Detecting levels of antibiotics in blood paves the way to individualized treatment

A new methodology for rapidly measuring the level of antibiotic drug molecules in human blood serum has been developed, paving the way to applications within drug development and personalised medicine. The study, published today in  Nature Nanotechnology , describes the exploitation of a sensor for measuring the concentration of effective antibiotics in blood, giving an indication of their efficiency against disease causing pathogens, for instance multidrug resistant hospital "superbugs". This development could potentially give a far greater understanding of the effectiveness of drug dosages required for different individuals, reducing potential toxic effects, allowing personalised treatment for patients and leading to new insights into optimal clinical regimes, such as combination therapies. When effective, antibiotic molecules impose cellular stress on a pathogen's cell wall target, such as a bacterium, which contributes to its breakdown. However, competing molecules in solution, for example serum proteins, can affect the binding of the antibiotic to the bacterium, reducing the efficacy of the drug. Serum proteins bind to drugs in blood and, in doing so, reduce the amount of a drug present and its penetration into cell tissues. As the amount of antibiotics that bind to serum proteins will vary between individuals, it is extremely valuable to be able to determine the precise amount of the drug that is bound to serum proteins, and how much is free in the blood, in order to be able to accurately calculate the optimum dosage.