•Activity of fosfomycin against ESBL-producing Escherichia coli from urine samples was evaluated.•Prevalence and underlying mechanism of fosfomycin resistance were determined.•The location of fosA3 on a plasmid was determined.

Objective:To establish a method to detect serotype of foodborne Salmonella typhimurium with a multiplex polymerase chain reaction (PCR)assay.Methods:Randomly select four strains which isola-ted from food (i.e.,No.84,No.95,No.99 and No.06),and re-sequenced their genomic sequences of Flagel-lum I phase encoding genes (fliC)and Flagellum II phase encoding genes (fljB)with regard to the amplified sequences using a multiplex PCR assay.Each serotype of Salmonella typhimurium was identified by blasting. Results:The serum model of four strains (84,95,99,06)were1,4:z4,12:e,h:1,2,1,4,12:i:1,2,6,8:z4, z23:e,n,z15 and 8,20:i:z6,and the serotypes of which were S.Saintpaul,S.Typhimurium,S.Chailey respec-tively,but serotype of 06 can not be determined.In addition,several novel genetic variants were observed in these strains.Conclusion:The multiplex PCR assay can be used to assess the serotype of foodborne Salmo-nella typhimurium,which has some practical value.

Objective To trace the virus source and control blows by SARS virus genotyping. Methods The sequences of SARS-Cov and SARS-like virus from GenBank were download. Taking the bovine coronavirus, the avian infectious bronchitis virus and the breda virus as the outgroup, SARS virus and SARS-like virus system evolution tree was constructed,and the single nucleotide variation was investigated systematically. Results The viruses from two SARS nature epidemics may obviously be divided into two different clusters. SARS virus from humanity in secondary epidemic and SARS-like virus from animals such as himalayan palm civet were divided into H and P genotypes for the first time. The H/P genotyping mainly based on virus’s genome sequence rather than the spike gene sequence. Conclusion The viruses of two SARS nature epidemics possibly infect the humanity by different characteristis,and the secondary epidemic was not a simple repetition of the first one.Source-tracing analysis of SARS virus for the secondary epidemic was adopted on molecular level.No clear relations of the gene sequences between the first two index patients’ viruses and SARS-like viruses from animals were found.Some new views about SARS-CoV’s prototype and the relation between SARS virus and bat’s coronavirus were proposed.