In 2016, 554 culture-confirmed cases of shigellosis (10.1 per 100,000 population) were reported. This represents a 190% increase from the 292 cases reported in 2015, and is 300% greater than the median annual number of cases reported during 2006-2015 (median, 185.5 per year; range, 66 to 391). S. sonnei accounted for 512 (92%) cases, and S. flexneri for 38 (7%) cases. The species was not identified in 3 (1%) cases. There was 1 S. dysenteriae infection reported in 2016. Cases ranged in age from 11 months to 87 years (median, 11.5 years). Twenty-eight percent of cases were ≤5 years of age; 46% of cases were 18 years of age or older. Fifty-eight percent of cases were female. Ninety-eight (18%) cases were hospitalized. No cases died.
Forty-three percent of cases reported either non-white race (201 of 538 cases) or Hispanic ethnicity (69 of 526 cases). Of the 513 cases for which travel information was available, 20 (4%) travelled internationally (14 of 477 [3%] S. sonnei, and 6 of 33 [18%] S. flexneri). Fifty-three percent of cases resided in the metropolitan area, including 26% in Hennepin County and 12% in Ramsey County.
One hundred eight (19%) cases were part of 30 Shigella outbreaks identified in 2016 (median, 2 laboratory-confirmed cases per outbreak; range 1 to 29). All 30 outbreaks were due to person-toperson transmission of S. sonnei: 24 outbreaks were in child care facilities, five outbreaks were in schools or preschools, and one outbreak was in a shelter.
In 2016, 133 patients were positive for Shigella by a culture-independent diagnostic test conducted in a clinical laboratory. Ninety-three (72%) of the 129 specimens that were received at MDH were subsequently culture-confirmed and therefore met the surveillance case definition for inclusion in MDH case count totals.
In 2016, 50 of the 544 Shigella isolates received at MDH were tested for antimicrobial resistance. Of the 50 isolates, 46% (23 isolates) were susceptible to trimethoprimsulfamethoxazole, 98% (49 isolates) were susceptible to ampicillin, and 100% were susceptible to azithromycin.
- For up to date information see>> Shigellosis (Shigella)
- Full issue>> Annual Summary of Communicable Diseases Reported to the Minnesota Department of Health, 2016