 A new drug-resistant 'superbug' is circulating the country, and health officials say it was brought in from overseas. The Associated Press says Shigella has already triggered more than 200 illnesses since last May, and experts worry that the bacteria might be here to stay. People who recently traveled to the Dominican Republic, India or a handful of other developing countries, say health authorities, appear to be bringing Shigella back to the U.S. And they're spreading the highly-contagious disease in various pockets across many states. Though outbreaks of Shigella are considered common, this particular strain is resistant to a common antibiotic known as azithromycin. According to the National Institutes of Health (NIH), azithromycin is typically used in children to treat bacterial infections like bronchitis, pneumonia and certain sexually transmitted diseases (STDs). As of this writing, at least 243 people from multiple states have come down with the disease, which is a common cause of diarrhea. The largest outbreaks have been reported in Massachusetts, Pennsylvania and California. 'This is the first time we've documented this large an outbreak of antibiotic-resistant (shigella) linked to international travel,' stated Dr. Anna Bowen from the Centers for Disease Control and Prevention (CDC) about the growing outbreak. 'It's moving itself around the country,' but it's too early to know if the superbug has rooted in the United States for good, added Bowen. New Shigella strain resistant to both azithromycin (for children) and ciprofloxacin (for adults) Shigella spreads easily through contaminated food, as well as pools and ponds. Outbreaks often occur at daycare centers when staff members fail to properly wash and sanitize their hands after changing babies' diapers. Infection typically goes away within a week, and conventional symptom remedies include products like Pepto-Bismol and Imodium. But this latest circulating strain doesn't respond to certain antibiotics -- besides azithromycin, Shigella is also resistant to ciprofloxacin, or Cipro, the azithromycin counterpart for adults. 'This particular strain is resistant to ciprofloxacin -- something that has been relatively rare in Shigella -- which makes this particularly concerning, and something we need to watch carefully over the coming days and weeks,' said Brian Coombes, a researcher at the Michael G. DeGroote Institute for Infectious Disease Research (IIDR) at McMaster University. Drug-resistant Shigella cases spreading throughout North America Cipro, it turns out, is one of Western medicine's primary treatment protocols for infections of all kinds. With this common antibiotic now out of the conventional mix, it remains to be seen how the medical-industrial complex will approach this latest deadly superbug . Its importation from other countries is also concerning, especially after it was revealed last year that thousands of illegal immigrant children from Central America were being shipped into the U.S. and distributed throughout the country. 'Outbreaks of this nature are a threat because of the ease of international travel,' added Coombes. 'The infectious dose of Shigella is very low so the potential for larger outbreaks is a real concern.' In Canada, health officials are now reporting that 14 percent of the 663 infectious cases of Shigella recorded between 2010 and 2015 are resistant to ciprofloxacin. And the total number of Shigella cases has been steadily increasing in Canada over the past several years, especially in Ontario. 'That means that one-quarter of the people you treat with that antibiotic may not get better,' stated Dr. Vanessa Allen, chief of medical microbiology for Public Health Ontario, to The Canadian Press, noting that in some cases this percentage is as high as 24 percent. 