Detection of Candida DNA in peritoneal fluids by PCR assay optimizing the diagnosis and treatment for intra-abdominal candidiasis in high-risk ICU patients: A prospective cohort study

Abstract Background: Intra-abdominal candidiasis (IAC) is the predominant type of invasive candidiasis with high mortality in critically ill surgical patients. The high mortality rate may be related to the difficulty of early diagnosis. This study aimed to investigate whether the polymerase chain reaction (PCR) assay for detecting Candida DNA in peritoneal fluids (PF) is useful in diagnosing and antifungal treatment of IAC in high-risk patients in the ICU. Methods: A prospective single-center cohort study of surgical patients at high risk for IAC was conducted in the ICU. PF was collected from the abdominal drainage tubes (within 24 h) or by percutaneous puncture. Direct PF smear microscopy, PF culture, blood culture, and serum (1-3)-β-D-glucan were performed in all patients. For Candida PCR assay, the ITS1/ITS4 primers that targeted the ITS1-5.8s-ITS2 regions were used for PCR, and sequencing analysis was used to identify the pathogen at the species level. IAC was defined according to the 2013 European consensus criteria. Results: Among 83 patients at high risk for IAC, the IAC criteria were present in 17 (20.5%). The sensitivity and specificity of the Candida PCR assay were 64.7% and 89.4%, respectively, and the area under the receiver operating characteristic curve was 0.77 (95% CI: 0.63–0.91). In this cohort, the positive predictive value and negative predictive value for Candida PCR assay were 90.8% (95% CI: 80.3%–96.2%) and 61.1% (95% CI: 36.1%–81.7%), respectively. Diagnostic consistency was moderate (kappa 0.529, P < 0.001) according to the 2013 European consensus criteria. Assuming that positive Candida PCR in PF was the diagnostic criterion of IAC, the incidence of IAC could increase from 20.5% to 28.9% (P < 0.001), and the proportion of antifungal initial target therapies could increase from 11.3% to 32.1% (P < 0.001). Conclusions: Detection of Candida DNA in PF using PCR can be considered a supplement to existing diagnostic tools. This may optimize the diagnosis and antifungal treatment of IAC in high-risk surgical patients in the ICU.Trial registration: The study protocol was registered in the China Clinical Trial Registration Center (CHiCTR190022695). Registered 22 April 2019 (retrospectively registered).