China Animal Husbandry and Veterinary Medicine ›› 2021, Vol. 48 ›› Issue (11): 4292-4301.doi: 10.16431/j.cnki.1671-7236.2021.11.039

• Basic Veterinary Medicine • Previous Articles     Next Articles

Establishment of the Epidemiological Cut-off Values of Haemophilus parasuis for Quinolones

CHEN Jiali, CHEN Chaoqun, WU Xue, HUANG Anxiong, HAO Haihong   

  1. National Reference Laboratory of Veterinary Drug Residues (HZAU), National Laboratory for Safety Evaluation of Veterinary Drugs (Wuhan), Laboratory of Quality & Safety Risk Assessment for Livestock and Poultry Products of Ministry of Agriculture and Rural Affairs (Wuhan), Wuhan 430070, China
  • Received:2021-04-06 Online:2021-11-20 Published:2021-11-01

Abstract: In order to better understand the current situation of drug resistance of Haemophilus parasuis (Hps) to quinolones and establish the epidemiological cut-off values (ECOFFs) of Hps to quinolones, this test was done according to the method specified in the CLSI-VET. By searching from databases such as ScienceDirect, PubMed, CNKI and others, the MICs of 605 strains of ciprofloxacin, 74 strains of ofloxacin, 322 strains of levofloxacin, 211 strains of danofloxacin, 276 strains of nalidixic acid, 143 strains of lomefloxacin, 638 strains of enrofloxacin and 262 strains of mabofloxacin were collected and corrected. Then the statistical software ECOFFinder was used to fit the data, draw the nonlinear regression of MIC distribution and determine the ECOFFs and drug resistance rates of Hps to 8 quinolones. Among the 8 drugs, the drugs that could only be used for veterinary clinical use were danofloxacin, enrofloxacin, marbofloxacin and ciprofloxacin. As the first generation quinolone antibacterial, nalidixic acid had been withdrawn from the market. And the other three drugs should not be used in the veterinary clinic. The result of the experiment was that the ECOFFs of Hps to ofloxacin, nalidixic acid, lomefloxacin, levofloxacin, ciprofloxacin, danofloxacin, marbofloxacin and enrofloxacin were 8, 4, 4, 0.25, 0.25, 0.625, 0.625 and 0.03125 μg/mL, respectively. It showed that wild type strains of Hps had high sensitivity to ciprofloxacin, danofloxacin, marbofloxacin and enrofloxacin which were available in veterinary clinic and it's recommended to use them in veterinary clinical use. However, the drug resistance rate of these four drugs was also high, indicating that the existence of drug-resistant strains was serious. The data concluded in this paper was applicable in the era of frequent international exchanges and could be used as the criterion of sensitivity and resistance when there was no corresponding pharmacodynamics and clinical breaking point at home and abroad. And it also laid a foundation for further establishing clinical breaking point, guiding clinical medication and prolonging the clinical service life of quinolones.

Key words: Haemophilus parasuis (Hps); quinolones; ECOFFs; drug resistance; resistance mechanisms

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