If the bacteria someone is infected with is antibiotic-resistant, doctors need to know as soon as possible. A simple new system could help by detecting such resistance in just 2 hours instead of the usual 24 hours he does.
Usually, to see if bacteria have developed resistance to a particular antibiotic, a population of bacteria is grown in Petri dishes and the drug is added. We can also perform genetic analysis of bacteria to see if they carry resistance-associated genes.
In either case, usually at least 24 hours for results. There are also some faster methods of “antibiotic susceptibility testing” (AST), but they require expensive and complex equipment. That’s where new technology comes in.
Developed by scientists at the EPFL Institute in Switzerland and the Free University of Brussels, the system utilizes a regular light microscope, special microscope slides and either a smartphone or digital camera.
The user begins by placing a drop of biofluid containing bacteria on the slide. Tiny microfluidic channels within the slide then draw the fluid into tiny cantilever-like structures. A cell phone or camera is then used to take a video of the bacteria on the structure through the microscope’s eyepiece.
Analyzing the video using specialized software allows the detection of small vibrations emitted by individual bacteria. According to scientists, these “nanomotions” are produced by all living organisms, not just all living microbes.
Needless to say, if you add antibiotics to the solution on the slide, the bacteria will should do it Die and stop vibrating. If they haven’t done so within two hours, the software indicates they are tolerant to that particular drug.
This system, known as optical nanomotion detection (ONMD), has already been used to accurately detect resistance. Escherichia coli, Staphylococcus aureus and Lactobacillus rhamnosus If exposed to bacteria, antibiotics ampicillin, streptomycin, doxycycline, vancomycin.
A paper on this research, led by Dr. Sandor Kasas of EPFL and Professor Ronnie Willaert of the Free University of Brussels, was recently published in a journal. PNAS.
Source: EPFL
