Elle (19) is a Trinity College Dublin science student, Naughton Scholar and founder of Lablinn. She works to increase citizen access to science, blogs, and speaks at events around Europe. She has been named a Global Youth Leader in Nanotechnology, a T20 Young Global Changer and N.I. Young Scientist of the Year.
Antibiotic Resistance and Diagnostics
Why are Diagnostics important?
2. Treat and isolate antibiotic-resistant infections
The symptoms of a methicillin-resistant staph aureus (MRSA) infection may look similar to the symptoms of a normal staph aureus infection initially, but if you don’t realise that the infection is in fact MRSA you might give antibiotics that the bacterium is resistant to and the disease will continue to get worse. This can be fatal or life-altering – if you want to read more about these stories, check out Maryn McKenna’s Superbug, which is full of them.
Also, hospital staff may want to put patients infected with resistant infections into isolation to avoid giving anyone else a disease that’s so hard to treat – the sooner they know what the infection is, the sooner they can make that decision.
Developments in ABR Diagnostics
There are various challenges and prizes for people to develop new tests that can quickly and cheaply tell apart bacterial and viral infections, or tell resistant bacteria from susceptible ones, like these from the NIH in America or the European Union.
Current diagnostic tests for bacterial infections are generally done by culturing the bacteria i.e. letting them grow for a day or so and seeing what they look like and if any grew in areas where antibiotics had been put. This takes a few days, which doesn’t work well with the timescale of a GP consultation.
Some new technologies in development that can help are RNA sensors, a 30 minute test that measures how well bacteria can replicate their DNA (something antibiotics target) using DNA markers, a 10 to 30 minute test that works by studying individual bacterial cells, and a test involving viruses called bacteriophages that have been modified by immobilizing antibodies, DNA or dyes onto them and move when they bind to the target bacteria, a change that can be detected by measuring the amount of light that passes through the sample and takes about one minute.
Some tests focus on the specific mechanism of resistance the bacterial strain uses, e.g. some bacteria target beta-lactam antibiotics (antibiotics that contain a particular ring shape in their chemical structure, e.g. penicillins, cephalosporins, carbapenems) using the enzyme beta-lactamase to hydrolyse the beta-lactam ring, breaking the ring open and rendering the antibiotic non-functional. The test detects the enzyme to see if the bacteria is resistant to that class of antibiotics.
With the advent of next-generation DNA sequencing allowing many more samples to be tested in a short period of time than before, the possibility of sequencing the DNA of the bacteria is getting closer to reality as costs go down. This could be helpful because resistant bacteria carry resistance genes that code for resistance enzymes like the beta-lactamase mentioned above or staphylococcal cassette chromosome mec in MRSA. These genetic elements can be particularly important because bacteria can and do exchange DNA, including resistance genes.
These examples are all recent – there are many more, and it will likely take some time before they become cheap, simple and popular enough to make their way into the clinic on a large scale.
For Diagnostics Weekend at Lablinn, we’re going to be focusing on nanodiagnostics and doing a feature on APOPO’s HeroRATs and how they detect tuberculosis.