Comparison of VIDAS CDAB and CDA immunoassay for the detection of Clostridium difficile in a tcdA- tcdB+ C. difficile prevalent area.
Enzyme immunoassays for TcdA and/or TcdB are widely used for diagnosis of C. difficile infection. This study compared the performance of the new VIDAS C. difficile Toxin A & B assay (CDAB) with that of the existing VIDAS C. difficile Toxin A II assay (CDA) in a tcdA(-)tcdB(+) prevalent area. A total of 555 fecal samples were cultured and tested using CDAB and CDA. C. difficile was isolated in 150 samples and the concordance rate was 81.8% (454/555) between CDAB and CDA. PCR assays for tcdA and/or tcdB were used as a confirmatory test on C. difficile strains recovered from culture positive cases (n=150) and on fecal specimens in culture negative/CDAB positive or equivocal cases (n=27). The number of tcdA(+)tcdB(+), tcdA(-)tcdB(+), and tcdA(-)tcdB(-) strains on culture positive isolates (n=150) were 75 (50.0%), 41 (27.3%), and 34 (22.7%), respectively. PCR assays for tcdB gene alone in stool specimens (n=27) showed positivity in five cases. The sensitivity of VIDAS CDAB was higher than that of VIDAS CDA (65.3% vs. 29.8%), by more than 2-fold. The specificity of CDAB was almost the same as CDA (93.8% vs. 94.5%). Toxigenic culture of C. difficile isolates in culture positive/VIDAS CDAB negative cases (n=62) additionally detected 22 VIDAS CDAB positive and 9 VIDAS CDAB equivocal cases. The VIDAS CDAB assay detects more tcdA(+)tcdB(+) strains (60% vs. 45.3%) and tcdA(-)tcdB(+) strains (70.7% vs. 0%) compared with VIDAS CDA.
Shin
Bo-Moon
BM
Department of Laboratory Medicine, Sanggye Paik Hospital, Inje University, Seoul, 139 707, Korea. bmshin@unitel.co.kr
Lee
Eun-Joo
EJ
Kuak
Eun-Young
EY
Yoo
Soo Jin
SJ
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001426:Bacterial Proteins / Q000032:analysis* / Q000235:genetics; D001427:Bacterial Toxins / Q000032:analysis* / Q000235:genetics; D002648:Child; D016360:Clostridioides difficile / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D003470:Culture Media; D004269:DNA, Bacterial / Q000032:analysis; D004761:Enterocolitis, Pseudomembranous / Q000175:diagnosis* / Q000453:epidemiology / Q000382:microbiology; D004768:Enterotoxins / Q000032:analysis* / Q000235:genetics; D005243:Feces / Q000737:chemistry / Q000382:microbiology; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques / Q000379:methods*; D007723:Korea / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D015995:Prevalence; D011933:Reagent Kits, Diagnostic; D012680:Sensitivity and Specificity; D055815:Young Adult
D001426:Bacterial Proteins; D001427:Bacterial Toxins; D003470:Culture Media; D004269:DNA, Bacterial; D004768:Enterotoxins; D011933:Reagent Kits, Diagnostic; C041348:tcdA protein, Clostridium difficile; C031815:toxB protein, Clostridium difficile