Characteristics of epidemiology and distribution of Salmonella Typhimurium worldwide based on NCBI database
Objective To analyze the prevalence and molecular characteristics of global Salmonella Typhimurium.Method The ge-nome and the corresponding serovars as well as meta-information of global Salmonella were downloaded in batch from the National Cen-ter for Biotechnology Information(NCBI)database using the online softwares,ResFinder,PlasmidFinder,Mobile Element Finder and MLST,to analyze the distribution of antibiotic resistant genes(ARGs),plasmids,mobile genetic elements(MGEs)and the sequence types(STs)among S.Typhimurium strains.Results A total of 101 ARGs were detected in 323 strains of S.Typhimurium,among which the most common was aac(6')-Iaa(322/323,99.69%),followed by sul2(155/323,47.99%),aph(3")-Ib(128/323,39.63%),aph(6)-Id(127/323,39.32%),tet(B)(109/323,33.75%),and blaTEM-1B(106/323,32.82%).Totally,36 plasmids were identified,among which IncFⅡ(S)(110/323,34.06%)and IncFⅠB(S)(108/323,33.44%)were the most common.Moreo-ver,376 MGEs were found,including 367 insertion sequences and nine transposons,among which MITEEc1(322/323,99.69%)and ISSen1(308/323,95.36%)were the most popular.Furthermore,323 strains of S.Typhimurium were assigned into 32 different STs,a-mong which,ST19(157/323,48.61%)and ST34(105/323,32.51%)were the most common accounting for over 82%.Among 115 strains of S.Typhimurium from human,18 STs were identified including ST19(52/115,45.22%)and ST34(39/115,33.91%)which were the most common.Conclusion S.Typhimurium carried multiple types of ARGs,in addition to the wide distribution of a large number of insertion sequences and plasmids,whch provide favorable conditions for the spread of drug resistance.Therefore,the meas-ures of prevention and control against the infection from this bacterium should be strengthened.
Salmonella Typhimuriumresistance geneplasmidsmobile genetic elementsequence type