Rapid antibiotic resistance testing

Researchers from the Department of Chemistry at Hong Kong Baptist University (HKBU) led by Dr Ren Kangning have invented the world's first multidimensional antimicrobial susceptibility testing (AST) system. The new technology can provide information about drug resistant pathogens present in patients, enabling doctors to accurately determine the effectiveness and appropriate dosage of antibiotics needed for effective treatment.

HKBU Research - Rapid antibiotic resistance testingDr Ren Kangning

Test results known in four hours

In order to accurately test and analyse antibiotic resistance, the team fabricated a hydrogel microfluidic chip which simulates the drug diffusion process and the killing of pathogenic bacteria inside the human body. The system is simple to operate and only requires a small amount of the patient's body fluid, such as blood or saliva. Once unwanted substances have been removed, the sample fluid is placed on the chip, and is then treated with different antibiotics.

After about four hours, the system indicates the effectiveness of the antibiotic treatment and whether it is needed. Due to the chip's multidimensional properties, multiple variables can be introduced simultaneously, such as different antibiotics, nutrients and immunologic substances. Automated microscopic observation of bacterial growth also enables users to determine the most appropriate type, or the best combination, of different types of antibiotics and the required dosage for treatment.

HKBU Research - Rapid antibiotic resistance testingHydrogel microfluidic chips

More accurate and lower cost

The new fully-automated system is 10-20 times faster, more accurate and can also be run at a much lower cost than the current AST methods which are only available in professional medical laboratories. It is expected that the invention will aid diagnosis by providing doctors with a precise prescription which will significantly reduce the chance of antibiotic abuse or misuse.

Dr Ren said that currently clinical doctors assess a patient's suspected bacterial infections according to his/her experience. They then decide whether to prescribe antibiotics, tailoring the treatment and type of antibiotic to be applied accordingly. If the patient does not recover having taken the medicine, the doctor will reassess or use another antibiotic. Currently there are ASTs available for doctors to assess the patients' antimicrobial susceptibility but it takes a few days to obtain the results.

As a result, the current treatment process is not only time-consuming and inefficient, but can also stimulate antimicrobial resistance due to misuse or overuse of antibiotics. Moreover, doctors usually prescribe broad-spectrum antibiotics to speed-up treatment times and target a wide-range of different bacteria. This broad-spectrum approach can also kill harmless bacteria, accelerating antibiotic resistance in pathogens and affecting the long-term health of patients.

Dr Ren said: "Our new method can analyse bacterial morphology and quantity under the microscope. It takes only four hours to obtain accurate AST data, and with this new method the treatment process can be faster and more accurate."