Open AccessAnalysis of the mutant selection window and killing of Mycoplasma hyopneumoniae for doxycycline, tylosin, danofloxacin, tiamulin, and valnemulin
Author(s) -
Zibin Huang,
Chunxiao Mao,
Yongxiang Wei,
Xiaoyan Gu,
Quan-Ying Cai,
Xin Shen,
Huanzhong Ding
Publication year - 2020
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0220350
Subject(s) - mycoplasma hyopneumoniae , tiamulin , tylosin , danofloxacin , microbiology and biotechnology , agar dilution , broth microdilution , minimum inhibitory concentration , biology , antibiotics , enrofloxacin , ciprofloxacin
Mycoplasma hyopneumoniae is the major pathogenic microorganism causing enzootic pneumonia in pigs. With increasing resistance of M . hyopneumoniae to conventional antibiotics, treatment is becoming complicated. Herein, we investigated the mutant selection window (MSW) of doxycycline, tylosin, danofloxacin, tiamulin, and valnemulin for treating the M . hyopneumoniae type strain (ATCC 25934) to determine the likelihood of promoting resistance with continued use of these antibiotics. Minimum inhibitory concentration (MIC) values against M . hyopneumoniae were determined for each antimicrobial agent based on microdilution broth and agar dilution methods (bacterial numbers ranged from 10 5 colony-forming units (CFU)/mL to 10 9 CFU/mL). The minimal concentration inhibiting colony formation by 99% (MIC 99 ) and the mutant prevention concentration (MPC) were determined by the agar dilution method with three inoculum sizes. Antimicrobial killing was determined based on MIC 99 and MPC values for all five agents. MIC values ranged from 0.001 to 0.25 μg/mL based on the microdilution broth method, and from 0.008 to 1.0 μg/mL based on the agar dilution method. MPC values ranged from 0.0016 to 10.24 μg/mL. MPC/MIC 99 values were ordered tylosin > doxycycline > danofloxacin > tiamulin > valnemulin. MPC achieved better bactericidal action than MIC 99 . Based on pharmacodynamic analyses, danofloxacin, tylosin, and doxycycline are more likely to select resistant mutants than tiamulin and valnemulin.