New Method To Determine Antibiotic Resistance Fast

Scientists have developed a new method of rapidly identifying which bacteria are causing an infection and determining whether they are resistant or sensitive to antibiotics. The findings are now being published in the Journal of Clinical Microbiology.
 
Antibiotic resistance is a growing medical problem that threatens human health all over the world. Today, many people are dying because of infections caused by resistant bacteria. When an infected person is treated with antibiotics, 'empirical therapy' is usually provided. This means that the choice of antibiotic is based on the resistance situation of the bacteria in a large population, rather than on the resistance, if any, of the bacteria in the infected person's body. The result is sometimes selection of an antibiotic drug that is ineffective against the bacteria concerned, because the latter is resistant to the drug chosen. This, in turn, boosts the use of antibiotics, especially what are known as 'broad-spectrum' antibiotics that work on many types of bacteria. One possible solution to these problems would be for us to have reliable methods of quickly and easily identifying the bacterial species causing the infection and its resistance pattern, and apply the correct treatment immediately.
 
This is just what the researchers have been doing. They have developed a new method that permits identification of both the species and the resistance pattern of bacteria in urinary infections in less than four hours. By comparison, the resistance determination done at present takes one to two days.
 
The method is based on highly sensitive, bacterium-specific measurement of bacterial growth in the absence and presence of various antibiotics. If the bacterium is resistant, it can multiply with antibiotic present; this is detected as a rise in the number of copies of a specific DNA sequence. If it is sensitive, on the other hand, no growth takes place. The researchers showed that the method could identify correctly both the bacteria and their resistance patterns in all the clinical samples analysed.
 
The method is highly specific and sensitive, and can be automated for use in a clinical laboratory. What is more, it is entirely general in application and could, in principle, be used for all types of bacteria and antibiotics.
 
An instrument based on the method is currently being developed, which focuses on blood infections. Such infections are life-threatening and it is extremely important for effective treatment that the patient should start taking the correct antibiotic without delay. A working instrument is expected to launch on the market in 2017.