Ehsanipour Fahime, Noorbakhsh Samileh, Zarabi Vida, Movahedi Zahra, Rahimzadeh Nahid
Pediatric Infectious Diseases Department, Iran University of Medical Sciences, Tehran. Iran.
Pediatric Infectious Diseases Department, Qom University of Medical Sciences and health services, Qom. Iran.
Curr Pediatr Rev. 2017;13(2):152-156. doi: 10.2174/1573396313666170216154528.
Pyelonephritis is the most common and important infection among Iranian pediatric population. Differentiation between upper and lower Urinary Tract Infection (UTI) is often difficult based on clinical data. Therefore, definite diagnosis is helpful for choosing appropriate antibiotic and decision for hospital admission. The main purpose of this study was todetermine the diagnostic value of serum STREM-1 level in children suspicious to UTI and differentiation of upper UTI and lower UTI.
MATERIAL & METHODS: This prospective cross sectional study (2010-2011) was performed to evaluate and compare the serum level of STREM- 1 (pg. /ml) in 36 diagnosed UTI patients (24 upper and 12 lower UTI) with 25 normal children (without UTI) in Rasoul Akram hospital, Tehran, Iran. The mean age of studied children was 3.64 years; 24 male and 37 female. Urinary analysis and urine culture were performed for all UTI cases and only the positive cultured cases with the same microorganism were enrolled in the study. Distinguishing the upper from lower UTI was done on the basis of clinical manifestation and laboratory tests and confirmed by Imaging studies (ultra sonography /or DMSA scan). Blood sampling was taken from all children and centrifuged .The level of STREM-1 (pg /ml) in all sera was determined by Enzyme immunoassay technique (Human TREM-1 immunoassay Sandwich test, Quantikine, R&D systems, Minneapolis; USA). Cut-off levels for STREM-1 were illustrated by ROC curve. The p<0.05 was considered as significant for differences between groups.
The mean of STREM -1level had significant difference between overall cases of UTI (427.72pg/ml) and controls (124.24 pg. /ml; P =0.000) ; with cutoff point 111.5 pg./ml ; it had 83.3% sensitivity; and 60 % specificity to distinguish UTI from control. Serum STREM -1 level had no significantly difference between the upper and lower UTI (500pg/ml vs. 283 pg. /ml, P value=0.1) with cutoff point 132 pg./ml it had 83.3% sensitivity ; and 60 % specificity to distinguish upper UTI from lower UTI.
Our study demonstrates that even low amount of serum STREM-1 (111.5 pg./ml) has 83.3% sensitivity ; and 60 % specificity to distinguish the UTI from normal cases (P value =0.000) but higher level (132 pg./ml) was needed for definite diagnosis (83.3% sensitivity; 60 % specificity) of upper and lower UTI. It is concluded that serum STREM-1 level test is a valuable tool for early diagnosis of the normal cases with false positive urine culture, or in highly suspicious upper UTI cases with false negative urine culture. Indeed higher titer of this biomarker could be helpful for discriminating the upper from lower UTI. Therefore adding this new biologic marker (STREM-1) to previous ones (CRP, PCT) is suggested to prevent the unnecessary hospital admission and empiric antibiotic therapy.
肾盂肾炎是伊朗儿童群体中最常见且最重要的感染性疾病。基于临床数据，区分上尿路感染和下尿路感染往往存在困难。因此，明确诊断有助于选择合适的抗生素以及决定是否住院治疗。本研究的主要目的是确定血清STREM-1水平在疑似尿路感染儿童中的诊断价值，以及区分上尿路感染和下尿路感染。
这项前瞻性横断面研究（2010 - 2011年）在伊朗德黑兰拉苏勒·阿克拉姆医院进行，旨在评估并比较36例确诊的尿路感染患者（24例上尿路感染和12例下尿路感染）与25例正常儿童（无尿路感染）的血清STREM-1水平（pg/ml）。研究儿童的平均年龄为3.64岁；男性24例，女性37例。对所有尿路感染病例进行尿液分析和尿培养，仅将培养出相同微生物的阳性病例纳入研究。根据临床表现和实验室检查区分上尿路感染和下尿路感染，并通过影像学检查（超声或二巯基丁二酸肾动态显像扫描）进行确认。对所有儿童进行采血并离心。采用酶免疫测定技术（人TREM-1免疫测定夹心试验，Quantikine，R&D systems，明尼阿波利斯，美国）测定所有血清中STREM-1的水平（pg/ml）。通过ROC曲线确定STREM-1的临界值。两组间差异以p<0.05为有统计学意义。
尿路感染总体病例的STREM-1水平均值（427.72pg/ml）与对照组（124.24 pg/ml；P =0.000）之间存在显著差异；临界值为111.5 pg/ml时，区分尿路感染与对照组的灵敏度为83.3%，特异性为60%。上尿路感染和下尿路感染患者的血清STREM-1水平无显著差异（500pg/ml对283 pg/ml，P值 =0.1），临界值为132 pg/ml时，区分上尿路感染与下尿路感染的灵敏度为83.3%，特异性为60%。
我们的研究表明，即使血清STREM-1水平较低（111.5 pg/ml），区分尿路感染与正常病例也具有83.3%的灵敏度和60%的特异性（P值 =0.000），但明确诊断上尿路感染和下尿路感染需要更高的水平（132 pg/ml，灵敏度83.3%，特异性60%）。得出结论，血清STREM-1水平检测对于尿培养假阳性的正常病例早期诊断，或高度疑似上尿路感染但尿培养假阴性的病例是一种有价值的工具。事实上，该生物标志物的较高滴度有助于区分上尿路感染和下尿路感染。因此，建议将这种新的生物标志物（STREM-1）添加到先前的标志物（CRP、PCT）中，以避免不必要的住院治疗和经验性抗生素治疗。
