Can probiotics be an alternative to chlorhexidine for oral care in the mechanically ventilated patient? A multicentre, prospective, randomised controlled open trial

A Review of Chlorhexidine Oral Care in Patients Receiving Mechanical Ventilation

BACKGROUND

Chlorhexidine gluconate has been considered the criterion standard of oral care for patients receiving mechanical ventilation because of its ability to reduce the incidence of ventilator-associated events. Optimal concentrations and frequencies remain unclear, as do adverse events related to mortality in various intensive care unit populations.

OBJECTIVE

To examine the current evidence for the efficacy of chlorhexidine gluconate in reducing the incidence of ventilator-associated events, mortality, intensive care unit length of stay, and duration of mechanical ventilation in patients receiving ventilator support.

METHODS

In this integrative review, CINAHL (Cumulative Index to Nursing and Allied Health Literature), MEDLINE, and Health Source: Nursing/Academic Edition were searched using terms related to mechanical ventilation and chlorhexidine gluconate oral care with dates ranging from 2012 to 2023.

RESULTS

Seventeen articles were included in this review: 8 systematic reviews, 8 randomized clinical trials (3 of which were not included in any systematic review), and 1 quasi-experimental study. Chlorhexidine gluconate oral care was associated with a reduced incidence of ventilator-associated events, but efficacy depended on concentration and frequency of administration. With stratification by intensive care unit population type, a nonsignificant trend toward increased mortality was found among non-cardiac surgical patients who received this care.

CONCLUSION

The evidence regarding the efficacy of chlorhexidine gluconate oral care in reducing ventilator-associated events in specific intensive care unit populations is contradictory. Recently published guidelines recommend de-implementation of chlorhexidine gluconate oral care in all patients receiving mechanical ventilation. Such care may be beneficial only in the cardiac surgical population.

Novel Synergistic Probiotic Intervention: Transcriptomic and Metabolomic Analysis Reveals Ameliorative Effects on Immunity, Gut Barrier, and Metabolism of Mice during Salmonella typhimurium Infection

Salmonella typhimurium (S. typhimurium), a prevalent cause of foodborne infection, induces significant changes in the host transcriptome and metabolome. The lack of therapeutics with minimal or no side effects prompts the scientific community to explore alternative therapies. This study investigates the therapeutic potential of a probiotic mixture comprising Lactobacillus acidophilus (L. acidophilus 1.3251) and Lactobacillus plantarum (L. plantarum 9513) against S. typhimurium, utilizing transcriptome and metabolomic analyses, a novel approach that has not been previously documented. Twenty-four SPF-BALB/c mice were divided into four groups: control negative group (CNG); positive control group (CPG); probiotic-supplemented non-challenged group (LAPG); and probiotic-supplemented Salmonella-challenged group (LAPST). An RNA-sequencing analysis of small intestinal (ileum) tissue revealed 2907 upregulated and 394 downregulated DEGs in the LAPST vs. CPG group. A functional analysis of DEGs highlighted their significantly altered gene ontology (GO) terms related to metabolism, gut integrity, cellular development, and immunity (p ≤ 0.05). The KEGG analysis showed that differentially expressed genes (DEGs) in the LAPST group were primarily involved in pathways related to gut integrity, immunity, and metabolism, such as MAPK, PI3K-Akt, AMPK, the tryptophan metabolism, the glycine, serine, and threonine metabolism, ECM-receptor interaction, and others. Additionally, the fecal metabolic analysis identified 1215 upregulated and 305 downregulated metabolites in the LAPST vs. CPG group, implying their involvement in KEGG pathways including bile secretion, propanoate metabolism, arginine and proline metabolism, amino acid biosynthesis, and protein digestion and absorption, which are vital for maintaining barrier integrity, immunity, and metabolism. In conclusion, these findings suggest that the administration of a probiotic mixture improves immunity, maintains gut homeostasis and barrier integrity, and enhances metabolism in Salmonella infection.

