Pan Fen, Zhao Wantong, Zhang Hong
Department of Clinical Laboratory, Shanghai Children's Hospital, Shanghai Jiaotong University, Shanghai, China.
Can J Infect Dis Med Microbiol. 2019 Jan 10;2019:5975837. doi: 10.1155/2019/5975837. eCollection 2019.
This study was to investigate the microbiological characteristics and the relationship between the time to positivity (TTP) of blood cultures and different bacterial species and to assess the clinical value of TTP in children with bloodstream infections (BSIs).
The TTP of all the blood cultures from children with suspected BSIs was retrospectively collected in 2016. The microbiological characteristics and the relationship between the TTP of blood cultures and different bacterial species were also analyzed.
A total of 808 strains were isolated from 15835 blood cultures collected, and 145 (17.9%) were Gram-negative, 636 (78.7%) were Gram-positive, and 27 (3.3%) were fungi. The bacteria were divided into definite pathogens (174), possible pathogens (592), fungi (27), and contaminants (15). The average TTP of all positive blood cultures was 30.97 and ranged from 3.23 h to 92.73 h. The TTP of Gram-negative strains was significantly shorter than that of Gram-positive strains ( < 0.001) and fungi ( = 0.032). The mean TTP for (15.60 h) was shortest within the group of Gram-negative isolates, and the mean TTP for (17.34 h) within the group of Gram-positive isolates. Significant difference of the TTP was detected in methicillin-resistant vs methicillin-susceptible , extended-spectrum beta-lactamases (ESBLs) positive vs negative , and extensive drug-resistant and non-XDR . The median TTP in patients with BSI was significantly shorter than in those without it ( < 0.001). ROC curve analysis indicated that the TTP cutoff value of CoNS, , , and was 22.72 h, 19.6 h, 18.58 h, and 16.43 h, respectively, with most sensitive and specific predictor of BSIs.
Our data acknowledged that TTP is a valuable index for the early prognosis of BSIs. TTP not only provides additional utility as a general predictor of bacteria with smear result but also provides the implication of drug-resistant organisms.
本研究旨在调查血培养的微生物学特征以及血培养阳性时间（TTP）与不同细菌种类之间的关系，并评估TTP在儿童血流感染（BSIs）中的临床价值。
回顾性收集2016年疑似BSIs儿童的所有血培养的TTP。分析血培养的微生物学特征以及血培养TTP与不同细菌种类之间的关系。
从收集的15835份血培养中分离出808株菌株，其中革兰阴性菌145株（17.9%），革兰阳性菌636株（78.7%），真菌27株（3.3%）。这些细菌分为明确病原体（174株）、可能病原体（592株）、真菌（27株）和污染物（15株）。所有阳性血培养的平均TTP为30.97小时，范围为3.23小时至92.73小时。革兰阴性菌株的TTP明显短于革兰阳性菌株（<0.001）和真菌（=0.032）。在革兰阴性菌分离株组中，大肠埃希菌的平均TTP最短（15.60小时），在革兰阳性菌分离株组中，金黄色葡萄球菌的平均TTP最短（17.34小时）。在耐甲氧西林与甲氧西林敏感金黄色葡萄球菌、产超广谱β-内酰胺酶（ESBLs）阳性与阴性大肠埃希菌以及广泛耐药和非广泛耐药鲍曼不动杆菌之间检测到TTP的显著差异。BSIs患者的中位TTP明显短于无BSIs患者（<0.001）。ROC曲线分析表明，凝固酶阴性葡萄球菌、大肠埃希菌、金黄色葡萄球菌和鲍曼不动杆菌的TTP截断值分别为22.72小时、19.6小时、18.58小时和16.43小时，是BSIs最敏感和特异的预测指标。
我们的数据表明，TTP是BSIs早期预后的一个有价值的指标。TTP不仅作为细菌涂片结果的一般预测指标具有额外的作用，还能提示耐药菌的情况。
