Laboratory diagnosis of Clostridium difficile infection: Comparison of Techlab C. diff Quik Chek Complete, Xpert C. difficile, and multistep algorithmic approach.
BACKGROUND
Clostridium difficile is a major pathogen responsible for nosocomial infectious diarrhea. We explored optimal laboratory strategies for diagnosis of C. difficile infection (CDI) in our clinical settings, a 1400-bed tertiary care hospital.


METHODS
Using 191 fresh stool samples from adult patients, we evaluated the performance of Xpert C. difficile (Xpert CD), C. diff Quik Chek Complete (which simultaneously detects glutamate dehydrogenase [GDH] and C. difficile toxins [CDT]), toxigenic culture, and a two-step algorithm composed of GDH/CDT as a screening test and Xpert CD as a confirmatory test.


RESULTS
Clostridium difficile was detected in 35 samples (18.3%), and all isolates were toxigenic strains. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value of each assay for detecting CDI were as follows: Quik Chek Complete CDT (45.7%, 100%, 100%, 89.1%), Quik Chek Complete GDH (97.1%, 99.4%, 97.1%, 99.4%), Xpert CD (94.3%, 100%, 100%, 98.7%), and toxigenic culture (91.4%, 100%, 100%, 98.1%). A two-step algorithm performed identically with Xpert CD assay.


CONCLUSIONS
Our data showed that most C. difficile isolates from adult patients were toxigenic. We demonstrated that a two-step algorithm based on GDH/CDT assay followed by Xpert CD assay as a confirmatory test was rapid, reliable, and cost effective for diagnosis of CDI in an adult patient setting with high prevalence of toxigenic C. difficile.
Department of Laboratory Medicine, Gachon University Gil Medical Center, Incheon, Korea.
Ja Young
JY
Seo
Department of Laboratory Medicine, Gachon University Gil Medical Center, Incheon, Korea.
Ji Hun
JH
Jeong
Department of Laboratory Medicine, Gachon University Gil Medical Center, Incheon, Korea.
Kyung Hee
KH
Kim
Department of Laboratory Medicine, Gachon University Gil Medical Center, Incheon, Korea.
Jeong-Yeal
JY
Ahn
Department of Laboratory Medicine, Gachon University Gil Medical Center, Incheon, Korea.
Pil-Whan
PW
Park
Department of Laboratory Medicine, Gachon University Gil Medical Center, Incheon, Korea.
Yiel-Hea
YH
Seo
D000368:Aged; D015373:Bacterial Typing Techniques / Q000379:methods* / Q000706:statistics & numerical data*; D016360:Clostridioides difficile / Q000302:isolation & purification; D003015:Clostridium Infections / Q000175:diagnosis*; D005243:Feces / Q000382:microbiology; D006801:Humans; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies

Clostridium difficile
; adult; diagnosis; glutamate dehydrogenase; multistep algorithm; tertiary care hospital