Objective: The use of matrix-assisted laser desorption/ionisation-time of flight mass spectrometry (MALDI) directly on urine can significantly improve turnaround time for diagnosing urinary tract infection (UTI). The present study was planned to compare the performance of MALDI directly on urine samples with conventional urine culture and evaluate an algorithm using a combination of significant pyuria and MALDI directly on urine samples as a screening method for diagnosing UTI. Materials and Methods: A total of 1000 urine samples from patients with symptoms suggestive of UTIs were analysed. Urine microscopy, urine culture and MALDI were performed simultaneously on all the samples. Results: MALDI correctly identified the microorganisms in 73.83% monomicrobial samples. In culture showing a mixed growth of two and more than three organisms, MALDI was able to identify one microorganism in 27.58% and 15.78% of samples, respectively. There were no peaks by MALDI in 93.53% of 464 sterile samples. The sequential algorithm using urine microscopy and MALDI could correctly identify UTI in 66.23% cases. Conclusion: MALDI can be utilised to rule out bacteriuria in >93% of sterile urine samples. The combination of significant pyuria and direct MALDI as screening method to diagnose UTI (whether monomicrobial or polymicrobial) was not found to be superior than using direct MALDI on urine samples alone.


中文翻译：

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基质辅助激光解吸电离飞行时间质谱法直接鉴定尿样菌尿的评价



目的：直接对尿液使用基质辅助激光解吸/电离飞行时间质谱 (MALDI) 可以显着缩短诊断尿路感染 (UTI) 的周转时间。本研究计划比较直接检测尿液样本的 MALDI 与传统尿液培养的性能，并评估使用显着脓尿和直接检测尿液样本的 MALDI 相结合的算法作为诊断 UTI 的筛查方法。材料和方法：总共分析了 1000 份来自有尿路感染症状的患者的尿液样本。对所有样本同时进行尿液显微镜检查、尿液培养和 MALDI。结果： MALDI 正确鉴定了 73.83% 的单一微生物样品中的微生物。在两种和三种以上生物体混合生长的培养物中，MALDI 能够分别在 27.58% 和 15.78% 的样品中识别出一种微生物。 464 个无菌样品中，93.53% 的 MALDI 没有出现峰。使用尿液显微镜和 MALDI 的序贯算法可以正确识别 66.23% 的病例中的 UTI。结论： MALDI 可用于排除 >93% 的无菌尿样中的菌尿。未发现显着脓尿和直接 MALDI 相结合作为诊断 UTI（无论是单一微生物还是多种微生物）的筛查方法优于单独对尿样使用直接 MALDI。