Candida–Acinetobacter–Pseudomonas Interaction Modelled within 286 ICU Infection Prevention Studies

Abstract

Background: Whether Candida interacts to enhance the invasive potential of Acinetobacter and Pseudomonas bacteria cannot be resolved within individual studies. There are several anti-septic, antibiotic, anti-fungal, and non-decontamination-based interventions to prevent ICU acquired infection. These effective prevention interventions would be expected to variably impact Candida colonization. The collective observations within control and intervention groups from numerous ICU infection prevention studies simulates a multi-centre natural experiment with which to evaluate Candida, Acinetobacter and Pseudomonas interaction (CAPI). Methods: Eight Candidate-generalized structural equation models (GSEM), with Candida, Pseudomonas and Acinetobacter colonization as latent variables, were confronted with blood culture and respiratory tract isolate data derived from >400 groups derived from 286 infection prevention studies. Results: Introducing an interaction term between Candida colonization and each of Pseudomonas and Acinetobacter colonization improved model fit in each case. The size of the coefficients (and 95% confidence intervals) for these interaction terms in the optimal Pseudomonas (+0.33; 0.22 to 0.45) and Acinetobacter models (+0.32; 0.01 to 0.5) were similar to each other and similar in magnitude, but contrary in direction, to the coefficient for exposure to topical antibiotic prophylaxis (TAP) on Pseudomonas colonization (−0.45; −0.71 to −0.2). The coefficient for exposure to topical antibiotic prophylaxis on Acinetobacter colonization was not significant. Conclusions: GSEM modelling of published ICU infection prevention data supports the CAPI concept. The CAPI model could account for some paradoxically high Acinetobacter and Pseudomonas infection incidences, most apparent among the concurrent control groups of TAP studies.

Structural equation modelling the relationship between anti-fungal prophylaxis and Pseudomonas bacteremia in ICU patients

“…The impact of anti-fungal prophylaxis on Pseudomonas colonization and infection is the only bacterial species examined here. However, other bacterial species, such as Acinetobacter warrant examination given the observed paradoxical incidences that occur in association within studies of topical antibiotic prophylaxis [ 39 , 40 ].…”

Selective digestive decontamination, a seemingly effective regimen with individual benefit or a flawed concept with population harm?

“…Whether rebound occurs within the intestinal ‘resistome’, which includes non-culturable flora, and the broader question of consequences for antibiotic resistance and even for bacteria which exhibit antibiotic dependency, are areas of active investigation [ 46 , 47 ]. Likewise, Candida interacting with bacteria within the microbiome might promote invasive bacterial infection from higher Candida colonization resulting from TAP [ 49 ].…”

“…Supportive data are available in the author’s cited publications [ 16 , 24 – 27 , 29 , 32 – 37 , 49 ].…”

Candida and the Gram-positive trio: testing the vibe in the ICU patient microbiome using structural equation modelling of literature derived data

“…Moreover, quantifying the impact of the various interventions on not only the presence but also the biological activity of microbial colonization within the microbiome is not simple. Structural equation modelling of literature derived data offers a novel approach [ 11 – 15 ].…”