Multidrug-resistant shigellosis is now spreading throughout the United States, carried by tourists visiting other nations, and bringing the bacteria back home, according to the Centers for Disease Control and Prevention.
Between May 2014 and February 2015, at least 243 people in 32 states and Puerto Rico developed the illness. In nearly 90 percent of cases, the bacteria was found to be resistant to the first line of pharmaceutical defense against the disease, the antibiotic ciprofloxacin (Cipro).
"Drug-resistant infections are harder to treat and because Shigella spreads so easily between people, the potential for more — and larger — outbreaks is a real concern. We're moving quickly to implement a national strategy to curb antibiotic resistance because we can't take for granted that we'll always have the drugs we need to fight common infections," said Tom Frieden, director of the CDC.
Cipro is often prescribed to tourists traveling outside the Unites States as a precaution against developing diarrhea. The role this practice could play in strengthening antibiotic resistance among bacteria is still uncertain.
So far, 45 cases of shigella infections have been recorded in Massachusetts, 25 in California and 18 people in Pennsylvania, according to the CDC's PulseNet laboratory network. About half of the patients diagnosed with the infections had recently traveled internationally, including several who visited India or the Dominican Republic. Another 95 cases, mainly among homeless individuals or people living in hotels, were reported by the San Francisco Department of Public Health. None of those patients had recently traveled outside the United States.
Shigella sonnei can result in stomach cramps, diarrhea and fever. Physicians were already aware that the microorganisms are resistant to a pair of other antibiotics, ampicillin and trimethoprim/sulfamethoxazole.
Around half a million cases of diarrhea are caused by shigella in the United States each year. Most of these cases are resolved without the use of drugs. However, physicians often prescribe antibiotics, usually Cipro, in order to shorten the length of symptoms. While just 2 percent of bacteria in these patients is typically resistant to that drug, that number jumps to 90 percent among the newest cases.
Travelers visiting locations outside the United States can help avoid diarrhea by washing their hands regularly, only eating hot foods and drinking only from sealed containers, according to the CDC. The agency also recommends that mild cases of diarrhea should be treated with over-the-counter medicines, such as Pepto-Bismol, reserving antibiotics for the most severe infections.
Analysis of the most recent cases of shigella infections was detailed in the CDC's Morbidity and Mortality Weekly Report for April 3.
Photo: Leonid Mamchenkov | Flickr