Researchers at Caltech have developed a new rapid test for antibiotic-resistant bacteria, which can give results within 30 minutes.
Antibiotics are becoming less effective with the rise of multi-drug resistant strains of bacteria. At present, a doctor doesn’t know if their patient is infected with a drug-resistant strain without sending a sample to a lab, and it can take as long as three days to get the results back.
This means that most antibiotic treatments are a shot in the dark. A new test, developed by Caltech researchers, could help change this. The research team aimed to develop a simple test that could be completed during a short visit to a doctor’s surgery.
The researchers focused on urinary tract infections (UTIs), which are very common, and developed a rapid test that works on the following principle. A doctor would divide a urine sample from a patient with a UTI into two parts, and expose one part to an antibiotic for 15 minutes, while not treating the other part.
The bacteria in each sample are then broken apart and their cellular contents are analyzed through a chemical detection process called digital real-time loop-mediated isothermal amplification. This technique amplifies specific DNA markers on a chip, allowing doctors to visualize them in the samples, where they appear as fluorescent spots.
The idea is that the bacteria exposed to the antibiotic will undergo less DNA replication and therefore will produce fewer DNA markers. However, if they are resistant to the antibiotic, their DNA replication will not be affected and the test will show similar DNA markers for both the treated and untreated bacteria.
The team tested their chip on urine samples from patients with UTIs. The test was 95% consistent with the results from a gold-standard laboratory test for antibacterial resistance, showing that it is likely accurate enough for routine use in doctors’ offices. In the future, the team plans to expand the scope of the test for other bacteria and other bodily fluids, such as blood.
Study in Science Translational Medicine: Rapid pathogen-specific phenotypic antibiotic susceptibility testing using digital LAMP quantification in clinical samples…