Abstract:

Objective To analyze the drug resistance profile and related genes of Salmonella isolated from patients with acute infectious diarrhea in Shanghai,and to provide a reference for clinical diagnosis and treatment.Methods A total of 400 stool samples of patients with acute infectious diarrhea were collected for bacterial culturing. The suspected isolates and their serotypes were identified by Vitek MS. The susceptibilities of 15 commonly-used antibiotics against Salmonella were determined by minimum inhibitory concentration （MIC）,and the related genes were determined by polymerase chain reaction （PCR）.Results The dominant serotypes of 22 Salmonella isolates were Salmonella typhimurium （36.4%,8/22）,Salmonella enteritidis （27.3%,6/22） and Salmonella london （18.2%,4/22）. The 22 Salmonella isolates had the highest resistance rates to ampicillin/sulbactam （95.5%）,followed by ampicillin,levofloxacin,trimethoptim,sulfamethoxazole,ciprofloxacin-cefotaxime-gentamicin,cefazolin-cefuroxime-ceftazidime and amikacin. Piperacillin-tazobactam and imipenem had the susceptibility rate 100%. The positive rate of blaTEM-1 gene and blaDHA gene in beta-lactamase resistant isolates was 23.8% （5/21）. The positive rate of aadA1 gene in aminoglycoside resistant isolates was 25% （1/4）. The positive rates of qyrA4,qnrA,qnrB,qnrS and parC genes in quinolone resistant isolates were 47.1% （8/17）,5.9% （1/17）,11.7% （2/17）,17.6% （3/17） and 58.8% （10/17）. The positive rate of sulI gene in sulfonamide resistant isolates was 66.7% （4/6）.Conclusions The drug resistances of Salmonella are high and vary,and the related genes are different from the results of other domestic literatures,which indicates that the drug resistance mechanism of Salmonella is complex and the need to take individual and accurate diagnosis for personalized treatment.

Key words: Salmonella, Acute infectious diarrhea, Drug resistance profile, Drug resistance gene