China Animal Husbandry and Veterinary Medicine ›› 2022, Vol. 49 ›› Issue (8): 3212-3225.doi: 10.16431/j.cnki.1671-7236.2022.08.037

• Basic Veterinary Medicine • Previous Articles     Next Articles

Isolation and Identification of Actinobacillus pleuropneumoniae from Guangdong Province and Detection and Analysis of Drug Resistance Phenotype and Gene

XU Minsheng1,2, KE Haiyi1,2, SHI Keda1,2, YANG Dongxia2, ZHAI Shaolun2, ZANG Yingan1, LI Chunling2   

  1. 1. College of Animal Science and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou 510305, China;
    2. Guangdong Scientific Observation and Experiment Station of Veterinary Drugs and Diagnostic Technology, Ministry of Agriculture and Rural Affairs, Guangdong Key Laboratory of Animal Disease Control and Research, Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China
  • Received:2022-03-14 Online:2022-08-05 Published:2022-07-21

Abstract: 【Objective】 This study was aimed to investigate the drug resistance phenotype and drug resistance gene carrying status of Acinetobacter pleuropneumoniae (APP),a pathogen of porcine contagious pleuropneumia (PCP) in some large-scale pig farms in Guangdong province,and to analyze and compare their correlation,so as to provide theoretical basis for effective prevention and control of PCP.【Method】 The dead pig materials of suspected PCP collected from large-scale pig farms in different regions of Guangdong province from 2019 to 2021 were isolated,identified and sequenced by pathogen isolation and culture,Gram staining,biochemical test,PCR amplification and other methods.Then the drug sensitivity test was carried out on the isolated strains,and their drug resistance genes were detected by PCR to determine their drug resistance phenotype and the carrying rate of drug resistance genes,and the consistency between them was analyzed and compared.【Result】 The isolates needed to be grown in culture plates containing serum and NAD.Gram staining results showed that the isolated bacteria were red,which could be determined as Gram-negative bacteria.Through biochemical test,PCR results and sequencing analysis,20 strains of APP were isolated,and did not show obvious regional characteristics.All strains showed multiple drug resistance,and about 50% of the strains showed 8 or more drug resistance.The drug resistance rates to tetracyclines,sulfonamides,chloramphenicols and macrolides were 77.5%,65.0%,55.0% and 48.8%,respectively.Further analysis showed that the isolated bacteria were mainly resistant to tetracycline,sulfaisoxazole,florfenicol and lincomycin,but sensitive to cefazolin (Pioneer V) and azithromycin.blaCMY, aph(2″)-Ⅰb,sul1,sul2,sul3,tetA,tetB,tetM,tetO,tetR and floR were detected in 23 main drug resistance genes,and the carrying rates were 85%,85%,50%,60%,75%,30%,100%,85%,100%,70% and 80%,respectively.No quinolones,macrolides and lincomycin related resistance genes were detected.【Conclusion】 APP isolated from pigs in Guangdong province showed extensive drug resistance and multiple drug resistance.The drug resistance gene was basically consistent with the drug resistance phenotype,indicating that the carrying of drug resistance gene was one of the main reasons for bacterial resistance to antibiotics,but there might also be other undetected drug resistance genes or new drug resistance mechanisms.

Key words: porcine contagious pleuropneumia; Actinobacillus pleuropneumoniae (APP); isolation and identification; drug resistance phenotype; drug resistance genes

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