为探讨实验室常规鉴定手段对哈特草螺菌临床分离株的鉴定能力,分析案例患者血液中哈特草螺菌的感染来源,本文使用自动生化鉴定系统、基质辅助激光解吸电离飞行时间质谱(matrix-assisted laser desorption ionization-time of flight mass spectrometer,MALDI-TOF MS)、16S rRNA基因测序和RNA 聚合酶的β亚基(rpoB)基因测序对哈特草螺菌进行鉴定,并对患者多部位标本进行哈特草螺菌检测。结果显示,自动生化鉴定系统将哈特草螺菌错误识别为洋葱伯克霍尔德菌,MALDI-TOF MS和16S rRNA基因测序无法鉴别哈特草螺菌、aquaticum草螺菌或camelliae草螺菌,rpoB基因测序可以准确将其鉴定为哈特草螺菌;除血液外,仅在患者粪便中检出少量哈特草螺菌,血液和粪便来源的哈特草螺菌肠杆菌基因间重复共有序列聚合酶链反应(enterobacterial repetitive intergenic consensus polymerase chain reaction,ERIC-PCR)结果显示,两者的DNA带型一致,MALDI-TOF MS 核心图谱(main spectra projection,MSP)聚类分析显示两者位于同一节点,且distance level<50,其耐药表型亦相同,血液和粪便来源的哈特草螺菌高度同源。本研究展示了自动生化鉴定系统、MALDI-TOF MS、16S rRNA基因测序和rpoB基因测序对哈特草螺菌的鉴定水平,并证实了哈特草螺菌可通过污染食物,经胃肠道感染导致直肠腺癌术后化疗患者发生脓毒症。
In order to explore the ability of routine laboratory identification methods to identify clinical isolates of Herbaspirillum huttiense (H. huttiense), the source of infection of H. huttiense in the blood of this patient was analyzed. Automated biochemical identification system, matrix-assisted laser desorption ionization-time of flight mass spectrometer (MALDI-TOF MS), 16S rRNA gene sequencing and rpoB gene sequencing were used to identify H. huttiense, and the specimens from multiple parts of the patient were detected. The results showed that the automatic biochemical identification system misidentified H. huttiense as Burkholderia cepacia. MALDI-TOF MS and 16S rRNA gene sequencing were not able to distinguish H. huttiense from Herbaspirillum aquaticum and Herbaspirillum camelliae, while rpoB gene sequencing could accurately identify H. huttiense. In addition to the blood, only a small amount of H. huttiense was detected in the patient’s feces. The results of enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR) showed the same DNA band patterns of H. huttiense from blood and feces. MALDI-TOF MS main spectra projection(MSP)cluster analysis showed that they were located at the same node, and the distance level was under 50, with the same resistance phenotype. The blood and fecal origins of H. huttiense were highly homologous. This study demonstrated the performance of automated biochemical identification system, MALDI-TOF MS, 16S rRNA gene sequencing and rpoB gene sequencing for identification of H. huttiense, which confirmed that H. huttiense could infect gastrointestinal tract through contaminated food and cause sepsis in patients with postoperative chemotherapy for rectal adenocarcinoma.