GeneXpert实时荧光定量PCR在诊断艰难梭菌感染中的临床应用

目的评价Gene Xpert实时荧光定量PCR法在诊断艰难梭菌感染中的应用价值。方法收集住院腹泻患者非重复粪便标本296份,同时进行Gene Xpert试验和产毒素培养(toxigenic culture,TC)。TC包括厌氧培养、菌株基质辅助激光解吸电离飞行时间质谱(MALDI-TOF MS)鉴定、PCR扩增艰难梭菌毒素基因。以TC结果为参考,评价Gene Xpert试验的敏感性、特异性、阳性预测值、阴性预测值,并评价Gene Xpert试验和TC 2种方法结果的一致性。结果 Gene Xpert试验的敏感性、特异性、阳性预测值和阴性预测值分别为98.5%、92.6%、91.7%和98.7%。Gene Xpert试验与TC一致性好(Kappa=0.905)。Gene Xpert试验报告2株RT027型高毒力菌株,经核糖体分型确证为RT027型艰难梭菌。结论 Gene Xpert实时荧光定量PCR可快速、准确检测粪便标本中的艰难梭菌毒素基因,且可报告高毒力RT027型菌株,具有重要的临床应用价值。

Clinical application of GeneXpert real-time fluorescence quantitation PCR in the diagnosis of Clostridium difficile infection

Objective To evaluate the application value of Gene Xpert real-time fluorescence quantitation PCR( Gene Xpert PCR) in the diagnosis of Clostridium difficile infection. Methods A total of 296 unrepeated stool specimens were collected from the diarrhea inpatients,and toxigenic culture( TC) and Gene Xpert PCR were performed,respectively. For TC,after anaerobic culture,bacterial clones were identified by the matrix-assisted laser desorption/ionization time of flight mass spectrometry( MALDI-TOF MS) and the toxin genes of Clostridium difficile were detected by PCR. Taking TC results as a reference,the sensitivity,specificity,positive predictive value and negative predictive value of Gene Xpert PCR and the consistency of the results between Gene Xpert PCR and TC were evaluaed. Results The sensitivity,specificity,positive predictive value and negative predictive value of Gene Xpert PCR were 98.5%,92.6%,91.7% and 98. 7%,respectively,and there was good consistency between TC and Gene Xpert PCR( Kappa = 0. 905). Two strains of RT027 with high virulence were detected by Gene Xpert PCR,and were confirmed as RT027 type Clostridium difficile by Ribotyping. Conclusion Gene Xpert real-time fluorescence quantitation PCR is able to detect the toxin genes of Clostridium difficile in stool specimens rapidly and accurately,and able to identify the RT027 strains with high virulence,which has important clinical application value.