Department of Urology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan.
Int J Urol. 2012 Apr;19(4):360-8. doi: 10.1111/j.1442-2042.2011.02933.x. Epub 2011 Dec 29.
Coincident with their worldwide use, resistance to fluoroquinolones in Escherichia coli has increased. To identify the gene expression profiles underlying fluoroquinolone resistance, we carried out genome-wide transcriptome analysis of fluoroquinolone-sensitive E. coli.
Four fluoroquinolone-sensitive E. coli and five fluoroquinolone-resistant E. coli clinical isolates were subjected to complementary deoxyribonucleic acid microarray analysis. Some upregulated genes' expression was verified by real-time polymerase chain reaction using 104 E. coli clinical isolates, and minimum inhibitory concentration tests were carried out by using their transformants.
A total of 40 genes were significantly upregulated in fluoroquinolone-resistant E. coli isolates (P < 0.05). The expression of phage shock protein operons, which are involved in biofilm formation, was markedly upregulated in our profile of fluoroquinolone-resistant E. coli. One of the phage shock protein operons, pspC, was significantly upregulated in 50 fluoroquinolone-resistant E. coli isolates (P < 0.0001). The expression of type I fimbriae genes, which are pilus operons involved in biofilm formation, were markedly downregulated in fluoroquinolone-resistant E. coli. Deoxyribonucleic acid adenine methyltransferase (dam), which represses type I fimbriae genes, was significantly upregulated in the clinical fluoroquinolone-resistant E. coli isolates (P = 0.007). We established pspC- and dam-expressing E. coli transformants from fluoroquinolone-sensitive E. coli, and the minimum inhibitory concentration tests showed that the transformants acquired fluoroquinolone resistance, suggesting that upregulation of these genes contributes to acquiring fluoroquinolone resistance.
Upregulation of psp operones and dam underlying pilus operons downregulation might be associated with fluoroquinolone resistance in E. coli.
随着氟喹诺酮类药物在世界范围内的使用，大肠杆菌对氟喹诺酮类药物的耐药性也有所增加。为了确定氟喹诺酮类药物耐药性的基因表达谱，我们对氟喹诺酮类敏感的大肠杆菌进行了全基因组转录组分析。
对 4 株氟喹诺酮类敏感的大肠杆菌和 5 株氟喹诺酮类耐药的大肠杆菌临床分离株进行互补脱氧核糖核酸微阵列分析。利用实时聚合酶链反应对一些上调基因的表达进行了验证，并对 104 株大肠杆菌临床分离株进行了最小抑菌浓度试验，然后用它们的转化株进行试验。
在氟喹诺酮类耐药的大肠杆菌分离株中，共有 40 个基因显著上调（P<0.05）。在我们的氟喹诺酮类耐药大肠杆菌图谱中，噬菌体休克蛋白操纵子的表达明显上调，噬菌体休克蛋白操纵子参与生物膜的形成。其中一个噬菌体休克蛋白操纵子 pspC 在 50 株氟喹诺酮类耐药的大肠杆菌中显著上调（P<0.0001）。参与生物膜形成的菌毛操纵子 I 型菌毛基因的表达在氟喹诺酮类耐药的大肠杆菌中明显下调。脱氧腺嘌呤甲基转移酶（dam），它抑制 I 型菌毛基因的表达，在临床氟喹诺酮类耐药的大肠杆菌分离株中显著上调（P=0.007）。我们从氟喹诺酮类敏感的大肠杆菌中建立了 pspC 和 dam 表达的大肠杆菌转化株，最小抑菌浓度试验表明，转化株获得了氟喹诺酮类耐药性，这表明这些基因的上调有助于获得氟喹诺酮类耐药性。
psp 操纵子和 dam 的上调，可能与大肠杆菌中氟喹诺酮类药物的耐药性有关。
