Acta Veterinaria et Zootechnica Sinica ›› 2023, Vol. 54 ›› Issue (12): 5184-5197.doi: 10.11843/j.issn.0366-6964.2023.12.028

• PREVENTIVE VETERINARY MEDICINE • Previous Articles     Next Articles

Distribution and Genotyping of Major Enterobacteriaceae Bacteria in Milk Sources and Dairy Farm Environment of Hainan Province

HAO Ruochen1,2, TANG Minjia2, LIU Guangliang1,3, ZHANG Yan1, MUHAMMAD Shoaib2, SHANG Ruofeng2, CAO Zongxi1*, PU Wanxia2*   

  1. 1. Hainan Provincial Key Laboratory of Tropical Animal Breeding and Disease Research, Institute of Animal Science and Veterinary Medicine, Hainan Academy of Agricultural Sciences, Haikou 571100, China;
    2. Gansu Province Key Laboratory of New Animal Drug Project, Ministry of Agriculture and Rural Affairs Key Laboratory of Veterinary Drug Discovery/Lanzhou Institute of Husbandry and Pharmaceutical Sciences of CAAS, Lanzhou 730050, China;
    3. Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730046, China
  • Received:2023-02-23 Online:2023-12-23 Published:2023-12-26

Abstract: In this study, major bacteria in Enterobacteriaceae were isolated from 52 samples collected from two dairy farms in Hainan Province in 2021. The virulence genes detection, plasmid type, biofilm-forming ability and enterobacterial repetitive intergenic consensus (ERIC) molecular typing of isolates were studied in order to clarify the distribution, prevalence and biological characteristics of the isolates in Enterobacteriaceae in milk and dairy farm environment. First, the isolates in Enterobacteriaceae were identified by 16S rDNA PCR. The results showed that 49 strains of Enterobacteriaceae were isolated from 52 samples, including 32 strains of Escherichia coli, 13 strains of Klebsiella pneumoniae, 3 strains of Enterobacter cloacae and 1 strain of Enterobacter aerogenes. The results of virulence gene testing showed that ompA had the highest detection rate. Plasid typing is performed by PCR-based replicon typing created by CARATTOLI. The results showed that the detection rate of K plasmid was the highest among 49 isolated bacteria. The biofilm-formating ability of isolates was qualitatively detected using the Congo Red Agar method. Thirty-seven isolates were positive. The genetic relationship and diversity of Enterobacteriaceae were determined by ERIC-PCR. The results showed that 49 strains of Enterobacteriaceae were divided into 17 types (I-XVI), and the dominant type was type VI (all Escherichia coli), with a total of 20 strains. The overall study showed that Enterobacteriaceae widely existed in the milk and environment, causing a high risk of human and animal diseases. It is suggested that hygiene and standardized operation in breeding and transportation are crucial.

Key words: Enterobacteriaceae, molecular typing, plasmid type, biofilm

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