Drug-resistant Shigella sonnei infections in the United States have been linked with international travelers who repeatedly transmit the bacterium domestically, leading to an increasing proportion of US shigellosis cases that are resistant to the first-line antibiotic treatment, ciprofloxacin.
Recent outbreaks of ciprofloxacin-resistant shigellosis sickened 243 people in 32 states and Puerto Rico between May 2014 and February 2015. About half of the infections were associated with international travel, mostly to the Dominican Republic and India. Ninety-five of the cases were in San Francisco, where a ciprofloxacin-resistant shigellosis outbreak was linked with the homeless population or people living in single-room occupancy hotels.
Increasing Ciprofloxacin Resistance Among US Shigellosis Outbreaks. JAMA. 2015;313(20):2016. doi:10.1001/jama.2015.4988