Structural equation modeling the ICU patient microbiome and risk of bacteremia

Whether Candida interacts with Gram-positive bacteria to enhance their invasive potential from the microbiome leading to infection within intensive care unit (ICU) patients remains unclear. These infections arise from the colonizing flora, but quantifying microbial colonization in patients is not simple. Using published ICU infection prevention data, one can model the interaction between Candida and Gram-positive bacteria (at the level of the ICU) using generalized structural equation models (GSEM). In these models, colonization is a latent variable defined by the proportion of patients with respiratory tract or blood stream infections. The various ICU infection prevention interventions (as studied within more than 250 publications) variously impact colonization with Candida and Gram-positive bacteria, which are measured as latent variables within the GSEM. The models provide support to interactions occurring between Candida and Gram-positive bacteria, contributing to bacteremia and pneumonia with these microbes within ICU patients. Similar GSEM modeling likewise implicates interactions between Candida and Gram-negative bacteria contributing to bacteremia.