Objectives

Procalcitonin (PCT) is an early diagnosis marker of sepsis/bacteremia. However, some reports refer to its lower responsiveness to gram-positive bacteremia. We retrospectively evaluated the PCT values at the onset of bacteremia in relation to severity index.

Methods

Patients with bacteremia caused by two gram-negative bacteria (46 E. coli and 50 Klebsiella pneumoniae) and three gram-positive bacteria (45 S. aureus, 56 S. epidermidis, and 10 S. mitis) were studied. The plasma PCT and C-reactive protein (CRP) levels were compared between species and different Sequential Organ Failure Assessment (SOFA) score groups.

Results

The median PCT level was higher in gram-negative than in gram-positive bacteremia in overall (13.09 vs. 0.50 ng/mL, p < 0.0001), in SOFA score≥4 group (28.85 vs.1.72 ng/mL, p < 0.0001) and in SOFA<4 group (2.64 vs. 0.42 ng/mL, p < 0.0001). Only 46%, and 11% of patients showed PCT ≥0.5 ng/mL in S. epidermidis, and S. mitis bacteremia, respectively. PCT was significantly better than CRP in discriminating gram-negative from gram-positive bacteremia (AUCROC; 0.828 and 0.634, p < 0.001), but it was low in Staphylococcus epidermidis bacteremia regardless of SOFA scores.

Conclusions

PCT levels are lower in gram-positive bacteremia regardless of SOFA scores or the presence of shock. The conventional sepsis cutoff of 0.5 ng/mL may overlook certain proportions of gram-positive bacteremia.

中文翻译：

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无论严重程度或是否存在休克，革兰阳性菌血症发作时血浆降钙素原水平仍然较低：对具有详细临床特征的患者的回顾性分析

目标

降钙素原 (PCT) 是败血症/菌血症的早期诊断标志物。然而，一些报道提到其对革兰氏阳性菌血症的反应性较低。我们回顾性评估了菌血症发作时与严重程度指数相关的 PCT 值。

方法

研究了由两种革兰氏阴性菌（46 种大肠杆菌和 50 种肺炎克雷伯菌）和三种革兰氏阳性菌（45 种 金黄色葡萄球菌、56 种表皮葡萄球菌和 10 种S.mitis）引起的菌血症患者。比较物种和不同顺序器官衰竭评估 (SOFA) 评分组之间的血浆 PCT 和 C 反应蛋白 (CRP) 水平。

结果

 在 SOFA 评分≥4 组（28.85 vs.1.72 ng/mL， p < 0.0001）中，革兰氏阴性菌血症的中位 PCT 水平总体高于革兰氏阳性菌血症（13.09 vs. 0.50 ng/mL，p < 0.0001） ) 和 SOFA<4 组 (2.64 vs. 0.42 ng/mL, p  < 0.0001)。只有 46% 和 11% 的患者在表皮葡萄球菌和缓症链球菌菌血症中分别显示 PCT ≥0.5 ng/mL。在区分革兰氏阴性菌和革兰氏阳性菌血症方面，PCT 显着优于 CRP（AUCROC；0.828 和 0.634，p  < 0.001），但无论 SOFA 评分如何，它在表皮葡萄球菌菌血症中的表现都较低。

结论

无论 SOFA 评分或是否存在休克，革兰氏阳性菌血症的 PCT 水平较低。0.5 ng/mL 的常规脓毒症临界值可能会忽略某些革兰氏阳性菌血症的比例。