Zhongguo shipin weisheng zazhi (Feb 2023)

Study on multidrug resistance related genes of Salmonella isolated from food and clinical samples

  • ZHANG Mingyan,
  • GENG Yingzhi,
  • YU Miao,
  • ZHANG Meimei

DOI
https://doi.org/10.13590/j.cjfh.2023.02.006
Journal volume & issue
Vol. 35, no. 2
pp. 184 – 189

Abstract

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ObjectiveTo investigate distribution of integron and extended-spectrum β-lactamase produced by Salmonella isolated from food and clinical samples， and explore the relationship between different drug resistance genes and multidrug resistance.MethodsPhenotype of ESBL-producing strains were confirmed by K-B method. The ESBL related drug resistance genes （blaTEM， blaSHV， blaCTX） and the mobile element integron in Salmonella were amplified by polymerase chain reaction. The amplified products of integron variable region were sequenced and the drug resistance gene cassettes were analyzed.ResultsThree hundred and nine Salmonella strains were isolated. A total of 138 Salmonella strains were isolated from food， including poultry （n=96）， raw pork （n=19） and aquatic products （n=23）. One hundred and seventy one Salmonella strains were isolated from clinical samples. The drug resistance rate of 309 Salmonella strains was 78.3%， and the multidrug resistance rate was 41.1%. The antimicrobial resistance rate of poultry was the highest. A total of 56 ESBL-producing strains were detected， of which 35 strains carried the ESBL genes （15 strains carried blaTEM； 10 strains carried blaCTX， 10 strains carried blaTEM and blaCTX ）. The blaSHV gene was not detected. A total of 98 strains which carried class I integron gene were detected， and the positive rate was 31.7%. Among the 98 strains， 54 strains carried drug resistance gene cassette. Forty seven strains carried dfrA and aadA， 1 strain carried linG-aadA22， the rest were empty gene cassette. The multi-drug resistance rates of integron positive and ESBL-producing strains were as high as 98.0% and 89.3%， respectively. The positive rate of integron in ESBL-producing strains was 76.8% （43/56）.ConclusionThe class I integron and ESBL-producing Salmonella were widely distributed in this area. The genotypes of ESBL-producing strains were mainly blaTEM and blaCTX. Both integron and ESBL-producing strains were associated with multidrug resistance. The dug resistance situation of Salmonella in this area was serious， and it was particularly necessary to pay attention to the standardized use of antibiotics in poultry breeding.

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