A rapid and quantitative absorption-based measurement to study the impact of antibiotics on bacterial growth

Given the global rise in antimicrobial resistance levels, an urgent need exists to obtain the Minimal Inhibitory Concentration (MIC) of an antibiotic as early as possible. In this paper we present the first test results of a light-based concept where the interaction of a laser beam with the drug-bacterium sample is used for calculating MIC values within 6 hours after cultivation. For this preliminary study, a total of 163 drug-bacterium pairs were tested and benchmarked with broth microdilution (BMD). The pathogen set included Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii, Staphylococcus aureus, Staphylococcus capitis, Staphylococcus cohnii, Staphylococcus epidermis, Staphylococcus haemolyticus, Enterococcus and Streptococcus pneumoniae. The selected drugs belonged to 10 different classes. The method under investigation showed a categorical concordance of 86.1% and an essential agreement of 80.3% with BMD. Due to its simplicity, the concept can be easily implemented on existing commercial platforms. This research shows a promise for further studies potentially leading to a novel concept that can be employed to rapidly determine MIC values.