Association between oral microbial dysbiosis and poor functional outcomes in stroke-associated pneumonia patients

BACKGROUND

Despite advances in our understanding of the critical role of the microbiota in stroke patients, the oral microbiome has rarely been reported to be associated with stroke-associated pneumonia (SAP). We sought to profile the oral microbial composition of SAP patients and to determine whether microbiome temporal instability and special taxa are associated with pneumonia progression and functional outcomes.

METHODS

This is a prospective, observational, single-center cohort study that examined patients with acute ischemic stroke (AIS) who were admitted within 24 h of experiencing a stroke event. The patients were divided into three groups based on the occurrence of pneumonia and the use of mechanical ventilation: nonpneumonia group, SAP group, and ventilator-associated pneumonia (VAP) group. We collected oral swabs at different time points post-admission and analyzed the microbiota using 16 S rRNA high-throughput sequencing. The microbiota was then compared among the three groups.

RESULTS

In total, 104 nonpneumonia, 50 SAP and 10 VAP patients were included in the analysis. We found that SAP and VAP patients exhibited significant dynamic differences in the diversity and composition of the oral microbiota and that the magnitude of this dysbiosis and instability increased during hospitalization. Then, by controlling the potential effect of all latent confounding variables, we assessed the changes associated with pneumonia after stroke and explored patients with a lower abundance of Streptococcus were more likely to suffer from SAP. The logistic regression analysis revealed that an increase in specific taxa in the phylum Actinobacteriota was linked to a higher risk of poor outcomes. A model for SAP patients based on oral microbiota could accurately predict 30-day clinical outcomes after stroke onset.

CONCLUSIONS

We concluded that specific oral microbiota signatures could be used to predict illness development and clinical outcomes in SAP patients. We proposed the potential of the oral microbiota as a non-invasive diagnostic biomarker in the clinical management of SAP patients.

CLINICAL TRIAL REGISTRATION

NCT04688138. Registered 29/12/2020, https://clinicaltrials.gov/ct2/show/NCT04688138 .

Quantitative oral health assessments in mechanically ventilated patients: A scoping review

BACKGROUND

Oral health is a key contributor to a person's overall health. Previous studies indicate that oral health deteriorates throughout ventilation and may contribute to the development of ventilator-associated pneumonia (VAP). Oral health at the time of initial ventilation may impact on this deterioration.

AIMS

To determine the quantitative clinical assessment methods used to measure oral health and what is currently known regarding the oral health of patients at the time of initial ventilation.

STUDY DESIGN

A systematic literature search using electronic bibliographic databases MEDLINE/PubMed, Embase, CINAHL, and the Cochrane Library was undertaken for this scoping review. Studies were included if patients were >18 years old and mechanically ventilated for <48 h at the time of the first oral assessment.

RESULTS

In total, 12 studies were included. The review demonstrates a limited understanding of clinical oral health at the time of initial ventilation. Significant variation in both assessment methods and reporting of oral health makes comparison of results difficult resulting in a poor overall understanding of oral health at the time of intubation.

CONCLUSION

Standardized assessment and reporting methods may improve clinical application of findings and help direct future research. We suggest developing a core outcome set to ensure consistent use of assessment tools as well as standardized reporting of results.

RELEVANCE TO CLINICAL PRACTICE

It is essential that a good understanding of oral health at the time of initial ventilation is gained so that patients receive more targeted oral hygiene intervention in ICU, potentially leading to improved patient outcomes.

Probiotics for Infection Prevention in Critically Ill and Trauma Patients: A Concise Review

BACKGROUND

Critically ill trauma patients are at an increased risk for infection, which can increase morbidity and mortality. The use of probiotic preparations for infection prevention is promising, yet the results of their effectiveness are mixed.

OBJECTIVES

To synthesize current research regarding the use of probiotics to prevent and possibly treat infection in the critically ill adult trauma population.

