降钙素原在败血症患者中鉴别血流感染 细菌种类的意义

目的 探讨血清降钙素原（PCT）水平对鉴别败血症患者血流感染细菌种类的临床应用价值。方法 选取2014 年7 月-2016 年6 月广东省佛山市三水区人民医院入院第1 天检测血清PCT 水平、白细胞及C 反 应蛋白（CRP）水平的败血症患者为研究对象。比较血清PCT 水平在各种细菌血流感染患者之间的差异，并 同时采用受试者工作曲线（ROC）判断PCT、CRP 区分革兰阴性（G-）菌和革兰阳性（G+）菌血流感染的诊 断性能。结果 纳入有效细菌血流感染败血症患者339 例：G- 菌感染组226 例，G+ 菌感染组113 例，两组PCT 水平中位数分别为8.03（1.37 ～ 36.05）ng/ml 和0.63（0.22 ～ 4.68）ng/ml，两组间PCT 水平差异有统计学 意义（P <0.05）。G- 菌组内各种主要阴性菌感染患者血清PCT 水平比较总体差异无统计学意义（P >0.05）； G+ 菌组内各种主要阳性菌感染患者血清PCT 水平比较总体差异有统计学意义（P <0.05）；界值设定为2 ng/ml 时， 血清PCT 水平区分G- 与G+ 菌所致血流感染的敏感性为71.2%，特异性为64.6% ；鉴别G- 与菌G+ 菌的ROC 曲线下面积为72.1（P <0.05）。结论 血清PCT 对鉴别G- 菌与G+ 菌引起的血流感染患者有较好的临床应用 意义；PCT 对鉴别G- 菌组内各种阴性菌引起血流感染无临床意义，可以用于鉴别链球菌或金黄色葡萄球菌 与凝固酶阴性葡萄球菌引起的血流感染。

Significance of procalcitonin in differentiation of bacterial species causing bloodstream infection in patients with septicemia

Objective To study the clinical values of procalcitonin (PCT) level in identifying the species of bacteria causing bloodstream infection in patients with septicemia. Methods All the patients with septicemia admitted into our hospital from July 2014 to June 2016 were the objects of this study. And on the 1st day their serum PCT level, WBC and CRP level were tested. During the study, the differences of serum PCT levels were compared among the patients with septicemia caused by different bacteria. At the same time the receiver operating curve (ROC) was used to study the diagnostic efficiency of PCT and CRP in differentiation of bloodstream infections caused by Gram-negative (G-) bacteria and Gram-positive (G+) bacteria. Results In this study, there were 339 cases of bacterial bloodstream infection, including 226 cases with G- bacterial infections and 113 cases with G+ bacterial infections. The median PCT levels of the G- group and the G+ group were 8.03 (1.37-36.05) ng/ml and 0.63 (0.22-4.68) ng/ml, the difference of serum PCT levels between the two groups had statistical significance (P < 0.05). In the G- group, there were no significant differences in serum PCT levels among the patients with different major G- bacterial infections (P > 0.05). The differences of serum PCT levels among the patients with differrnt major G+ bacterial infections from G+ group had statistical significance (P < 0.05). When the cutoff value was set to 2 ng/ml, the sensitivity of serum PCT level on distinguishing bloodstream infections caused by G- and G+ bacteria was 71.2% and the specificity was 64.6%. The area under ROC to distinguish G- and G+ bacteria was 72.1 (P < 0.05). Conclusions Serum PCT level has good clinic application value in distinguishing bloodstream infections caused by G- bacteria and G+ bacteria. Serum PCT level has no clinic application value in distinguishing bloodstream infections caused by different G- bacteria. However, PCT level can distinguish the bloodstream infections caused by Streptococcus or Staphylococcus aureus from those caused by coagulase negative Staphylococci.