A few travel briefcases are shown in front of a cruise ship.
A particularly bad bug is hitching a ride back to the United States with travelers. Learn how to beat it and enjoy your vacation symptom free. (For Spectrum Health Beat)

International travelers are bringing a multidrug-resistant intestinal illness to the U.S. and spreading it to others.

Shigella sonnei is a bacteria that causes shigellosis, also known as traveler’s diarrhea or Montezuma’s revenge. It spreads easily from person to person when someone has the bug on their hands and touches their mouth or nose and through contaminated food and water.

Although Shigella causes about 500,000 cases of diarrhea in the U.S. every year, most cases clear up on their own.

For more severe cases, and for people with a suppressed immune system for whom shigellosis can be deadly, the antibiotic ciprofloxacin (Cipro) is considered the first-line treatment. The bug has already proven resistant to two other antibiotics: ampicillin and trimethoprim/sulfamethoxazole.

The concern, said the Centers for Disease Control and Prevention (CDC), is that the Shigella sonnei bacteria now appears resistant to Cipro and there aren’t many other ways to treat it.

“Drug-resistant infections are a real challenge to treat, plus Shigella is so quickly and easily spread. I know the CDC is concerned about larger outbreaks,” said Russell Lampen, DO, an infectious disease specialists with the Spectrum Health Medical Group. “Vulnerable groups include children in schools and daycare facilities and people who can’t easily practice good hygiene, such as the homeless.”

“Good hand hygiene is your best defense against shigellosis—washing your hands well with soap and water is important,” Dr. Lampen said. “International travelers can protect themselves further by choosing hot foods and drinking only from sealed containers.”

The CDC also recommends that travelers use over-the-counter medications, such as Pepto-Bismol or Immodium, to treat mild or moderate diarrhea, reserving antimicrobial medications for severe cases only, and seek medical care if they’re experiencing diarrhea upon return to the U.S. or if they develop it shortly thereafter.