Low-cost High-throughput Method for Determining Electron-Beam Irradiation Doses for Antibiotic Degradation

Abstract

In recent years, there's been growing interest in using Electron Beam Irradiation (EBI) to break down medical waste and help control the spread of antimicrobial resistance. The amount of EBI required to degrade antibiotics varies depending on whether they are in a free aqueous form or bound to another material. There is no standard method to identify the exact dose required to degrade each antibiotic; hence, to determine the precise dose needed for antibiotics in both water and cellulose-bound states, a high-throughput technique has been optimised using a sterile 96-well plate.  Different concentrations of Chloramphenicol (CAP) and Oxy-Tetracycline (OT) in their aqueous form were exposed to EBI. The degradation was assessed using a simple well diffusion assay. Similarly, 40 antibiotics impregnated in a cellulose matrix, were exposed to EBI, with degradation measured through a disc diffusion method. EBI-exposed 96-well plates containing different concentrations of antibiotics showed degradation, as indicated by a reduced zone of inhibition. Similarly, cellulose-bound antibiotics exposed to EBI also exhibited a decreased zone of inhibition. It concludes that 1. Cost Optimization: Electron beam treatment is expensive, but diluting antibiotic solutions reduces the required dose and overall operating cost, 2. Form Effect: Antibiotics bound to cellulose need higher doses; extracting them into an aqueous form lowers the dose and processing cost. 3. Simple Testing: No special equipment, such as LC-MS are not required, using a simple agar well or disc diffusion tests can effectively determine the required degradation dose.