The Role of Dysbiosis in Critically Ill Patients With COVID-19 and Acute Respiratory Distress Syndrome

Abstract

In late December 2019, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) quickly spread worldwide, and the syndrome it causes, coronavirus disease 2019 (COVID-19), has reached pandemic proportions. Around 30% of patients with COVID-19 experience severe respiratory distress and are admitted to the intensive care unit for comprehensive critical care. Patients with COVID-19 often present an enhanced immune response with a hyperinflammatory state characterized by a “cytokine storm,” which may reflect changes in the microbiota composition. Moreover, the evolution to acute respiratory distress syndrome (ARDS) may increase the severity of COVID-19 and related dysbiosis. During critical illness, the multitude of therapies administered, including antibiotics, sedatives, analgesics, body position, invasive mechanical ventilation, and nutritional support, may enhance the inflammatory response and alter the balance of patients' microbiota. This status of dysbiosis may lead to hyper vulnerability in patients and an inappropriate response to critical circumstances. In this context, the aim of our narrative review is to provide an overview of possible interaction between patients' microbiota dysbiosis and clinical status of severe COVID-19 with ARDS, taking into consideration the characteristic hyperinflammatory state of this condition, respiratory distress, and provide an overview on possible nutritional strategies for critically ill patients with COVID-19-ARDS.

Diagnostic, Prognostic, and Therapeutic Roles of Gut Microbiota in COVID-19: A Comprehensive Systematic Review

“…The gut and lung microbiome are closely related in health or disease conditions (Dickson and Huffnagle, 2015;Enaud et al, 2020;Ahmadi Badi et al, 2021). SARS-CoV-2 may cause a dysbiosis in the lung microbiota to increase the population of inflammatory bacteria such as Klebsiella oxytoca and Rothia mucilaginosa which is associated with acute respiratory distress syndrome (Aktaşand Aslim, 2020;Han et al, 2020;van der Lelie and Taghavi, 2020;Battaglini et al, 2021;Chattopadhyay and Shankar, 2021). The high levels of inflammatory cytokine productions during SARS-CoV-2 invasion interfere with gut mucosal integrity and increasing risk of bacterial disposition to the bloodstream (Chattopadhyay and Shankar, 2021;Prasad et al, 2021).…”

Interactions between the Gut Microbiome, Lung Conditions, and Coronary Heart Disease and How Probiotics Affect These

“…Immune modulation of the gut microbiome in response to an infection of the respiratory tract is also a possibility. Many of the symptoms related to COVID-19 are due to an overactive immune response, resulting in a potentially lethal cytokine storm and acute respiratory distress syndrome (ARDS) [118]. Interestingly, bacteria associated with inflammation, such as Blautia and Ruminococcus species, were more abundant in the gut microbiota of symptomatic COVID-19 patients, as reviewed by others [119].…”

“…It would be naive to think that probiotics can completely prevent SARS-CoV-2 infection or COVID-19 symptoms, but since a healthy gut microbiome has obvious health benefits to multiple organs, probiotics have been proposed as one of the multiple strategies to ameliorate SARS-CoV-2 infections [6,[114][115][116][117][118].…”

COVID-19-Associated Candidiasis: Possible Patho-Mechanism, Predisposing Factors, and Prevention Strategies

“…to outcompete other organisms to colonize and disseminate [ 19 , 55 , 61 , 70 ]. Although the precise causes of dysbiosis are unknown, it may be caused by numerous other factors as well, such as the prescription of analgesics and the onset of lymphopenia during COVID-19 [ 71 ]. The level of dysbiosis may also differ depending on age, BMI, presence of comorbidities, etc.…”

“…Subsequently, the already weakened immune system is further suppressed by drugs prescribed during COVID-19 infection—this may facilitate Candida spp. to manipulate and evade the host immune system [ 71 , 73 , 80 ]. COVID-19 patients with poor clinical outcomes or severe cases were found to have elevated levels of blood lactate [ 81 ] and increased levels of acid in blood and body tissues, i.e., acidosis [ 82 ].…”