[Pathogenic detection and molecular tracing of a bacillary dysentery outbreak by Shigella sonnei in Huainan city].

Objective: To understand the virulence gene and drug resistance profile of Shigella sonnei outbreak in Huainan city, and conduct pathogenic traceability analysis. Methods: Water samples and feces related to an infectious diarrhea outbreak in Huainan city in August 2020 were collected for multiple pathogen detection. Virulence gene, drug sensitivity, pulse-field gel electrophoresis and whole genome sequencing of Shigella isolates were analyzed respectively. Results: 38 strains of Shigella sonnei were detected in 56 samples of mucilage feces with a positive rate 67.86%, and all serotypes were Shigella sonnei Phase I. Three strains of Shigella sonnei were detected by fluorescence PCR in the Gram-negative (GN) bacterial enrichment solution of terminal water and well water. Virulence genes were ipaH positive (38), ipaH/ial (31) and ipaH/ial/sen positive (1), respectively. The drug resistance spectrum showed that 9 of 14 antibiotics were 100% resistant, and only imipenem, chloramphenicol, ceftazidime and ciprofloxacin were effective drugs. XbaⅠ restriction enzyme map type of 36 isolates was completely consistent, and the ST type analysis of 3 strains was ST152. Whole genome sequencing and analysis verified that the outbreak was caused by a single clonal group of strains, and revealed that the isolates of the outbreak were clustered into a large cluster with 3 Chinese strains and 1 Korean strain in the database, far away from the strains of other countries. Conclusion: The outbreak is caused by a single clone of Shigella sonnei, which are low virulence strains and have multiple drug resistance.

Emergence of Autochthonous Melioidosis in Two Inland PLADs - China, 2021.

What is already known about this topic?: Melioidosis, a tropical infectious disease caused by Burkholderia pseudomallei (BP) infection, is endemic in the southern coastal provincial-level administrative divisions (PLADs) of China. What is added by this report?: Three melioidosis cases, including two in young children and one in a 19-year-old female, were reported in Anhui and Jiangxi (two inland PLADs of China) respectively, in 2021. None of the patients had a travel history to a melioidosis-endemic area. All the BP isolates belonged to the same sequence type (ST51), which had been reported from elsewhere in Southeast Asia. What are the implications for public health practice?: This is the first report of autochthonous melioidosis cases in inland Chinese PLADs. Surveillance and prevention and control work should be strengthened in this region.