Infection diagnosis and antibiotic susceptibility testing (AST) are pertinent clinical microbiology practices that are in dire need of improvement, as current standards are not able to keep up with the mutations and resistance development of certain bacterial strains. This paper presents a novel way to conduct AST which hybridizes disk diffusion AST with microwave resonators for rapid, contactless, non-invasive and high-throughput testing. This work uses Escherichia coli (E. coli) cultured on solid agar and places bacteria samples on a microwave split-ring resonator along with antibiotic disks (erythromycin) of various doses to demonstrate the viability of this sensing method in a clinical microbiological setting. The microwave resonator, operating at a 1.76 GHz resonant frequency, boasted a 5 mm2 sensitive sensing region. A one-port sensor was designed and optimized for detecting dielectric property variations of lossy dielectric materials accurately. This sensor was calibrated to detect uninhibited growth of the bacteria at 0.005 dB/hr, with a maximum change of 0.07 dB over the course of 15 hrs. The transient resonant amplitude change was subsequently dampened for each increasing dosage of antibiotic tested, with 45 µg of erythromycin showing negligible change indicating complete inhibited growth. This AST sensor demonstrated decisive results of antibiotic susceptibility in under 6 hours and shows great promise to further automate the intricate workflow of AST in clinical settings, while providing rapid, sensitive, non-invasive and high-throughput detection capabilities.