Abstract: In order to study the drug resistant phenotype and genotype of Escherichia coli (E. coli) in waterfowl, a total of 1 505 duck feces, water and soil samples were collected from waterfowl farms and their surrounding environment in Guangdong, Fujian, Zhejiang, Jiangsu and Shandong provinces of China. E. coli were isolated by selective medium and identified by MALDI-TOF-MS mass spectrometry.Drug resistance phenotypes were detected by minimal broth dilution method, and the 25 drug resistant genes in E.coli were screened by PCR.The results showed that a total of 449 strains of E.coli were isolated and identified from 1 505 samples, the separation rate was 29.8% and 335 were from feces, 52 were from soil and 62 were from water, among these samples, Zhejiang (43.3%) and Guangdong (43.2%) were the highest, followed by Fujian (28.1%) and Jiangsu (23.8%), and Shandong (18.3%) had the lowest separation rate.449 strains of E.coli were multiple drug resistance.The resistance rates to ampicillin, ciprofloxacin, aureomycin, florfenicol and sulfonamides were 90.2%, 50.3%, 96.7%, 87.3% and 90.6%, respectively, while they were sensitive to tegacyclin and meropenem.E.coli from different provinces showed different resistance rates to different antibiotics.The PCR results showed that in 449 strains of E.coli, the detection rate of resistance gene tet(A) was the highest (88.2%).It was followed by floR (58.13%), sul2 (57.02%), tet(B)(53.9%), cmlA (39.2%) and sul1 (36.75%), the positive E.coli of qnrA, tet(M) and tet(X) were not detected.Among the 5 provinces, the distribution of all drug resistance genes was high in the samples of Shandong province, but low in the samples of Zhejiang and Jiangsu provinces.In conclusion, this study investigated the drug resistance status of E.coli in waterfowl and surrounding environment of 5 coastal provinces in Southeast China, providing a theoretical basis for the standard use of antibiotics in aquaculture.

Key words: waterfowl; Escherichia coli; resistance; resistant genes