Urinary tract infections are one of the most common bacterial infections and rapid diagnosis of the infection is essential for appropriate antibiotic therapy. The goal of our study was to identify urinary pathogens directly by MALDI-TOF MS and to perform antibiotic susceptibility tests in order to shorten the period spent for culturing.Urine samples submitted for culture to the Clinical Microbiology Laboratory were enrolled in this study. Urine samples were screened for leukocyte and bacteria amount by flow cytometry. Samples with bacterial load of 106-107/mL were tested directly by MALDI-TOF MS and antibiotic susceptibility tests (AST) were performed.In total, 538 positive urine samples were evaluated in our study. MALDI-TOF MS identified the microorganism directly from the urine sample in 91.8% of these samples and the concordance rate of conventional identification and direct detection was 95.8% for Gram-negatives at the genus and species level. Escherichia coli (n:401) was the most frequently isolated microorganism, followed by Klebsiella pneumoniae (n:57). AST results were generated for 111 of these urine samples and the concordance was 90% and 87% for E. coli and K. pneumoniae, respectively.Our results showed that screening of urine samples with flow cytometry to detect positive samples and identification of uropathogens directly by MALDI-TOF MS with an accuracy of over 90% can be a suitable method particularly for Gram-negative bacteria in clinical microbiology laboratories.

中文翻译：

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尿液培养的替代方法：通过MALDI-TOF MS从尿液中直接鉴定尿毒症。

尿路感染是最常见的细菌感染之一，感染的快速诊断对于适当的抗生素治疗至关重要。本研究的目的是通过MALDI-TOF MS直接鉴定尿中的病原体并进行抗生素敏感性测试，以缩短培养时间。本研究纳入了提交给临床微生物学实验室进行培养的尿液样本。通过流式细胞仪筛选尿液样本中的白细胞和细菌数量。通过MALDI-TOF MS直接检测细菌载量为106-107 / mL的样品，并进行抗生素敏感性测试（AST）。在本研究中，总共评估了538个阳性尿液样品。MALDI-TOF MS在91中直接从尿液样本中鉴定出了微生物。这些样本中有8％与常规鉴定和直接检测的革兰氏阴性菌在属和种水平上的一致率为95.8％。大肠杆菌（n：401）是最常见的分离微生物，其次是肺炎克雷伯菌（n：57）。这些尿液样本中有111种产生AST结果，大肠杆菌和肺炎克雷伯菌的一致性分别为90％和87％。我们的结果表明，使用流式细胞仪筛选尿液样本以检测阳性样本并直接鉴定尿毒症MALDI-TOF MS的90％以上准确度可能是一种合适的方法，尤其适用于临床微生物学实验室中的革兰氏阴性细菌。401）是最常见的分离微生物，其次是肺炎克雷伯菌（n：57）。这些尿液样本中有111种产生AST结果，大肠杆菌和肺炎克雷伯菌的一致性分别为90％和87％。我们的结果表明，使用流式细胞仪筛选尿液样本以检测阳性样本并直接鉴定尿毒症MALDI-TOF MS的90％以上准确度可能是一种合适的方法，尤其适用于临床微生物学实验室中的革兰氏阴性细菌。401）是最常见的分离微生物，其次是肺炎克雷伯菌（n：57）。这些尿液样本中有111种产生AST结果，大肠杆菌和肺炎克雷伯菌的一致性分别为90％和87％。我们的结果表明，使用流式细胞仪筛选尿液样本以检测阳性样本并直接鉴定尿毒症MALDI-TOF MS的90％以上准确度可能是一种合适的方法，尤其适用于临床微生物学实验室中的革兰氏阴性细菌。