA gene (QRDR) that renders the protein non-susceptible to FQ binding. The prevalence of mutations in the QRDR region was tested in environmental samples with and without previous exposure to enrofloxacin, a common FQ used in agriculture. Although variation in the gyrA QRDR was noted in all samples, specific examination of exposed communities indicated that enrofloxacin selectively altered microbial community structure and the frequency of apparent QRDR sequences. To test the primers under quasi-real conditions, samples were collected from a series of aquatic mesocosms developed to study the fate of enrofloxacin in light-exposed, shaded, and dark water columns. Differences in light supply resulted in significantly different rates of disappearance of enrofloxacin, which resulted in different QRDR region patterns over time. Studies are ongoing to assess the significance of such variations among systems and on the prevalence of actual resistance.
Key words: enrofloxacin, aquatic systems, antibiotic resistance, molecular techniques