Kuo Shu-Fang, Huang Tsung-Yu, Lee Chih-Yi, Lee Chen-Hsiang
Department of Laboratory Medicine, Chiayi Chang Gung Memorial Hospital, Chiayi 613, Taiwan.
Department of Medical Biotechnology and Laboratory Sciences, College of Medicine, Chang Gung University, Taoyuan 333, Taiwan.
Diagnostics (Basel). 2024 Jul 26;14(15):1611. doi: 10.3390/diagnostics14151611.
Timely pathogen identification in bloodstream infections is crucial for patient care. A comparison is made between positive blood culture (BC) pellets from serum separator tubes using a direct identification (DI) method and colonies on agar plates from a short-term incubation (STI) method with a matrix-assisted laser desorption/ionization Biotyper for the evaluation of 354 monomicrobial BCs. Both the DI and STI methods exhibited similar identification rates for different types of bacteria, except for Gram-positive and anaerobic bacteria. The DI method's results aligned closely with the STI method's results for Enterobacterales, glucose-non-fermenting Gram-negative bacilli (GNB), and carbapenem-resistant Enterobacterales. The DI method exhibited high concordance with the conventional method for GNB identification, achieving 88.2 and 87.5% accuracy at the genus and species levels, respectively. Compared with the STI method, the DI method showed a less successful performance for Gram-positive bacterial identification (50.5 vs. 71.3%; < 0.01). The DI method was useful for anaerobic bacterial identification of slow-growing microorganisms without any need for colony growth, unlike in the STI method (46.7 vs. 13.3%; = 0.04). However, both methods could not identify yeast in positive BCs. Overall, the DI method provided reliable results for GNB identification, offering many advantages over the STI method by significantly reducing the turnaround time and enabling quicker pathogen identification in positive BCs.
血流感染中及时进行病原体鉴定对患者护理至关重要。使用直接鉴定（DI）方法对血清分离管中的阳性血培养（BC）沉淀与采用基质辅助激光解吸/电离生物分型仪的短期培养（STI）方法在琼脂平板上的菌落进行比较，以评估354份单一微生物血培养。除革兰氏阳性菌和厌氧菌外，DI和STI方法对不同类型细菌的鉴定率相似。对于肠杆菌科、葡萄糖非发酵革兰氏阴性杆菌（GNB）和耐碳青霉烯肠杆菌科，DI方法的结果与STI方法的结果密切一致。DI方法在GNB鉴定方面与传统方法具有高度一致性，在属和种水平的准确率分别达到88.2%和87.5%。与STI方法相比，DI方法在革兰氏阳性菌鉴定方面表现较差（50.5%对71.3%；<0.01）。与STI方法不同，DI方法可用于厌氧细菌中生长缓慢微生物的鉴定，无需菌落生长（46.7%对13.3%；=0.04）。然而，两种方法均无法鉴定阳性血培养中的酵母。总体而言，DI方法为GNB鉴定提供了可靠结果，与STI方法相比具有许多优势，可显著缩短周转时间并在阳性血培养中更快地鉴定病原体。
