[Molecular typing of Salmonella paratyphi A isolates from four provinces with pulse-field gel electrophoresis].

Objective: To analyze the molecular types of Salmonella paratyphi A strains isolated in the recent years, and to construct the standard S. paratyphi A databank in the laboratory surveillance network PulseNet China.
Methods: S. paratyphi A isolates from 4 provinces were analyzed with the standard pulsed-field gel electrophoresis (PFGE) protocol used in PulseNet and their patterns compared. The databank was constructed with BioNumerics.
Results: Eleven PFGE patterns were obtained, in which 3 predominant patterns were identifies with a similarity coefficient of 96.3%. The strains of these patterns, accounted for 86.5% of the analyzed strains, appeared in different provinces and years.
Conclusion: The databank of S. paratyphi A was constructed and could be used in laboratory surveillance of S. paratyphi A in PulseNet China. From the analyses on molecular typing of the isolates, data suggested that the predominant strains might cause the epidemics in different regions.