Serological analysis and pulsed-field gel electrophoresis typing on Salmonella isolated from patients with diarrhea in Nanshan district of Shenzhen, Guangdong, 2010-2013

Objective To understand the serological characteristics of Salmonella circulating in diarrhea patients in Nanshan district of Shenzhen, Guangdong province. Methods A total of 1868 stool samples were collected from local diarrhea patients from 2010 to 2013 to condcut Salmonella isolation, identification, serotyping and related pulsed-field gel electrophoresis. Results A total of 92 Salmonella strains were isolated, the isolation rate was 4.93%. The isolation rate was highest in age group 4-10 years (23.21%), followed by age group 1-3 years (8.26%). There was no significant difference in isolation rate between age groups1 year (1.45%) and age group11 years (5.41%). There was no sex and year specific significant differences in isolation rate. The Salmonella strains were in 19 serogroups. S. Typhimurium was the major serogroup, accounting for 38.04%, followed by S. Enteritidis, accounting for 31.52%, and S. Stanley, accounting for 7.61%. Forty-one PFGE patterns were detected in 61 strains, at least 7 strains were in one PFGE pattern. S. Typhimurium strains had 17 PFGE patterns, T1 was the major pattern. E1 was the major PFGE pattern of S. Enteritidis strains. Two household clustering of Salmonella infection were detected, one was S. Rissen infection in a twins, and another one was S. Enteritidithe infection in a couple and their mother. Conclusion The Salmonella isolation rate was highest in age group 4-10 years, it is necessary to take measures to improve the lifestyle and health status of this group. S. Typhimurium and S. Enteritidis were the major serogroups circulating in this area. Timely PFGE typing can play a important role in the prevention and control of infectious diseases.