METHODS

RESULTS

CONCLUSION

Upon reviewing the current body of evidence, one cannot definitively conclude that probiotic supplementation in the critically-ill trauma population decreases health care-associated infection rates and improves outcomes, but most published evidence supports their use.

Effect of Oral Care with Povidone-Iodine in the Prevention of Ventilator-Associated Pneumonia; a Systematic Review and Meta-Analysis

Introduction

Ventilator-associated pneumonia (VAP) is one of the most common nosocomial infections affecting one-third of patients with mechanical ventilation. This study aimed to synthesize available evidence regarding the effect of treatment with povidone-iodine (PI) among adult patients admitted to intensive care units (ICUs) for the prevention of VAP.

Methods

An extensive search was conducted in online databases, including PubMed, Web of Science and Scopus, from the earliest records until January 1, 2023. STATA software v14 was used for statistical analysis. Publication bias was assessed via funnel plot, Begg's and Egger's tests. A P-value less than 0.1 was considered statistically significant for publication bias value.

Results

Four studies were included in the meta-analysis. Three studies showed rhat PI decreased VAP compared to the placebo group, but it was not statistically significant (RR: 0.61, 95%CI: 0.25 to 1.47, Z=1.10, P=0.27, I2:71.5%). One study compared the effect of PI with chlorhexidine on the rate of VAP, the difference between which was not statistically significant (RR: 1.50, 95%CI: 0.46 to 4.87, Z=0.67, P=0.50, I2:0). Two studies demonstrated that the use of PI intervention compared to placebo decreased the average length of stay in ICU; however, it was not statistically significant (WMD: -0.35, 95%CI:-3.90 to 3.20, Z=0.19, P=0.85, I2:0). Also, three studies showed that using PI had almost no effect on mortality rate compared to placebo (RR: 1.05, 95%CI: 0.66 to 1.53, Z=0.8, P=0.27, I2:29.0%).

Conclusion

More rigorously designed randomized clinical trials and further evidence are required to make a better decision/comparison about using PI as a suitable choice for preventing VAP among adult patients admitted to the ICU.

Integrative analysis of the metabolome and transcriptome reveals the influence of Lactobacillus plantarum CCFM8610 on germ-free mice

This study describes the influence of Lactobacillus plantarum CCFM8610 on the host by employing transcriptome and untargeted metabolomics. According to the enrichment analysis, three pathways, including the complement and coagulation cascade pathway, antigen processing and presentation pathways, and protein processing in the endoplasmic reticulum pathway, were affected by L. plantarum CCFM8610 colonization. According to partial least squares-discriminant analysis, five metabolites, L-methionine, D-tryptophan, indoleacrylic acid, DL-acetylcarnitine, and L-norleucine, were identified as key metabolites in the serum. Furthermore, integrative analysis of the metabolome and transcriptome revealed connections between enriched pathways and differential metabolites, and the regulation strategy of choline by affecting gene expression was proposed. Overall, the effects of L. plantarum CCFM8610 on host health were investigated after excluding the influence of gut microbes, which provides a valuable reference for studying the potential mechanisms of the effect of probiotics on host health.

Decreasing the Adverse Effects in Pelvic Radiation Therapy: A Randomized Controlled Trial Evaluating the Use of Probiotics

PURPOSE

The aim of this randomized controlled trial was to evaluate the potential benefit from 2 probiotic bacteria of the species Lactiplantibacillus plantarum against radiation therapy-induced comorbidities.

METHODS AND MATERIALS

Women (>18 years of age) scheduled for radiation therapy because of gynecologic cancer were randomly allocated to consume placebo or either low-dose probiotics (1 × 10¹⁰ colony-forming unit/capsule twice daily) or high-dose probiotics (5 × 10¹⁰ colony-forming unit/capsule twice daily). The intervention started approximately 1 week before the onset of radiation therapy and continued until 2 weeks after completion. During this period the participants were daily filling in a study diary documenting the incidence and severity of symptoms, intake of concomitant medication, and stool consistency. The primary endpoint was the probiotic effect on the mean number of loose stools during radiation therapy.

