Acta Veterinaria et Zootechnica Sinica ›› 2022, Vol. 53 ›› Issue (11): 4027-4034.doi: 10.11843/j.issn.0366-6964.2022.11.028

• BASIC VETERINARY MEDICINE • Previous Articles     Next Articles

Epidemiological Characteristics of ESBL-Producing Resistant Bacteria in Dairy Farming Environment

ZUO Yang1, LI Tian1, HU Xiuhua1, SONG Zhiqiang2, SUN Chengtao1, WU Congming1, WANG Shaolin1*   

  1. 1. College of Veterinary Medicine, China Agricultural University, Beijing 100193, China;
    2. Inner Mongolia Yili Industrial Group Co. LTD, Huhhot 010080, China
  • Received:2022-04-11 Online:2022-11-23 Published:2022-11-25

Abstract: The purpose of this study was to explore the epidemiological characteristics of ESBL-producing resistant bacteria in the dairy farming environments. A total of 160 samples were collected from 6 farms in Inner Mongolia and Ningxia from 2020 to 2021, including milk, milk area skin swabs and environmental sources. β-lactamase rapid test strip, with the isolation and identification, drug sensitivity, and genome sequencing of ESBL-producing resistant bacteria, were conducted respectively. The positive rate of β-lactamase in all farms was 75%-100% in 24 milk samples. A total of 6 ESBL-producing resistant strains were isolated from 153 samples in 5 farms, and these ESBL-producing resistant strains had high resistance rates to amoxicillin (100%), cefotaxime (91.0%) and ceftazidime (78.2%). And 14 ESBL-producing Escherichia coli strains sequenced were found to carry multiple drug resistance gene types, with blaCTX-M (100%) carrying rate being the highest. At the same time, the sixth special farm with "long-term positive lactamase test" was found that ESBL-producing Acinetobacter baumannii was the main strain of β-lactamase positive in the milk of the farm, and the resistant strain carried blaCTX-M, blaTEM and blaOXA β-lactamase resistance genes. This study identified the epidemiological characteristics of ESBL-producing resistant bacteria in farm environments in Inner Mongolia and Ningxia, and the causes of lactamase positivity in the milk of one farm in Inner Mongolia were successfully traced back.

Key words: ESBL-producing resistant bacteria, dairy farming environment, bovine mastitis, epidemiological characteristics, β-lactamase

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