Department of Microbiology, Biomedical Diagnostic Center (BDC), Hospital Clinic, University of Barcelona, Barcelona, Spain.
Consorci del Laboratori Intercomarcal de l´Alt Penedès, l´Anoia i el Garraf, Vilafranca del Penedès, Barcelona, Spain.
PLoS One. 2019 Aug 7;14(8):e0220307. doi: 10.1371/journal.pone.0220307. eCollection 2019.
Conventional microbiological procedures for the isolation of bacteria from biological fluids consist of culture on solid media and enrichment broth. However, these methods can delay the microbiological identification for up to 4 days. The aim of this study was to evaluate the analytical performance of Sysmex UF500i (Sysmex, Kobe, Japan) as a screening method for the detection of bacteria in different biological fluids in comparison with direct Gram staining and the conventional culture on solid media and enrichment broth.
A total of 479 biological fluid samples were included in the study (180 ascitic, 131 amniotic, 56 synovial, 40 cerebrospinal, 36 pleural, 24 peritoneal, 9 bile and 3 pericardial fluids). All samples were processed by conventional culture methods and analyzed by flow cytometry. Direct Gram staining was performed in 339 samples. The amount of growth on culture was recorded for positive samples.
Bacterial and white blood cell count by flow cytometry was significantly higher among culture positive samples and samples with a positive direct Gram stain compared to culture negative samples. Bacterial count directly correlated with the amount of growth on culture (Kruskall-Wallis H χ2(3) = 11.577, p = 0.009). The best specificity (95%) for bacterial count to predict culture positivity was achieved applying a cut-off value of 240 bacteria/μL.
Bacterial and white blood cell counts obtained with flow cytometry correlate with culture results in biological fluids. Bacterial count can be used as a complementary method along with the direct Gram stain to promptly detect positive samples and perform other diagnostic techniques in order to accelerate the bacterial detection and identification.
从生物体液中分离细菌的传统微生物学程序包括固体培养基和增菌肉汤培养。然而，这些方法可能会将微生物学鉴定延迟多达 4 天。本研究旨在评估 Sysmex UF500i（Sysmex，神户，日本）作为一种筛选方法，用于检测不同生物体液中的细菌，与直接革兰染色和传统固体培养基和增菌肉汤培养进行比较。
本研究共纳入 479 份生物体液样本（180 份腹水、131 份羊水、56 份滑液、40 份脑脊液、36 份胸腔积液、24 份腹膜、9 份胆汁和 3 份心包液）。所有样本均通过常规培养方法进行处理，并通过流式细胞术进行分析。在 339 份样本中进行了直接革兰染色。对培养阳性样本和直接革兰染色阳性样本进行了培养物生长量的记录。
流式细胞术检测的细菌和白细胞计数在培养阳性样本和直接革兰染色阳性样本中明显高于培养阴性样本。细菌计数与培养物生长量直接相关（Kruskal-Wallis H χ2(3) = 11.577，p = 0.009）。细菌计数预测培养阳性的最佳特异性（95%）为 240 个细菌/μL 时。
生物体液中流式细胞术检测的细菌和白细胞计数与培养结果相关。细菌计数可作为一种补充方法，与直接革兰染色一起，快速检测阳性样本，并进行其他诊断技术，以加速细菌的检测和鉴定。