RESULTS

Of the 97 randomized women, 75 provided data for the analysis of the results. The mean number of loose stools (sum of Bristol stool type 6 and 7) was not significantly reduced in the probiotic groups, but there was a significant reduction in the mean number of days with >1 loose stool with 15.04 ± 8.92 days in the placebo and 8.65 ± 5.93 days in the high-dose probiotics group (P = .014). The benefit was even more pronounced in the 2 weeks following the end of radiation therapy (P = .005). Moreover, intake of the probiotics resulted in a reduced severity of the symptoms grinding abdominal pain (P = .041) and defecation urgency (P = .08) and a reduced percentage of days with these symptoms (P = .023 and P = .042, respectively), compared with placebo. There were no differences regarding reported adverse events.

CONCLUSIONS

Intake of the 2 probiotic bacteria was beneficial and reduced many measures or symptoms of the radiation-induced toxicity in women treated for gynecologic cancer.

The Impact of Improved Oral Care Methods on the Oral Health of Patients Undergoing Transoral Mechanical Ventilation

Objective

To explore the effects of improved oral care on the number of oropharyngeal bacteria and the incidence of ventilator-associated pneumonia in patients undergoing mechanical ventilation through oral endotracheal intubation by improving conventional oral care methods and operating procedures and to evaluate the quality of improved oral care and effect.

Methods

A total of 100 cases of mechanically ventilated patients with oral endotracheal intubation who met the inclusion criteria were randomly divided into the observation group and control group with 50 cases each. The control group took routine oral care, that is, scrubbing 3 times per day, and the oral care solution was selected as physiological brine. The observation group improved the conventional oral care method, namely, oral scrubbing before intubation, brushing and washing after intubation, 3 times per day, and 0.1% povidone-iodine in oral care solution. Analysis and comparison of the oral bacterial flora, oral cleanliness, and incidence of ventilator-associated pneumonia, mechanical ventilation time, ICU hospitalization time, and mortality rate of the two groups of patients were analyzed and compared. The relevant data were collected and processed for statistical processing.

Results

The oral bacterial flora of the two groups of patients before oral care after mechanical ventilation after oral tracheal intubation was compared, and there was no significant statistical difference (P > 0.05). After nursing, the oral bacterial flora of the observation group at 8 h, 16 h, and 24 h after intubation was significantly lower than that of the control group. Statistics showed that the difference was statistically significant (P < 0.05). After nursing, the number of patients with oral cleanliness in the observation group was significantly higher than that of the control group, while the incidence of ventilator-associated pneumonia in the observation group was 8% significantly lower than that of the control group 14%. Statistics show that this difference is statistically significant (P < 0.05). After nursing, the observation group's oral cleanliness score, mechanical ventilation time, ICU hospitalization time, and GCS score were better than those of the control group. Statistics showed that the difference was statistically significant (P < 0.05). The mortality of the observation group was significantly lower than that of the control group, which was not statistically significant (P > 0.05).

Conclusion

Oral care can effectively reduce the number of oropharyngeal bacteria in patients who are mechanically ventilated through orotracheal intubation and significantly reduce the incidence of ventilator-associated pneumonia.

Probiotic in the prevention of ventilator-associated pneumonia in critically ill patients: evidence from meta-analysis and trial sequential analysis of randomized clinical trials

BACKGROUND

Probiotic might have a role in the prevention of ventilator-associated pneumonia (VAP) among mechanically ventilated patients, but the efficacy and safety remained inconsistent. The aim of this systematic review and meta-analysis was to evaluate the efficacy and safety of probiotic (prebiotic, synbiotic) versus placebo in preventing VAP in critically ill patients undergoing mechanical ventilation.

