The microbiome and critical illness

Abstract

The central role of the microbiome in critical illness is supported by a half century of experimental and clinical study. The physiological effects of critical illness and the clinical interventions of intensive care substantially alter the microbiome. In turn, the microbiome predicts patients’ susceptibility to disease, and manipulation of the microbiome has prevented or modulated critical illness in animal models and clinical trials. This Review surveys the microbial ecology of critically ill patients, presents the facts and unanswered questions surrounding gut-derived sepsis, and explores the radically altered ecosystem of the injured alveolus. The revolution in culture-independent microbiology has provided the tools needed to target the microbiome rationally for the prevention and treatment of critical illness, holding great promise to improve the acute and chronic outcomes of the critically ill.

Readmissions for Recurrent Sepsis: New or Relapsed Infection?*

“…The local effects of sepsis, including both microbiome and anatomic disruption, may be contributing factors to recurrent infection at the same site. For example, in critical illness, hypoperfusion and subsequent reperfusion of the intestinal mucosal frequently causes bacterial translocation, and thus a risk factor for recurrent infection(28). Another potential risk factor that should be further investigated is the presence of underlying disease that may predispose patients to developing infection at the same site such as persistent nidus of infection, barrier to infection clearance, or prior indwelling catheters, intravenous lines or invasive procedures.…”

The immunopathology of sepsis and potential therapeutic targets

“…Critical illness and sepsis have a pronounced effect on the gut and lung microbiomes 73 . Conversely, dysbiosis in the gut has been linked to the subsequent hospitalization of patients with sepsis, which suggests an association between the composition of the gut microbiota and sepsis susceptibility 74 .…”

Focus on infection and sepsis 2017

“…A recent manuscript by Zakharkina et al found that duration of mechanical ventilation, but not antibiotic administration, was associated with changes in the respiratory microbiome [15]. Recent studies reported that despite previous evidence [16], highly heterogeneous patterns of intestinal microbiota existed in both septic and non-septic critically ill patients. This might shed light on our understanding of the conflicting results with the effect of probiotics on the incidence of VAP in critically ill patients.…”