Kuhl S J, Tang Y J, Navarro L, Gumerlock P H, Silva J
Department of Internal Medicine, School of Medicine, University of California, Davis, Sacramento.
Clin Infect Dis. 1993 Jun;16 Suppl 4:S234-8. doi: 10.1093/clinids/16.supplement_4.s234.
Toxigenic Clostridium difficile is the etiologic agent of pseudomembranous colitis. We have developed an assay system for the rapid direct detection of toxigenic C. difficile in human stool samples. After DNA extraction, polymerase chain reaction (PCR) amplification is undertaken with primers targeting specific sequences in the C. difficile 16S rRNA gene. Next, toxigenic strains of C. difficile are distinguished from nontoxigenic strains by PCR amplification of toxin A and/or B gene sequences. This study included 12 patients with C. difficile colitis, seven of whom had clinical relapses after discontinuation of vancomycin therapy. We detected toxigenic C. difficile in stools from four (57%) of these seven patients before relapse--at a time when no toxin B was detectable in stools and results of anaerobic culture were negative. The PCR assay is 100-fold more sensitive than anaerobic culture methods. The course of the infection in one patient (both during and after therapy) was monitored by the PCR technique. The multigene analysis approach permitted the detection of colonization with a nontoxigenic strain when this patient's relapses had cleared. This clinically applicable assay allows earlier detection of infection with toxigenic C. difficile. The result is more timely therapeutic intervention.
产毒艰难梭菌是伪膜性结肠炎的病原体。我们开发了一种检测系统，用于快速直接检测人类粪便样本中的产毒艰难梭菌。提取DNA后，使用针对艰难梭菌16S rRNA基因特定序列的引物进行聚合酶链反应（PCR）扩增。接下来，通过毒素A和/或B基因序列的PCR扩增，将产毒艰难梭菌菌株与非产毒菌株区分开来。本研究纳入了12例艰难梭菌结肠炎患者，其中7例在停用万古霉素治疗后出现临床复发。在这7例患者中的4例（57%）复发前的粪便中检测到了产毒艰难梭菌——此时粪便中检测不到毒素B，厌氧培养结果为阴性。PCR检测比厌氧培养方法灵敏100倍。通过PCR技术监测了1例患者感染的全过程（治疗期间和治疗后）。当该患者的复发症状消除时，多基因分析方法检测到了非产毒菌株的定植。这种临床适用的检测方法能够更早地检测出产毒艰难梭菌感染。其结果是能够更及时地进行治疗干预。
