Drug resistance analysis and molecular typing of Escherichia coli from animal source in Changsha City

Zhou Rushun; Yang Jiahao; Jiang Yan; Chen Qiyou; Liu Shuguang; Zhang Jianchao; Long Xueming

doi:10.20154/j.cnki.issn1672-9692.2025.01.014

Abstract：The aim of this study was to investigate the resistance of animal-derived bacteria to common antibiotics in Changsha City of Hunan Province.The drug resistance,drug resistance genes,virulence genes and genetic relationships of animal-derived Escherichia coli isolated from Changsha City in 2023 were studied.The results showed that 407 biological samples were collected from 36 farms and 332 strains of Escherichia coli were isolated,the isolation rate was 81.57%.The resistance to ampicillin was the most serious,and the resistance rate was 64.95%.The drug resistance rates of tetracycline and trimethoprim/sulfamethoxazole were 64.05%and 63.44%,respectively.The rate of drug resistance to other antibiotics was below 40%.Among the Escherichia coli from different sources,the resistance of Escherichia coli from swine was the most serious,followed by that from poultry,and the resistance of Escherichia coli from cattle was relatively light.The detection rate of multidrug-resistant bacteria in isolates was 58.43%.The detection rates of drug resistance genes and virulence genes were high,among which tetracycline resistance genes tet(A)had the highest detection rate(84.62%),and some virulence genes such as csgA and hlyE had 100.00%detection rate.Phylogenetic tree results showed that Escherichia coli isolated from different farms in Changsha City were related to each other to some extent,which proved that there might be bacterial transmission or migration.The study showed that the drug resistance of Escherichia coli of animal origin in Changsha City was serious,and there was a certain level of transmission,suggesting that the drug resistance monitoring should be maintained and the use of antibiotics should be standardized in farms.