She Rosemary C, Durrant Robert J, Petti Cathy A
Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT, USA.
Am J Clin Pathol. 2009 Jan;131(1):81-4. doi: 10.1309/AJCPMM2E7VSPHNPG.
Stool culture for Clostridium difficile, while necessary for strain typing and antimicrobial surveillance, cannot determine toxin production. We prospectively tested in triplicate 91 C difficile cultured isolates for toxin production by 2 enzyme immunoassays (EIAs) (Meridian Premier Toxins A&B, Meridian Bioscience, Cincinnati, OH; and TechLab Tox A/B II, TechLab, Blacksburg, VA) and cytotoxin neutralization bioassay (CTN). By CTN, 88% (80/91) were toxigenic. Reproducibility was 93% (85/91) for CTN, 80% (73/91) for Meridian EIA, and 79% (72/91) for TechLab EIA. Compared with CTN, sensitivities were 87.1% and 89.2% for the Meridian and TechLab EIAs, respectively. In an additional 115 stool specimens, CTN detected toxin more frequently from cultured isolates (96/115) than stool (84/115). For C difficile toxin detection from isolates, EIA was less reproducible than CTN. EIA methods can be falsely negative in 10% to 12% of isolates, and these should be tested by CTN or polymerase chain reaction. When positive, EIA is fast and reliable for detecting C difficile toxin from culture.
艰难梭菌的粪便培养对于菌株分型和抗菌药物监测是必要的，但无法确定毒素产生情况。我们对91株艰难梭菌培养分离株进行了一式三份的前瞻性检测，通过2种酶免疫测定法（EIAs）（Meridian Premier毒素A&B，Meridian生物科学公司，俄亥俄州辛辛那提市；以及TechLab毒素A/B II，TechLab公司，弗吉尼亚州布莱克斯堡）和细胞毒素中和生物测定法（CTN）检测毒素产生情况。通过CTN检测，88%（80/91）的分离株产毒。CTN的重复性为93%（85/91），Meridian EIA为80%（73/91），TechLab EIA为79%（72/91）。与CTN相比，Meridian EIA和TechLab EIA的灵敏度分别为87.1%和89.2%。在另外115份粪便标本中，CTN从培养分离株中检测到毒素的频率（96/115）高于粪便（84/115）。对于从分离株中检测艰难梭菌毒素，EIA的重复性低于CTN。EIA方法在10%至12%的分离株中可能出现假阴性，这些分离株应通过CTN或聚合酶链反应进行检测。当结果为阳性时，EIA对于从培养物中检测艰难梭菌毒素快速且可靠。
