The treatment of infections can be challenging, as it takes some time to determine if harmful bacteria are even present, and to then figure out which antibiotic would work best. A simple new test, however, is said to answer both questions on the spot.
Ordinarily, a patient's blood or urine samples have to be sent off to a lab for analysis. It typically takes a few days for the results to get back – in the meantime, the doctor may administer a broad-spectrum antibiotic. Such medications aren't as effective as those that target the specific bacteria that's causing the infection, plus their overuse contributes to the development of antibiotic-resistant bacteria.
With these drawbacks in mind, a team at Britain's University of Southampton developed the inexpensive new single-use device.
It consists of three laser-cut layers: a top one that contains four commonly-used antibiotics in four small rectangular areas, a middle one made of absorbent paper, and a bottom one consisting of an agar bacteria-culturing gel. Everything is sealed within a plastic case.
Users start by applying a patient's biofluid sample to the device's paper inlet tab, which is then covered with tape to keep it from drying out or becoming contaminated. The fluid proceeds to soak through the paper, contacting all four of the antibiotic rectangles.
If any harmful bacteria are present in the sample, the paper will turn blue. That said, there will be a clear non-blue spot around any of the rectangles that contain an antibiotic which is effective against that type of bacteria. If the paper is blue but there are no clear spots, then it means another antibiotic is required.
When the device was used to analyze artificial urine that had been spiked with E. coli bacteria, it was found to be as reliable as traditional lab tests performed in petri dishes.
"By enabling doctors to quickly determine if an infection is caused by bacteria, and if the bacteria are resistant to four common antibiotics, this device could cut down on unnecessary antibiotic prescriptions and help fight the growing threat of antibiotic resistance," says the lead scientist, Dr. Collin Sones.
A paper on the research was recently published in the journal Biosensors and Bioelectronics.
Source: University of Southampton
