16SrRNA基因PCR加基因芯片杂交快速诊断新生儿败血症

目的　探讨新生儿败血症的快速诊断方法。方法　 (1)以 16SrRNA基因为靶序列 ,设计引物及寡核苷酸探针 ;将探针固定在特制的玻片上制作成基因芯片 ;(2 )对临床疑为细菌感染的 2 85例新生儿抽取静脉血分别做血培养和细菌 16SrRNA基因检测 :于血标本及脑脊液中抽提DNA后采用聚合酶链反应 (PCR)扩增 ,将扩增产物加样在基因芯片上杂交后进行激光扫描及读片。结果(1)PCR检测阳性率 5 96 % (17/2 85 )明显高于血培养的 2 81% (8/2 85 ) ,差异有显著意义 (P <0 0 1)。若以确诊败血症作为对照 ,PCR的诊断敏感性为 10 0 % ,特异性为 96 75 % ,正确诊断指数为 0 96 8。(2 )对 17份PCR阳性标本进一步做基因芯片杂交 ,结果通用探针均阳性 ,其中G 探针阳性 12份、G-探针阳性 5份 ;8份PCR和血培养均阳性的标本 ,基因芯片杂交探针阳性菌株与血培养细菌阳性结果完全一致。结论　基因芯片杂交技术检测临床标本中 16SrRNA基因能快速诊断新生儿败血症 ,除较血培养等方法有更好的敏感性和特异性外 ,还能快速明确系何种病原菌感染 ,因此有较大的推广及应用价值

Rapid diagosis of neonatal sepsis by 16SrRNA genes PCR amplification and genechip hybridization

Objective To explore a method for rapid diagnosis of sepsis in newborn infants. Methods (1) The primers and oligonucleotide probes were designed and synthesized based on the sequences of bacterial 16SrRNA gene. The gene chip was prepared through the probes printed onto special glass slides. The gene chip included 18 special probes: universal probe 1, universal probe 2, Gram positive bacterial probe, Gram negative bacterial probe 1, Gram negative bacterial probe 2, Staphylococcus aureus, coagulase negative staphylococcus (CoNS) 1, CoNS 2, Escherichia coli, Hemophilus influenzae, Listeria monocytogenes, Streptococcus pneumoniae, Streptococcus agalactiae, Bacteroides fragilis, Bacillus, Meningococcus, Corynebacterium, Propionibacterium;(2) Blood specimens from 285 cases of suspected septicemia were cultured and bacterial 16S rRNA gene was detected separately; DNA isolated from blood specimens and cerebrospinal fluid was amplified by PCR, and PCR products were hybridized with the probes on the gene chips. Hybridization results were scanned and read by laser-scanner. Results (1) Of the 285 cases, 17 were positive by PCR and the positive rate (5.96%) was significantly higher than that of blood culture (2.81%)(P<0.01). When blood culture was taken as control, the sensitivity of PCR was 100% and Specificity was 96.75%, the index of accurate diagnosis was 0.968. (2) The 17 specimens which showed positive results by PCR were further hybridized on the gene chip. All were positive by universal probes. Among all of them, 5 were positive by E. coli probe; 4 were positive by Staphylococcus epidermidis; two were positive by Bacillus and Propionibacterium probes, separately; 4 were positive by CoNS. The 8 specimens which showed positive results by both PCR and blood culture, the result of gene chip hybridization coincided with the result of blood culture. Conclusion Detection of the bacterial 16SrRNA genes in clinical specimens by gene chip hybridization technology can diagnose neonatal septicemia rapidly. This method has higher sensitivity and specificity than blood culture or other methods and can provide a rapid way for the etiological diagnosis of neonatal septicemia. Therefore the genechip method may be valuable and practical in early diagnosis of neonatal septicemia.