A team of researchers has invented a multidimensional antimicrobial susceptibility testing (AST) system which can provide information about drug resistant pathogens present in patients.
The technology, developed by researchers from the Department of Chemistry at Hong Kong Baptist University (HKBU), is said to be a world first and can enable doctors to accurately determine the effectiveness and appropriate dosage of antibiotics needed for effective treatment.
The team is planning to commercialise the system that is said to be 10-20 times faster, more accurate and can be run at a much lower cost than current AST methods which are only available in professional medical laboratories. The invention is aimed to aid diagnosis by providing doctors with a precise prescription that will reduce the change of antibiotic abuse or misuse.
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 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.
Dr Ren Kangning, assistant professor in the Department of Chemistry at HKBU, who led the research team, 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. Doctors will first evaluate the patient and then analyse a small amount of their body fluid using the new system. Based on the results, the antibiotic (or a combination thereof) with the lowest susceptibility, the best efficacy, and the most appropriate dosage will be selected for the patient. Hence, we can achieve better therapeutic performance and slow down the process of antibiotic resistance.”
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. This means that current treatment can be time-consuming and can stimulate antimicrobial resistance.
As the new system employs microfluidic technology, Dr Ren explained that compared with the existing AST methods, it requires much smaller samples and takes significantly less time to carry out tests. In addition, the synergistic effects of multiple drugs and the dynamic changes of different substances in the human body can also be simulated. The ability to automate the test can reduce possible errors from human manipulation and observation too.
The research findings have been published in the international academic journals Lab on a Chip, ChemPlusChem, and Trends in Biotechnology
