核糖体DNA聚合酶链反应诊断新生儿败血症

Clinical evaluation of 16SrDNA PCR in the diagnosis of neonatal septicemia

目的比较１６ＳｒＤＮＡ高度保守区引物聚合酶链反应（ＰＣＲ）与血培养及非特异性诊断指标对新生儿败血症的诊断价值。方法对１３１例拟诊为败血症的新生儿血标本进行细菌ＤＮＡ检测。结果１３１例中，ＰＣＲ检测阳性５６例，阳性率为４３％，明显高于血培养的阳性率（血培养阳性２３例，阳性率１８％）。１３１例拟诊败血症中，发现２３例确诊败血症及３１例临床败血症，对这５４例败血症（血培养阳性２３例＋临床败血症３１例）作ＰＣＲ检查，结果阳性４８例，阴性６例；对１３１例中的７７例“非败血症”病例，ＰＣＲ检测阴性６９例，阳性８例。对血培养阳性的２３例进行ＰＣＲ，结果阳性２２例。以血培养作为确诊标准，ＰＣＲ检测的敏感性为９６％，并不受抗生素治疗的影响。３０例阴性对照组ＤＮＡ的ＰＣＲ分析均为阴性。结论在严格控制污染的条件下。

Objective To explore the sigrificance of polymerase chain reaction (PCR) amplification of 16SrDNA with highly conserved sequences in the diagnosis of neonatal septicemia in comparison to blood culture and other nonspecific tests, including leukocyte count, platelet count, ratio of immature neutrophil to total number of neutrophil, Creactive protein and micro blood sedimentation. Methods The authors amplified bacterial DNA in blood specimens from 131 cases of suspected septicemia. Results There were 23 patients with definitive septicemia and 31 patients with clinical septicemia of the 131 suspected patients. Of the 131 cases, 56 were positive by PCR and the positive rate (43%) was significantly higher than that of blood culture (18%). Of 54 cases of septicemia, 48 were positive and 6 were negative by PCR; in 77 cases who were not diagnosed as septicemia, no 16SrDNA was amplified in 69 cases yet in the remaining 8 cases the PCR showed positive result. Of 23 cases of definitive septicemia, 22 cases were found positive. When blood culture was regarded as “gold standard”, the sensitivity of PCR was 96%. PCR amplification was not affected by antibiotics. No signal was observed when DNA from 30 controls was used as templates. Conclusion 16SrDNA PCR amplification, having high sensitivity and specificity, may become a reliable way for the etidogic diagnosis of neonatal septicemia when strict caution is taken to control contamination.