Epidemiological characteristics and fingerprinting polymorphism of Salmonella in human, Heilongjiang

Objective  To understand the serotypes and molecular characteristics of Salmonella in human in Heilongjiang province. Methods  Serotyping and pulsed-field gel electrophoresis (PFGE) polymorphism analysis on Salmonella isolated from diarrhea cases were carried out in Heilongjiang from 2016 to 2019. Results  A total of 303 strains of human Salmonella were detected in 9 977 cases of diarrhea patients during this period. The detection rates of Salmonella were higher in Daqing, Harbin and Qiqihar, and the annual detection rate was higher in the second quarter than in other quarters. The detection rates of Salmonella in age groups 16–20 years and 56–60 years were higher than those in other age groups. Salmonella in Heilongjiang had 46 serotypes. The proportion of S. enteritidis, the main serotype causing human infection, was as high as 40.59%. There were 67 different PFGE patterns of S. enteritidis, which can be divided into three band clusters. 54.10% of the predominant strains were from infants under 5 years old. Conclusion  People aged 16–20 years and 56–60 years were at high risk for human Salmonella infection, and S. enteritidis was the main serotype causing human infection. The fingerprints of human Salmonella in Heilongjiang showed polymorphism distribution.