Abstract:Objective To investigate the majority molecular typing characteristics of Cronobacter contamination in powdered infant formula (PIF), analyze the genetic correlation of strains from different provinces, and provide technical support to track diseases of Cronobacter infection in China. Methods Pulsed field gel electrophoresis(PFGE)and multilocus sequence typing(MLST)were used to analysis 49 strains isolated from PIF from 19 provinces in China. Results Totally 49 strains of Cronobacter were divided into 38 clusters, no obvious dominant cluster and aggregation were found. There were 15 ST types and 2 new ST types in 49 strains, ST4, ST1 and ST64 were the dominant types, accounted for 20.4% (10/49), 18.4% (9/49), 10.2% (5/49), respectively. The result of PFGE and MLST showed that strains with the same PFGE type also had the same MLST type, however, the same MLST type was not necessarily related. Conclusion Cronobacter isolated from PIF in China showed highly polymorphism and discreteness, it could predict that the infant infected by Cronobacter contamination in PIF in China was mainly sporadic, the incidence of outbreak of multiple people was low.