China Animal Husbandry and Veterinary Medicine ›› 2021, Vol. 48 ›› Issue (9): 3464-3472.doi: 10.16431/j.cnki.1671-7236.2021.09.039

• Basic Veterinary Medicine • Previous Articles     Next Articles

Isolation,Identification and Drug Resistance Analysis of Klebsiella pneumoniae in a Large-scale Dairy Farm in Shihezi Area

WANG Zhehong1,2, WU Tongzhong2, ZHAO Yubin1, ZHANG Xingxing2, HAN Mengli2, ZHONG Fagang2, HU Jianjun1, HUANG Xin2   

  1. 1. College of Animal Science, Tarim University, Alar 843300, China;
    2. State Key Laboratory of Sheep Genetic Improvement and Healthy Breeding, Xinjiang Academy of Agricultural Reclamation Sciences, Shihezi 832000, China
  • Received:2021-02-25 Online:2021-09-20 Published:2021-09-17

Abstract: In order to clarify the main bacterial pathogens causing respiratory symptoms of calves in a large-scale dairy farm in Shihezi area and their biological characteristics, 39 nasal swabs and 39 anal swabs of 2-6 months old calves were collected. The biological characteristics of the isolated strains were analyzed by bacterial isolation and culture, morphological observation, biochemical analysis, PCR amplification of 16S rRNA and khe genes, drug sensitivity test and mouse pathogenicity test. The results showed that 3 of the isolated strains formed purplish red colonies with sedimentation rings on the MIAC plate (1 nasal swab and 2 anal swabs), and were Gram-negative Brevibacterium and suspected to be Klebsiella pneumoniae by microscopic examination. The automatic microbiological analysis system showed that the similarity between isolates and Klebsiella pneumoniae was 96%. PCR amplified 16S rRNA sequencing results showed that the nucleotide homology between the isolates and Klebsiella pneumoniae in the GenBank database was between 96.5% and 99.8%, and the specific gene khe of Klebsiella pneumoniae was positive and the similarity was over 99%. The results of drug sensitivity showed that the isolated strains were resistant to penicillins, cephalosporins, first-generation and second-generation aminoglycosides, tetracyclines, first-generation macrolides, sulfonamides, polyenes and lincamides. They were sensitive to the third generation of aminoglycosides, the second generation of macrolides, chloramphenicols, polypeptides and quinolones, and showed different degrees of multi-drug resistance. The pathogenicity test showed that the isolated strains could lead to the death of mice in varying degrees, and the nasal swab isolates were highly pathogenic. This study successfully isolated and identified three strains of Klebsiella pneumoniae causing respiratory symptoms of calves in large-scale dairy farms in Shihezi area, clarified some biological characteristics of the isolated bacteria, and provided technical support for detection, diagnosis and clinical treatment of bovine Klebsiella pneumoniae in Xinjiang.

Key words: Klebsiella pneumoniae; isolation; identification; pathogenicity; drug resistance

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