Candida and the Gram-Positive Trio: Testing the Vibe in the Icu Patient Microbiome Using Structural Equation Modelling of Literature Derived Data.

Background: Whether Candida interacts with Gram-positive bacteria to enhance their invasive potential from the microbiome of ICU patients remains unclear. Several effective interventions to prevent ICU acquired infection would be expected to variably impact Candida colonization.MethodsFour candidate generalized structural equation models (GSEM), using Staphylococcus aureus, coagulase negative Staphylococci (CNS) and Enterococci colonization as latent variables, were confronted with blood culture and respiratory tract isolate data derived from > 400 groups from >250 infection prevention studies.ResultsIntroducing interaction terms between Candida colonization and each of Staphylococcus aureus (coefficient +0.34; 95% confidence interval 0.19 to 0.48) and Enterococcal (+0.55; 0.23 to 0.86) colonization (all as latent variables) improved the fit for each model. The magnitude and significance level of the interaction terms were similar to the positive associations between exposure to topical antibiotic prophylaxis (TAP) on Enterococcal (+0.52; 0.06 to 1.0) versus the negative association with Staphylococcus aureus (-0.42; -0.66 to -0.17) colonization.ConclusionsGSEM modelling of published ICU infection prevention data implies interactions between Candida and Gram-positive bacteria in the human microbiome. This interaction might also account for the paradoxically high incidences among studies of TAP in ICU patients.