Why it may be worth identifying what caused your food poisoning

You’re at the doctor with a severe case of food poisoning. Should you ask for tests to find out which microbe caused it?

“Testing lets you identify specific pathogens where treatment may be of benefit,” says Glenn Morris, director of the Emerging Pathogens Institute at the University of Florida.

“There are certain pathogens you want to treat with antibiotics and others you definitely don’t,” explains Morris. “Two that you don’t want to treat are E. coli O157:H7 and Salmonella.”

Treating E. coli O157:H7 with antibiotics—or with anti-diarrhea drugs like Imodium—can make you sicker.

“And treating Salmonella with antibiotics can prolong the time that you’re a carrier,” says Morris. A carrier may have no symptoms but can still infect others. (Antibiotics may make sense, however, if you have a weak immune system or if the doctor suspects that the Salmonella has entered your bloodstream.)

More reasons to test

What’s more, testing for pathogens is faster and less expensive these days.

“It used to be that when a patient went to a doctor or a clinic with diarrhea that was likely caused by food poisoning, a stool culture could be ordered to try to identify the pathogen that was responsible,” says Morris.

But it was no slam dunk. If the lab didn’t pick the right medium for growing the bacteria, it wouldn’t find the culprit.

“Consequently, we always knew that we were significantly under-diagnosing foodborne illness,” says Morris.

Rather than trying to grow the bacteria, labs are using tests that look for telltale DNA to identify bacteria and viruses.

“The big hospitals have all pretty well switched over to DNA identification,” says Morris. “They use commercial kits that can identify a laundry list of 15 to 25 pathogens from a single stool sample. So all of a sudden we can identify pathogens that we couldn’t routinely identify in the past.”

That has made it harder to know if food poisoning strikes less or more often than it used to.

“We can’t tell whether there’s been a real increase or if it’s just that we can see more with new technology,” says Morris. “Regardless, foodborne illness is still an ongoing problem that hasn’t gone away.”