16srRNA sequences of ivermectin and moxidectin challenged bacterial isolates

Due to their broad-spectrum activities, ivermectin and moxidectin are widely used anthelminthics in veterinary and human medicine. However, ivermectin has recently been shown to perturbate gut-microbial growth. Given the macrolide-like structure of both ivermectin and moxidectin, there is a need to characterize the antibiotic spectrum of these anthelminthic drugs and their potential implications in the development of cross-resistance to macrolides and other families of antibiotics. In the course of our study, we challenged 5 bacterial isolates with repeated and gradually increasing concentrations of these two anthelminthics and subsequently characterized their sensitivity to different antibiotics as well as ascending anthelminthic concentrations. For each isolate we sequenced the full-length 16SrRNA region prior to and after anthelminthic challenging with either ivermectin or moxidectin. The final challenging concentration for both ivermectin or moxidectin was 20uM.