Abstract: Objective　To explore the application value of procalcitonin (PCT) in the identification of bacteria for bloodstream infection in newborns. Methods　A total of 198 cases of neonatal bloodstream infection were selected from Tengzhou Central People's Hospital Affiliated to Jining Medical University from January 2019 to December 2021 for a retrospective analysis. According to the blood culture results, they were divided into a Gram-negative group (86 cases) and a Gram-positive group (112 cases). Meanwhile, 90 children with negative blood culture results were selected as the control group. There were 45 males and 41 females in the Gram-negative group with an age of (15.15±2.63) days old; there were 58 males and 54 females in the Gram-positive group with an age of (15.35±2.41) days old; there were 47 males and 43 females in the control group with an age of (15.65±2.78) days old. The levels of PCT, C-reactive protein (CRP), and white blood cell count (WBC) in the three groups were measured and compared, the composition ratio of bacteria and the level of serum PCT were observed, and the serum PCT levels in the Gram-negative group and the Gram-positive group were compared. F test and chi-square test were used. Results　The levels of PCT [(7.53±1.93) μg/L and (2.91±0.83) μg/L], CRP [(37.32±16.61) mg/L and (30.73±15.94) mg/L], WBC [(17.23±3.43) ×10⁹/L and (15.53±3.12) ×10⁹/L] in the Gram-negative and Gram-positive groups were higher than those in the control group [(0.07±0.02) μg/L, (9.32±3.35) mg/L, and (8.54±2.37) ×10⁹/L], with statistically significant differences (all P<0.05). The PCT level of the Gram-negative group was higher than that of the Gram-positive group [(7.53±1.93) μg/L vs. (2.91±0.83) μg/L], with a statistically significant difference (P<0.05). The sensitivity, specificity, positive predictive value, negative predictive value, and Youden index of PCT in predicting neonatal bloodstream infection were 94.44%, 92.22%, 96.39%, 88.30%, and 86.67%, respectively, which were higher than those of CRP and WBC, with statistically significant differences (all P<0.05). The main bacteria detected in the blood culture were Escherichia coli, Staphylococcus epidermidis, and Klebsiella pneumoniae, accounting for 41.86% (36/86), 38.39% (43/112), and 27.91% (24/86), respectively. The level of PCT was the highest in newborns with Klebsiella pneumoniae infection [(11.21±3.32) μg/L], followed by Escherichia coli [(9.32±3.43) μg/L]. There was a statistically significant difference in the PCT distribution between the Gram-negative and Gram-positive groups (P<0.05). Conclusion　The application value of PCT in the identification of bacteria for bloodstream infection in newborns is higher, it can be used to identify the type of bacterial infection and to provide basis for early diagnosis and treatment.

Key words: Procalcitonin, Newborns, Bloodstream infection, Identification of bacteria

摘要： 目的　探讨降钙素原（PCT）在新生儿血流感染细菌鉴定中的应用价值。方法　选取2019年1月至2021年12月在济宁医学院附属滕州市中心人民医院接受治疗的198例新生儿血流感染为研究对象，进行回顾性分析，根据血培养结果，分为革兰阴性菌组（86例）和革兰阳性菌组（112例），同时选取90例血培养阴性患儿为对照组。革兰阴性菌组男45例、女41例，日龄（15.15±2.63）d；革兰阳性菌组男58例、女54例，日龄（15.35±2.41）d；对照组男47例、女43例，日龄（15.65±2.78）d。对3组PCT、C反应蛋白（CRP）、白细胞计数（WBC）水平进行检测与比较，观察检出菌构成比及相应血清PCT水平，同时比较革兰阴性菌组与革兰阳性菌组血清PCT水平分布情况。采用F检验、χ²检验。结果　革兰阴性菌组和革兰阳性菌组PCT［（7.53±1.93）μg/L、（2.91±0.83）μg/L］、CRP［（37.32±16.61）mg/L、（30.73±15.94）mg/L］、WBC［（17.23±3.43）×10⁹/L、（15.53±3.12）×10⁹/L］水平均高于对照组［（0.07±0.02）μg/L、（9.32±3.35）mg/L、（8.54±2.37）×10⁹/L］，差异均有统计学意义（均P<0.05）；革兰阴性菌组PCT水平高于革兰阳性菌组［（7.53±1.93）μg/L比（2.91±0.83）μg/L］，差异有统计学意义（P<0.05）。PCT检测诊断新生儿血流感染的灵敏度、特异度、阳性预测值、阴性预测值及约登指数分别为94.44%、92.22%、96.39%、88.30%、86.67%，均高于CRP和WBC，差异均有统计学意义（均P<0.05）。血培养检出菌以大肠埃希菌、表皮葡萄球菌、肺炎克雷伯菌为主，分别占41.86%（36/86）、38.39%（43/112）、27.91%（24/86）；PCT水平最高为肺炎克雷伯菌感染新生儿［（11.21±3.32）μg/L］，其次为大肠埃希菌感染新生儿［（9.32±3.43）μg/L］。革兰阴性菌组与革兰阳性菌组PCT分布差异有统计学意义（P<0.05）。结论　PCT在新生儿血流感染细菌鉴定中的应用价值较高，可用于鉴别细菌感染类型，为早期诊断和治疗提供依据。

关键词: 降钙素原, 新生儿, 血流感染, 细菌鉴定