A PCR method of identification for Citrobacter freundii agglutinating with O157 serum

ObjectiveTo develop a PCR method to distinguish Citrobacter freundii which agglutinate with O157 serum from Escherichia coli O157. MethodsAll the strains isolated were subjects for biochemical identification, test for agglutination with O157 serum and test for wzx gene by PCR. ResultsThe wzx gene was detected in 25 strains of Citrobacter freundii which showed agglutination reaction with O157 serum，while no wzx gene was detected in 8 strains of Citrobacter freundii which showed no agglutination reaction with O157 serum. No wzxPCR product was detected in 20 strains of O157∶H7. ConclusionThe wzx-based PCR is a sensitive and rapid method to distinguish Citrobacter freundii strains which agglutinate with O157 serum from Escherichia coli O157 strains.