With foodborne illnesses on the rise, it should be considered a win that testing for the responsible bacterias is getting faster. But, according to an announcement from the Centers for Disease Control, there's a significant cost for that speed. The culture-independent diagnostic tests, which are gaining popularity because of their quick results, "do not provide the information needed to characterize the organisms that cause infections."
CIDTs work by detecting the presence of a specific antigen or genetic sequence of a germ, according to the CDC. They don't require labs to grow a culture for isolation and identification of living organisms, which allows for the speedy test results. But with no culturing, CIDTs don't provide an isolate for the organism that causes illness. That means the tests don't provide information on whether an organism is a particularly virulent strain, how likely it is to respond to antibiotics, and if it's been found in other people who are sick, suggesting an outbreak.
The CDC is looking into faster tests for bacteria that also provide more in-depth information about the organisms, and it's developing "fingerprinting" techniques that do not depend on having an isolate. But as Gizmodo notes, it's unlikely a breakthrough will come in the short term.
In the meantime, outbreaks caused by salmonella, E. coli, listeria, and more seem to be popping up with increasing regularity. The CDC is taking other actions in an attempt to identify and curb these public health disasters. Among its chief strategies, the government agency is encouraging laboratories to perform reflex culturing, which takes a closer look at specimens with positive CIDT results for intestinal bacteria. This doesn't offer the desired combination of speed and thoroughness, but it does take a step toward better identifying what strains of bacteria might be responsible for widespread illnesses.