Jay M. Lieberman, medical director of infectious diseases for Quest Diagnostics, which serves approximately half the physicians and hospitals in the U.S., says that the wide adoption of the new tests means that public health officials will need to come up with new ways to monitor and respond to new outbreaks. For example, health officials will need to work with the labs to figure out how to get an isolate or find another way to characterize pathogens.
"By connecting cases, we can find problems in the food supply we might not have found," says John Besser, deputy chief of the CDC's Enteric Diseases Laboratory Branch. "The challenge for us is to develop a test that will provide all the information that we need without going to the isolate step. That's a significant challenge, but we all believe it's doable."
At present, no one is working on developing a test that can help public health officials trace outbreaks, though several companies continue to develop the new nonculture tests, including Abbott Laboratories, BD, Cepheid and Luminex. Besser says he expects laboratories to quickly adopt them when they become available. For the labs, the new tests mean quicker, cheaper results requiring fewer highly trained staff.
Although the problem of tracking pathogens related to foodborne illness is new, similar concerns were raised when nonculture tests were developed for detecting the sexually transmitted disease gonorrhea.
"When it comes to gonorrhea, almost all testing is done by nonculture techniques now," explains Quest's Lieberman. In response to that sea change, the CDC set up a surveillance project that allows it to monitor trends in a new way. At specified labs in 28 cities across the U.S., cultures are run and isolates taken from samples collected from the first 25 men found to have urethral gonorrhea each month. With that limited data set, public health officials can still track outbreaks while also allowing for broader use of the new nonculture tests.
Although that procedure has worked well for gonorrhea, whether it will also work for foodborne illnesses remains an open question.
An irony of all of this, says the CDC's Besser, is that the new tests for foodborne pathogens may be better than the old ones, but if they disrupt the public health systems, they "could result in a lot more people getting sick. That is the unintended consequence."