Nakasone Isamu, Shiohira Chika M, Yamane Nobuhisa
Clinical Laboratories, University Hospital of the Ryukyus, 207 Uehara, Nishihara, Nakagami, Okinawa 903-0215, Japan.
Rinsho Biseibutshu Jinsoku Shindan Kenkyukai Shi. 2007;18(2):109-16.
The TOX A/B QUIK CHEK "NISSUI" which detects both toxin A (TcdA) and toxin B (TcdB) of Clostridium difficile in stool specimens through immunochromatography was first approved to be released in Japan, and we evaluated its accuracy. In the evaluation, the TOX A/B QUIK CHEK "NISSUI" could correctly detect TcdA and TcdB in solution and in stool specimens spiked with culture broth of TcdA and/or TcdB-producing isolates of C. difficile. The minimum detectable concentrations for TcdA and TcdB were determined to be < or =0.32 ng/ml and < or =0.63 ng/ml, respectively. The TOX A/B QUIK CHEK "NISSUI" gave the consistent results with the colon-endoscopic diagnosis, that is, all the 10 stool specimens from the patients with pseudomembranous colitis were read as being positive, but negative for five patients without any C. difficile-associated disease (CDAD). Of 10 positive stool specimens, one was read as being negative by the commercially available test reagents that can detect only TcdA. In clinical evaluation, a total of 240 stool specimens were tested. Of these, the TOX A/B QUIK CHEK "NISSUI" gave 19 positive results, and TcdA and/or TcdB-producing strains of C. difficile were successfully isolated from all the positive stool specimens, except one. Whereas, of 221 negative stool specimens, 28 isolates of C. difficile were recovered and 11 isolates were identified as TcdA and/or TcdB-producing strains. With these results, it can be concluded that the TOX A/B QUIK CHEK "NISSUI" can correctly detect both TcdA and TcdB of C. difficile, and should be promptly applied to clinical microbiology laboratory to make a definite diagnosis of CDAD, particularly for the CDAD caused by the TcdA-negative but TcdB-positive mutant strains.
通过免疫色谱法在粪便标本中检测艰难梭菌毒素A（TcdA）和毒素B（TcdB）的TOX A/B QUIK CHEK “NISSUI”首次在日本获批上市，我们对其准确性进行了评估。在评估中，TOX A/B QUIK CHEK “NISSUI”能够正确检测溶液中以及接种了产TcdA和/或TcdB的艰难梭菌分离株培养液的粪便标本中的TcdA和TcdB。TcdA和TcdB的最低可检测浓度分别确定为≤0.32 ng/ml和≤0.63 ng/ml。TOX A/B QUIK CHEK “NISSUI”与结肠镜诊断结果一致，即10例伪膜性结肠炎患者的粪便标本均检测为阳性，但5例无艰难梭菌相关疾病（CDAD）的患者粪便标本检测为阴性。在10份阳性粪便标本中，有1份被仅能检测TcdA的市售检测试剂误判为阴性。在临床评估中，共检测了240份粪便标本。其中，TOX A/B QUIK CHEK “NISSUI”检测出19份阳性结果，除1份外，所有阳性粪便标本均成功分离出产TcdA和/或TcdB的艰难梭菌菌株。而在221份阴性粪便标本中，分离出28株艰难梭菌，其中11株被鉴定为产TcdA和/或TcdB的菌株。基于这些结果，可以得出结论，TOX A/B QUIK CHEK “NISSUI”能够正确检测艰难梭菌的TcdA和TcdB，应迅速应用于临床微生物实验室以明确诊断CDAD，特别是对于由TcdA阴性但TcdB阳性突变菌株引起的CDAD。
