Yu Xiaolei, Susa Milorad, Weile Jan, Knabbe Cornelius, Schmid Rolf D, Bachmann Till T
Institute of Technical Biochemistry, University of Stuttgart, Germany.
Int J Med Microbiol. 2007 Oct;297(6):417-29. doi: 10.1016/j.ijmm.2007.03.018. Epub 2007 May 7.
Urinary tract infections (UTI) are among the most common bacterial infections in humans, with Escherichia coli being the major cause of infection. Fluoroquinolone resistance of uropathogenic E. coli has increased significantly over the last decade. In this study a microarray-based assay was developed and applied, which provides a rapid, sensitive and specific detection of fluoroquinolone-resistant E. coli in urine. The capture probes were designed against previously identified and described hotspots for quinolone resistance (codons 83 and 87 of gyrA). The key goals of this development were to reduce assay time while increasing the sensitivity and specificity as compared with a pilot version of a gyrA genotyping DNA microarray. The performance of the assay was demonstrated with pure cultures of 30 E. coli isolates as well as with urine samples spiked with 6 E. coli isolates. The microarray results were confirmed by standard DNA sequencing and were in full agreement with the phenotypic antimicrobial susceptibility testing using standard methods. The DNA microarray test displayed an assay time of 3.5h, a sensitivity of 100CFU/ml, and the ability to detect fluoroquinolone-resistant E. coli in the presence of a 10-fold excess of fluoroquinolone-susceptible E. coli cells. As a consequence, we believe that this microarray-based determination of antibiotics resistance has a true potential for the application in clinical routine laboratories in the future.
尿路感染（UTI）是人类最常见的细菌感染之一，大肠杆菌是主要的感染源。在过去十年中，尿路致病性大肠杆菌对氟喹诺酮的耐药性显著增加。在本研究中，开发并应用了一种基于微阵列的检测方法，该方法可快速、灵敏且特异地检测尿液中耐氟喹诺酮的大肠杆菌。捕获探针是针对先前确定和描述的喹诺酮耐药热点（gyrA基因的83和87密码子）设计的。与gyrA基因分型DNA微阵列的试验版本相比，该检测方法的主要目标是缩短检测时间，同时提高灵敏度和特异性。使用30株大肠杆菌分离株的纯培养物以及添加了6株大肠杆菌分离株的尿液样本对该检测方法的性能进行了验证。微阵列结果通过标准DNA测序得到证实，并且与使用标准方法进行的表型抗菌药敏试验完全一致。DNA微阵列检测的检测时间为3.5小时，灵敏度为100CFU/ml，并且能够在存在10倍过量的氟喹诺酮敏感大肠杆菌细胞的情况下检测出耐氟喹诺酮的大肠杆菌。因此，我们认为这种基于微阵列的抗生素耐药性检测方法在未来临床常规实验室的应用中具有真正的潜力。
