Is Regular Probiotic Practice Safe for Management of Sepsis?

Gut Distribution, Impact Factor, and Action Mechanism of Bacteriocin-Producing Beneficial Microbes as Promising Antimicrobial Agents in Gastrointestinal Infection

Gastrointestinal (GI) infection by intestinal pathogens poses great threats to human health, and the therapeutic use of antibiotics has reached a bottleneck due to drug resistance. The developments of antimicrobial peptides produced by beneficial bacteria have drawn attention by virtue of effective, safe, and not prone to developing resistance. Though bacteriocin as antimicrobial agent in gut infection has been intensively investigated and reviewed, reviews on that of bacteriocin-producing beneficial microbes are very rare. It is important to explicitly state the prospect of bacteriocin-producing microbes in prevention of gastrointestinal infection towards their application in host. This review discusses the potential of gut as an appropriate resource for mining targeted bacteriocin-producing microbes. Then, host-related factors affecting the bacteriocin production and activity of bacteriocin-producing microbes in the gut are summarized. Accordingly, the multiple mechanisms (direct inhibition and indirect inhibition) behind the preventive effects of bacteriocin-producing microbes on gut infection are discussed. Finally, we propose several targeted strategies for the manipulation of bacteriocin-producing beneficial microbes to improve their performance in antimicrobial outcomes. We anticipate an upcoming emergence of developments and applications of bacteriocin-producing beneficial microbes as antimicrobial agent in gut infection induced by pathogenic bacteria.

The leaky gut and the gut microbiome in sepsis - targets in research and treatment

Both a leaky gut (a barrier defect of the intestinal surface) and gut dysbiosis (a change in the intestinal microbial population) are intrinsic to sepsis. While sepsis itself can cause dysbiosis, dysbiosis can worsen sepsis. The leaky gut syndrome refers to a status with which there is an increased intestinal permeability allowing the translocation of microbial molecules from the gut into the blood circulation. It is not just a symptom of gastrointestinal involvement, but also an underlying cause that develops independently, and its presence could be recognized by the detection, in blood, of lipopolysaccharides and (1→3)-β-D-glucan (major components of gut microbiota). Gut-dysbiosis is the consequence of a reduction in some bacterial species in the gut microbiome, as a consequence of intestinal mucosal immunity defect, caused by intestinal hypoperfusion, immune cell apoptosis, and a variety of enteric neuro-humoral-immunity responses. A reduction in bacteria that produce short-chain fatty acids could change the intestinal barriers, leading to the translocation of pathogen molecules, into the circulation where it causes systemic inflammation. Even gut fungi might be increased in human patients with sepsis, even though this has not been consistently observed in murine models of sepsis, probably because of the longer duration of sepsis and also antibiotic use in patients. The gut virobiome that partly consists of bacteriophages is also detectable in gut contents that might be different between sepsis and normal hosts. These alterations of gut dysbiosis altogether could be an interesting target for sepsis adjuvant therapies, e.g., by faecal transplantation or probiotic therapy. Here, current information on leaky gut and gut dysbiosis along with the potential biomarkers, new treatment strategies, and future research topics are mentioned.

Immunomodulatory Effects of Probiotics on COVID-19 Infection by Targeting the Gut–Lung Axis Microbial Cross-Talk

The ecosystem of the human gastrointestinal tract, named gut microbiota, represents the most thoroughly mapped ecosystem. Perturbations on bacterial populations cause dysbiosis, a condition correlated to a wide range of autoimmune, neurological, metabolic, cardiovascular, and respiratory diseases. The lungs have their flora, which are directly related to the gut flora via bidirectional communication allowing the transport of microbial metabolites and toxins produced by intestinal bacteria through the circulation and lymphatic system. This mutual microbial cross-talk communication called the gut–lung axis modulates the immune and inflammatory response to infections. COVID-19 causes dysbiosis, altered intestinal permeability, and bacterial translocation. Dysbiosis, through the gut–lung axis, promotes hyper-inflammation, exacerbates lung damage, and worsens clinical outcomes. Preclinical and clinical studies have shown that probiotics can regulate cytokine secretion, thus affecting both nonspecific and specific immunity. Probiotics act by blocking the virus from invading and proliferating in host cells, by stimulating the immune response, and by suppressing the activation of NLRP3 inflammasome. Herein, we reviewed the evidence from preclinical and clinical studies evaluating the effect of probiotics administration on the immune response to COVID-19 infection by targeting the gut–lung axis microbial cross-talk.

Effects of Probiotics and Lactoferrin on Necrotizing Enterocolitis in Preterm Infants

Background

Necrotizing enterocolitis (NEC) is a leading cause of morbidity and mortality in neonates. Despite intensive research, the etiology and pathophysiology of NEC is still obscure. Evidence from recent studies and meta-analyses showed a significant role of probiotics as a prophylactic measure in reducing NEC, sepsis, and mortality. However, obstacles against the generalization of the results still remain. The aim of the study was to evaluate the role of prophylactic administration of probiotics and lactoferrin in reducing the rate of NEC in preterm infants.

Methods

In this retrospective cohort study, all medical records of infants born with a birth weight of 1,500 g and less who were born between 2012 and 2017 were reviewed. The enrolled infants were divided into two groups: group 1 included infants born between January 2012 and August 2014, a period before probiotics were started in our unit, and group 2 included infants born between January 2014 and December 2017 after starting probiotics and lactoferrin. Multiple variables were collected including maternal data, neonatal data, and risk factors for NEC.

Results

Medical records of 284 infants who met our inclusion criteria were reviewed. Of the 284 infants, 134 were in group 1 and 150 infants were in group 2. There were no significant statistical differences between group 1 and group 2 in neonatal and maternal demographic data and clinical data. Of 134 infants who received probiotics and lactoferrin, 11 developed NEC, while 26 of the 150 infants in group 2 developed NEC, and the difference was statistically significant (p = 0.023).

Conclusion

Probiotics and lactoferrin given orally to very low birth weight preterm infants were associated with a decreased rate of NEC.