METHODS

PubMed, Embase and the Cochrane library databases were searched to 10 October 2021 without language restriction for randomized or semi-randomized controlled trials evaluating probiotic (prebiotic, synbiotic) vs. placebo in prevention of VAP in critically ill mechanically ventilated patients. The pooled relative risk (RR) along with 95% confidence intervals (CI) were combined using a random-effects model. Furthermore, the trial sequential analysis (TSA) and subgroup analyses were performed. Statistical significance was regarded as P < 0.05.

RESULTS

Twenty-three trials involving 5543 patients were eligible for this meta-analysis. The combined RR of decreasing the risk of VAP by probiotic was 0.67 (0.56, 0.81) for all eligible studies, 0.69 (n = 5136; 95% CI = 0.57 to 0.84; P < 0.01) for adults studies and 0.55 (n = 407; 95%CI = 0.31 to 0.99; P = 0.046) for neonates/children studies. Additionally, the above-mentioned positive finding in 20 adults studies was verified by the results of TSA, subgroup analyses and cumulative meta-analysis. Ample evidences demonstrated a 31% decrease in RR of incidence of VAP was noted when prophylactic probiotic therapy was administrated among adult patients. Finally, there were no effects on the ICU/hospital/28-/90-day mortality, bacteremia, CRBSI, diarrhea, ICU-acquired infections, infectious complications, pneumonia, UTI and wound infection between two groups (P > 0.05 for all).

CONCLUSIONS

Based on the results of our study, the current evidences suggested that prophylactic administration of probiotic might be utilized as a preventive method for VAP in neonates/children and adults patients who required mechanical ventilation. However, further large, high-quality RCTs are warranted to assess the efficacy and safety of probiotic treatment in critically ill patients, especially for the neonates/children studies and the long-term consequences of this therapy.

Exploring the Nursing Factors Related to Ventilator-Associated Pneumonia in the Intensive Care Unit

Objective

The purpose of this study was to investigate the key nursing factors associated with ventilator-associated pneumonia (VAP) in critical care patients.

Methods

Through the quality control platform of Hebei Province, questionnaires were sent to intensive care nurses in 32 tertiary hospitals in Hebei Province, China to collect data concerning the incidence of VAP and the status of the nursing staff. All the data were analyzed using an independent t-test and a one-way analysis of variance (ANOVA). The Pearson correlation coefficient was used to analyse the correlation between the nursing factors and the incidence of VAP. Multivariate logistic regression analysis was used to determine the risk factors affecting VAP.

Results

In terms of nursing, the incidence of VAP was affected by the differential nursing strategies. Multivariate logistic regression analysis showed that the incidence of VAP was significantly associated with the following six variables: the ratio of nurses to beds (p = 0.000), the ratio of nurses with a bachelor's degree or higher (p = 0.000), the ratio of specialist nurses (p = 0.000), the proportion of nurses with work experience of 5–10 years (p = 0.04), the number of patients nurses were responsible for at night (p = 0.01) and the frequency of oral care (p = 0.000).

Conclusion

The incidence of VAP is closely related to nursing factors. In terms of nursing human resources, even junior nurses (less experienced nurses) can play an essential role in reducing VAP. In addition, to reduce VAP, the number of patients that nurses are responsible for at night should be reduced as much as possible, and improving nursing qualifications.

Is Chlorhexidine in Dentistry an Ally or a Foe? A Narrative Review

Chlorhexidine has been one of the most effective and popular antiseptic substances used in medicine for decades. In dentistry, it has been used in endodontics, periodontology, surgery, and general dentistry. It is also widely used daily by patients in mouth rinses, gels, or toothpastes. Because of its multiple uses, we should follow all types of research reporting its potential adverse effects. This article aims to review the most up-to-date studies regarding chlorhexidine and its possible side effects, in the period of the SARS-CoV-2 pandemic, as the use of different antiseptic substances has rapidly increased.

