The TEM-1, NDM-1, CAT-I, aadB, and aac(6′)-Im antibiotic resistance genes were individually placed under control of the IPTG-inducible tac promoter on pSKunk1, a minor variant of plasmid pSKunk3 (AddGene plasmid #61531) (Firnberg and Ostermeier 2012 ). The CAT-I gene was amplified from pKD3 (AddGene plasmid #45604). An A to C mutation was made at base pair 219 within the CAT-I gene using the QuickChange Lightning Site-Directed Mutagenesis kit (Agilent) to match the native E. coli CAT-I sequence. The NDM-1, aadB, and aac(6′)-Im genes were ordered as gene fragments with adapters from Twist Bioscience. We verified the correct size and antibiotic resistance gene sequence for each plasmid using agarose electrophoresis gels and Sanger sequencing, respectively before transforming the resulting plasmids into electrocompetent NEB 5-alpha LacIq cells, which contain an F” episome encoding LacI. We produced these electrocompetent cells starting from a single tube of NEB 5-alpha LacIq chemically competent cells. Chemically competent cells were plated on LB-agar containing 10 μg/ml tetracycline to ensure the presence of the F” episome. A single colony was selected to produce electrocompetent cells with aliquots of the resulting electrocompetent cells used for all experiments within this study. All growth experiments were conducted in LB media supplemented with glucose (2% w/v) and spectinomycin (50 µg/ml) to maintain the pSKunk1 plasmid except where otherwise noted. Expression of the antibiotic resistance proteins was induced by the addition of 1 mM IPTG to exponentially growing cultures.