Drug resistance and molecular typing of Salmonella isolated from foodborne diseases in Ganzhou City

Abstract

ObjectiveTo provide scientific basis for rational clinical use and traceability of outbreaks of foodborne Salmonellosis， the drug resistance and molecular typing characteristics of foodborne Salmonella in Ganzhou City was understood， and a database of drug resistance and molecular fingerprinting of foodborne Salmonella in Ganzhou City was established.MethodsSerotyping， drug susceptibility testing， whole genome sequencing （WGS） and pulsed field gel electrophoresis （PFGE） were performed on 136 strains of Salmonella isolated from the active surveillance of foodborne diseases in Ganzhou City from 2020 to 2022. And drug resistance gene annotation and graphical clustering analysis were performed.ResultsThe highest rate of foodborne Salmonella in Ganzhou City was found for STR resistance （83.09%）， followed by TET （78.68%） and AMP （76.47%）. Multi-drug resistant strains accounted for 76.47%， with a wide range of resistance spectrum types， and the main prevalent resistance spectrum type was AMP-TET-CHL-STR-SXT. WGS predicted a total of 61 resistance genes in 7 categories， with the highest rate of aminoglycoside resistance genes （99.19%） and the lowest rate of macrolides （8.87%）. 136 strains of Salmonella with S. typhimurium variant and S. typhimurium as the dominant serotype were classified into 98 band types by PFGE molecular typing.ConclusionFoodborne Salmonella in Ganzhou City has a serious drug resistance status， with a high rate of drug resistance gene carriage and diverse genotypes. The PFGE molecular type is polymorphic. The dominant serotype may cause outbreaks and epidemics， and surveillance and research should be strengthened.

Keywords

• salmonella
• drug resistance
• whole genome sequencing
• drug resistance gene
• pulsed field gel electrophoresis
• serotyping
• foodborne diseases
• foodborne pathogenic