@article{MAKHILLJAVA201211133555,
    title = {Role of Mutations in DNA Gyrase and Topoisomerase IV in Fluoroquinolones-Resistance 
  of<I> Mycoplasma gallisepticum </I>Obtained <I>in vitro </I>and <I>in vivo</I>},
    journal = {Journal of Animal and Veterinary Advances},
    volume = {11},
    number = {13},
    pages = {2327-2332},
    year = {2012},
    issn = {1680-5593},
    doi = {javaa.2012.2327.2332},
    url = {https://makhillpublications.co/view-article.php?issn=1680-5593&doi=javaa.2012.2327.2332},
    author = {Hong-Xia,Jian,Dian-Hong,Zhi-Jie,Xiao-Hua,Fei-Long and},
    keywords = {Mycoplasma gallisepticum,enrofloxacin,ciprofloxacin,quinolone resistance-determining regions,poultry flocks},
    abstract = {The role of mutations in genes for GyrA, GyrB, ParC and ParE in fluoroquinolone-resistance in <I>Mycoplasma gallisepticum</I> obtained <I>in vitro</I> and <I>in vivo</I> was studied. <I>M. gallisepticum</I> mutants were generated by stepwise selection in either 1/2xMIC or escalating concentration of enrofloxacin or ciprofloxacin. Seven fluoroquinolone-resistant clinical isolates of <I>M. gallisepticum</I> recovered from commercial poultry flocks with suspected chronic respiratory disease were recruited for the mutation detection of four target genes. The evolution of resistance in <I>M. gallisepticum</I> was more readily and more quickly with enrofloxacin selection than with ciprofloxacin selection. Selection with enrofloxacin gave mutations at GyrA83 (Ser&rarr;Ile) firstly and subsequent additional mutation at GyrA82 or GyrA103, combining substitution at ParC80 in association with high-level resistance to FQs. Selection with ciprofloxacin gave primary change at Gyr87 and subsequent additional alteration at ParC80, elevating the MICs for FQs significantly. The presence of alterations of both the GyrA and ParC in 7 clinical isolates of <I>M. gallisepticum</I> is in good agreement with the results from mutants selected <I>in vitro</I>. No mutations in GyrB and ParE were found in mutants selected both <I>in vitro</I> and <I>in vivo</I>.}
    }