Johnson J R, Tiu F S, Stamm W E
Department of Medicine, University of Minnesota, Minneapolis, USA.
J Clin Microbiol. 1995 Sep;33(9):2316-23. doi: 10.1128/jcm.33.9.2316-2323.1995.
Despite its theoretical advantages, direct antimicrobial susceptibility testing (DST) of urine specimens remains controversial largely because of concerns regarding its accuracy, particularly with mixed cultures. To evaluate the performance of DST in the setting of acute urinary tract infection (UTI), we performed DST using 25 traditional and contemporary antimicrobial agents on urine specimens from 162 women with suspected acute uncomplicated UTI, and compared these results with the results of standardized disk diffusion susceptibility tests done on the same specimens. Direct tests were interpretable for 129 specimens, i.e., 80% of all specimens and 85% of the 152 specimens that met the culture criteria for UTI. Of the 2,983 individual comparisons between the direct and standard tests, 0.8% represented very major errors, 0.6% represented major errors, 3.1% represented minor errors, and 95.5% were in agreement. Errors were more common in association with older antimicrobial agents and agents with a high prevalence of antimicrobial resistance, non-Escherichia coli strains, low urine bacterial concentrations, sparse or mixed growth in the direct test, and the presence of multiple significant organisms in urine. The urine leukocyte concentration was > or = 15/mm3 in all subjects and did not differentiate between specimens that gave an interpretable direct test and those that did not. Calculation of the sensitivity of DST in identifying antimicrobial resistance supplemented conventional error rate analysis. We conclude that when used selectively and interpreted carefully, DST of urine specimens offers an efficient, rapid, and accurate method for antimicrobial susceptibility determination for acute UTI, particularly when the urine bacterial concentration is > 10(5) CFU/ml.
尽管尿液标本直接药敏试验（DST）具有理论上的优势，但仍颇具争议，主要原因是人们担心其准确性，尤其是对于混合培养物。为了评估DST在急性尿路感染（UTI）中的性能，我们使用25种传统和现代抗菌药物对162名疑似急性单纯性UTI的女性尿液标本进行了DST，并将这些结果与对相同标本进行的标准化纸片扩散药敏试验结果进行了比较。129份标本的直接试验结果可解释，即占所有标本的80%，以及符合UTI培养标准的152份标本中的85%。在直接试验和标准试验之间的2983次个体比较中，0.8%为极重大错误，0.6%为重大错误，3.1%为 minor错误，95.5%一致。错误在与较老的抗菌药物、抗菌耐药性高的药物、非大肠杆菌菌株、尿液细菌浓度低、直接试验中生长稀疏或混合生长以及尿液中存在多种重要微生物相关时更为常见。所有受试者的尿液白细胞浓度均≥15/mm3，且在可解释直接试验结果的标本和不可解释的标本之间没有区分。计算DST在识别抗菌耐药性方面的敏感性补充了传统错误率分析。我们得出结论，当有选择地使用并仔细解释时，尿液标本的DST为急性UTI的抗菌药敏测定提供了一种高效、快速且准确的方法，尤其是当尿液细菌浓度>10(5) CFU/ml时。
