Clostridium difficile 독소 A 및 독소 B 검출을 위한 효소면역법의 비교 = Comparison of Two Enzyme Immunoassay for Detection of Clostridium difficile Toxin A and Toxin B

다국어 초록 (Multilingual Abstract)

Background : Enzyme immunoassay (EIA) capable of detecting both toxin A and toxin B is strongly recommended for the diagnosis of Clostridium difficile associated disease. Therefore, we evaluated two different EIAs for the detection of C. difficile toxin A/B.
Methods : For a total of 228 stool specimens we performed bacteriologic cultures for C. difficile and examined for toxin A and toxin B using enzyme linked fluorescent immunoassay (ELFA; VIDAS CDAB, Bio-Merieux sa, France) and ELISA (C.DIFFICILE TOX A/B II, TECHLAB, USA). We also performed PCR assays for toxin A and B genes in 117 C. difficile isolates that grew from the stool cultures and compared the results with those obtained with the two different EIAs.
Results : The concordance rate between ELFA and ELISA was 85.5% (195/228). Using the culture and PCR results as the standard, the sensitivity/specificity of the ELFA and ELISA were 65.0%/72.1%
and 71.8%/70.3%, and for positive/negative predictive values were 78.4%/69.6% and 71.8%/70.3%, respectively (P value >0.05). No differences were observed between the results of ELFA and ELISA with toxin A- toxin B+ strains of C. difficile.
Conclusions : The sensitivity of the ELISA was slightly higher than that of ELFA for toxin A and toxin B, but the specificity and positive predictive value of the ELFA were rather higher than those of the ELISA, although no statistical differences were observed. A bacteriologic culture and PCR assay for
toxin genes are recommended in case the both EIAs are negative.

국문 초록 (Abstract)

서론 : Clostridium difficile 연관 질환을 진단하기 위해서는
독소 A-, 독소 B+ C. difficile을 포함하여 진단할 수 있는 독소
A/B 효소면역법이 요구된다. 이에 C. difficile 독소 A 및 B를
동시에 검출하는 두 종류의 효소면역법을 비교하여 진단적 의
의를 평가하고자 하였다.
재료 및 방법 : C. diffcile 배양 검사가 의뢰되었던 228예의
설사변을 대상으로 혐기성 배양을 시행하였으며, 같은 검체로
enzyme linked fluorescent immunoassay (ELFA)법 (VIDAS
CDAB, bio-Merieux sa, France)과 ELISA법(C. DIFFICILE
TOX A II, TECHLAB, USA)을 이용한 독소 A/B 검사를 시행
하였다. 배양에서 분리된 C. difficile 117 균주를 대상으로 독소
A 및 독소 B 유전자에 대한 PCR 검사를 시행하고 그 결과를 두
종류의 효소면역법 결과와 비교하였다.
결과 : ELFA와 ELISA법 간의 결과 일치율은 85.5% (195/
228)였다. 독소 A 및 독소 B 유전자 PCR 및 배양을 기준으로
한 ELFA와 ELISA의 민감도 및 특이도는 각각 65.0%/72.1%
및 71.8%/70.3%였다. 양성 및 음성 예측률은 ELFA법이 78.4%/
69.6%, ELISA법이 71.8%/70.3%이었다(P value >0.05). ELFA
와 ELISA법에 의한 A-B+ C. difficile의 독소 검출은 차이가
없었다.
결론 : 독소 A 및 독소 B에 대한 검출 민감도는 ELISA법이
다소 높았으며, 특이도 및 양성 예측률은 ELFA법이 높았지만,
통계학적인 차이는 없었다. 그러나 효소면역법 음성인 경우 배
양 및 PCR 검사를 시행할 필요가 있다고 사료된다.

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