Molecular typing, virulence genes and drug resistance of Salmonella typhimurium in Longyan city
10.3760/cma.j.issn.0254-5101.2019.11.001
- VernacularTitle: 龙岩市鼠伤寒沙门菌分子分型、毒力基因及耐药性测定
- Author:
Qianjin CHEN
1
,
2
;
Meihua LI
1
;
Chunyuan CAO
1
;
Linhong LIAO
1
;
Haibin CHEN
1
;
Xiaodong CHEN
1
Author Information
1. Department of Clinical Laboratory in Center for Disease Control and Prevention of Longyan City, Longyan 364000, China
2. Department of Clinical Laboratory, Teaching Base of Fujian Medical University in Center for Disease Control and Prevention of Longyan City, Longyan 364000, China
- Publication Type:Journal Article
- Keywords:
Salmonella typhimurium;
PFGE molecular typing;
Cluster analysis;
Minimum inhibitory concentration;
Multidrug resistance;
Virulence gene;
Salmonella virulence island;
Salmonella plasmid virulence gene
- From:Chinese Journal of Microbiology and Immunology
2019;39(11):805-811
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To analyze the molecular typing characteristics by pulsed field gel electrophoresis (PFGE), drug resistance and virulence genes of Salmonella typhimurium in Longyan city in order to provide reference for the prevention and control.
Methods:A total of 79 Salmonella typhimurium strains were isolated from sporadic cases of diarrhea and food poisoning and raw poultry meat samples during 2010 to 2017. PFGE was performed to measure the minimum inhibitory concentrations (MIC) of 15 commonly used drugs against them. PCR was used to detect nine virulence genes (sopB, invA, sifA, sscA, sseE, spvB, pefA, spvR, spvC) in 55 strains.
Results:The 79 Salmonella typhimurium strains belonged to 61 PFGE types. There were 10, three and four strains of P1, P3 and P21 types, respectively. Seven P1 type strains were isolate from one food poisoning event. According to the 85% classification standard, 79 Salmonella typhimurium strains could be divided into five predominant gene clusters (G1-G5). Drug susceptibility test showed that the 79 strains had the highest resistance rate to ampicillin (88.61%), followed by that to tetracycline (87.34%) and streptomycin (73.41%). Multidrug resistant bacteria resistant to three or more antibacterial drugs accounted for 84.81% (67/79). All of the 55 strains carried invA, sopB, sseE and sscA genes. The other five genes, sifA, spvC, spvB, spvR and pefA, were detected in 54, 31. 10, 11 and 12 strains, respectively. There were 76.4% (42/55) of the strains carrying five or six virulence genes and all were positive for invA, sopB, sseE, sscA and sifA, and negative for spvB, spvR and pefA. The strains carrying all of the nine virulence genes accounted for 18.2% (10/55).
Conclusions:Salmonella typhimurium strains isolated in Longyan city had a diverse PFGE type. P1, P3 and P21 types were the three predominant PFGE types. In the food poisoning event, PFGE molecular typing could quickly alert the outbreak and traceability of Salmonella typhimurium. Attention should be paid to the multidrug resistance in Salmonella typhimurium. Monitoring of multidrug-resistant strains and supervision on antibacterial drug usage should be strengthened. Salmonella typhimurium had high virulence as it carried many virulence genes.
