Analysis of Drug Resistance and Molecular Typing of Humanized Salmonella Enteritidis in Linyi from 2022 to 2023
Objective:To understand the drug resistance and molecular typing characteristics of Salmonella enteritis in diarrhea cases monitored in Linyi city from 2022 to 2023,and provide reference for monitoring and preventing Salmonella infection.Method:Whole genome sequencing and drug sensitivity testing were performed on 31 strains of Salmonella enteritidis from Linyi city,to analyze the multi site sequence typing(MLST),resistance genes,and antibiotic resistance phenotype of the isolated strains.Using NZ-CP018657 as the reference genome,CSI Phylogeny 1.4 was used to identify single nucleotide polymorphism(SNP)sites in the genomes of 44 Salmonella enteritis strains(including 13 common database genomes),and a phylogenetic tree based on SNP was constructed to analyze the phylogenetic relationships between strains.Result:29 strains of Salmonella enteritis were identified as ST11 type,and the corresponding ST types were not found in the database for the other 2 strains.31 strains of Salmonella enteritis isolated in Linyi are all antibiotic multidrug-resistant bacteria,with resistance rates to various antibiotics ranging from 3.23%to 100.00%.Among them,ampicillin and Ampicillin sulbactam have the highest resistance rates(100.00%),and no strains resistant to meropenem,ertapenem or amikacin were found.25 isolated strains are resistant to 3～5 out of 14 antibiotics,divided into 14 drug resistance spectrums.Based on whole genome sequencing data,a total of 8 categories and 15 resistance genes were predicted,with aminoglycoside resistance genes(54.11%)being the most common,and the aac(6')-Iaa carrying rate was 100%.A phylogenetic tree was constructed based on 23 821 SNP sites identified from 44 strains of Salmonella enteritis.The results showed that 31 Linyi isolates were divided into 3 branches,of which 25 isolates clustered to one branch with close genetic relationships.Conclusion:From 2022 to 2023,multiple drug resistance of Salmonella enteritidis was severe in Linyi city.Molecular typing results indicate there are obvious dominant strains of Salmonella enteritidis in our city.It is recommended that relevant departments strengthen monitoring based on local Salmonella enteritidis resistance and molecular typing characteristics,and provide effective warnings for the source,transmission,and infection of this serotype.
NETL
NSTL
万方数据
