Abstract
BACKGROUND/AIMS: The clinical characteristics of Clostridioides difficile infection (CDI) in patients within the Asia-Pacific region who test positive on the nucleic acid amplification test (NAAT) and negative on the toxin enzyme immunoassay (EIA, hereafter referred to as "Toxin") are unclear. We evaluated the clinical significance and associated factors of NAAT+/Toxinpatients whose diagnosis of CDI was confirmed by toxigenic C. difficile culture. METHODS: This retrospective cohort study enrolled adult patients admitted to Seoul St. Mary's Hospital between January 2015 and December 2015 with a diagnosis of active CDI. RESULTS: In total, 3,311 stool samples were subjected to C. difficile culture, NAAT, and toxin EIA. Among them, 298 culture- positive patients fulfilled the criteria for CDI, and 3 NAAT-/Toxin- patients were excluded. The risk factors for a negative EIA and positive NAAT and culture results were evaluated in 295 patients. Among them, 128 patients were Toxin- and 167 were Toxin+. No clinical or laboratory parameters (fever, white blood cell count of < 1,000/mm3, eosinophils, C-reactive protein, creatinine, or albumin) differed significantly between NAAT+/Toxin+ and NAAT+/Toxin- patients. In addition, the clinical outcomes did not differ between the two groups. In the multivariable analysis, previous use of antibiotics was inversely associated with negative EIA results, whereas high-dose corticosteroid use was positively associated. CONCLUSION: Clinical outcomes related to CDI are not different between NAAT+/Toxin+ and NAAT+/Toxin- patients, emphasizing the need for individual clinical evaluation.