牛源致病性大肠杆菌耐氟苯尼考floR基因的克隆与序列分析

Cloning and Sequence Analysis of floR Genes Isolated from Bovine Pathogenic Escherichia coli

对临床分离的12株牛腹泻大肠杆菌进行了血清型鉴定,毒力因子分析和MICs值测定。利用PCR方法对上述致病性大肠杆菌进行了floR基因的检测,其中5株floR阳性。对其中的3株大肠杆菌的耐氟苯尼考floR基因进行了克隆和序列分析。结果表明,克隆的floR基因所推倒的氨基酸序列与其他12-跨膜外输泵家族在共同的基序上是保守的,在克隆的floR序列与已报道的floR序列间仅存在1个或2个氨基酸替代。

Twelve E.coli isolates associated with bovine diarrhea were investigated for associated disease serotypes,virulence factors,and antimicrobial susceptibility pattern.The presence of floR gene was detected via PCR.Of all the isolates,42%(5/12) were floR positive.Three floR positive clones were sequenced and designated as C286(AY517519),C260(AY499129),and C262(AY499130),respectively.Sequence Analysis revealed the common motifs with 12-transmembrane segments efflux pumps family were conserved in the deduced floR amino acid sequences.One or two amino acid residue substitutions appeared between the cloned floR genes and reported floR genes sequences.