Laboratory analysis on a Shigellosis outbreak based on PulseNet China

ObjectiveTo conduct a laboratory analysis on a Shigellosis outbreaks in Tongzhou district of Beijing in September, 2019 based on PulseNet China.

MethodsIsolation and identification of the Shigellosis outbreak strains were conducted in Tongzhou district of Beijing in 2019, pulsed field gel electrophoresis（PFGE） molecular typing and drug resistance test were carried out and compared based on the Shigella strains isolated from surveillance and outbreaks in Tongzhou during 2015–2019.

ResultsAmong the 28 Shigella strains, the similarity of the band patterns of 27 strains was ≥92.0%, and the similarity of the band patterns of outbreak related strains was ≥97.1%, indicating the existence of a group of closely related Shigella strains in this area with limited circulation. All the strains were multi-drug resistant. Compared with the Shigella sonnei isolates from 2015 to 2018, the difference in resistance to gentamicin of the isolates in 2019 was significant（χ²=49.907, P<0.001）, suggesting that gentamicin should be used with caution in the treatment of Shigellosis. All the strains were sensitive to ciprofloxacin, chloramphenicol, cefoxitin and imipenem, suggesting that these antibiotics have good therapeutic effects on Shigella infection.

ConclusionIn recent years, Shigella sonnei is the main pathogen of dysentery in Tongzhou, the strains share high homology and have severe multi-drug resistance. Therefore, it is necessary to make use of national network surveillance system for pathogen identification to strengthen the routine and drug resistance surveillance for Shigella.