Shigella sonnei has spread via international travelers to 32 states and Puerto Rico, US health officials say.
Between May 2014 and February 2015, a drug-resistant strain of shigella has infected 243 people across the US, according to the US Centers for Disease Control and Prevention (CDC). The CDC’s findings were first published in the agency’s Morbidity and Mortality Weekly Report.
The CDC found that 90 percent of cases of the shigellosis infection analyzed in Massachusetts, California, and Pennsylvania were resistant to ciprofloxacin (Cipro), the top shigellosis antibiotic in the US.
The agency found that the potent, Cipro-resistant strain was “repeatedly introduced as ill travelers returned and was then infecting other people in a series of outbreaks around the country.” Many shigella strains in the US were already considered too advanced for other drugs, including ampicillin and trimethoprim/sulfamethoxazole.
The CDC added that shigellosis spreads quickly among nursing homes, “childcare facilities, homeless people and gay and bisexual men, as occurred in these outbreaks.”
“These outbreaks show a troubling trend in Shigella infections in the United States,” said CDC Director Tom Frieden in a public statement.
The CDC was first alerted to the new breed of shigella – which causes diarrhea in those infected – in December. Further investigation found that the strain was resistant to Cipro. The agency found that international travelers were largely responsible for the strain’s introduction, while other cases, including around 100 infections among the homeless population in San Francisco, were contracted by other means.