Probiotics for the Prevention of Ventilator-Associated Pneumonia: An Updated Systematic Review and Meta-Analysis of Randomised Controlled Trials

BACKGROUND

Presently, there is conflicting evidence regarding the efficacy of probiotics in the prevention of ventilator-associated pneumonia (VAP). This meta-analysis was conducted to update current clinical evidence and evaluate the efficacy and safety of probiotics for the prevention of VAP.

METHODS

We searched three databases and two trial registers to retrieve randomised controlled trials (RCTs) comparing probiotics or synbiotics with placebo or standard treatment for the prevention of VAP in adult patients receiving mechanical ventilation in the intensive care unit (ICU).

RESULTS

Our meta-analysis included 18 RCTs involving 4893 patients. Our results showed that probiotics may reduce the incidence of VAP (RR 0.68, 95% CI: 0.55-0.84; low certainty). However, in our subgroup and sensitivity analyses, the effect was not significant in double-blind studies, and in studies with a low risk of bias in the randomisation process. Probiotics reduced the length of ICU stay (MD -2.22 days, 95% CI: -4.17 to -0.28; moderate certainty) and the duration of antibiotic use (MD -1.25 days, 95% CI -1.86 to -0.64; moderate certainty).

CONCLUSIONS

Probiotics may reduce the incidence of VAP but due to the low quality of pooled evidence, the use of probiotics warrants caution. Further, large-scale, high-quality RCTs need to be conducted to provide conclusive evidence.

New Insights in the Pathophysiology of Hospital- and Ventilator-Acquired Pneumonia: A Complex Interplay between Dysbiosis and Critical-Illness-Related Immunosuppression

Both hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP) have long been considered as diseases resulting from the invasion by pathogens of a previously sterile lung environment. Based on this historical understanding of their pathophysiology, our approaches for the prevention and treatment have significantly improved the outcomes of patients, but treatment failures remain frequent. Recent studies have suggested that the all-antimicrobial therapy-based treatment of pneumonia has reached a glass ceiling. The demonstration that the constant interactions between the respiratory microbiome and mucosal immunity are required to tune homeostasis in a state of symbiosis has changed our comprehension of pneumonia. We proposed that HAP and VAP should be considered as a state of dysbiosis, defined as the emergence of a dominant pathogen thriving at the same time from the catastrophic collapse of the fragile ecosystem of the lower respiratory tract and from the development of critical-illness-related immunosuppression. This multidimensional approach to the pathophysiology of HAP and VAP holds the potential to achieve future successes in research and critical care. Microbiome and mucosal immunity can indeed be manipulated and used as adjunctive therapies or targets to prevent or treat pneumonia.

Clinical Benefits From Administering Probiotics to Mechanical Ventilated Patients in Intensive Care Unit: A PRISMA-Guided Meta-Analysis

Background

The use of probiotics has been considered as a new intervention for ventilator-associated pneumonia (VAP) prevention in the intensive care unit (ICU). The aim of this meta-analysis was to evaluate the effect of probiotics on mechanical-ventilated patients in ICU.

Methods

PubMed, Embase, Scopus, and the Cochrane Library were searched for relevant randomized controlled trials (RCTs) from their respective inception through October 10, 2021. All studies meeting the inclusion criteria were selected to evaluate the effect of probiotics on patients receiving mechanical ventilation in ICU.

Results

A total of 15 studies involving 4,693 participants met our inclusion criterion and were included in this meta-analysis. The incidence of VAP in the probiotic group was significantly lower (odds ratio [OR] 0.58, 95% CI 0.41 to 0.81; p = 0.002; I² = 71%). However, a publication bias may be present as the test of asymmetry was significant (p = 0.007). The probiotic administration was associated with a significant reduction in the duration of mechanical ventilation (mean difference [MD] −1.57, 95% CI −3.12 to −0.03; p = 0.05; inconsistency [I]² = 80%), length of ICU stay (MD −1.87, 95% CI −3.45 to −0.28; p = 0.02; I² = 76%), and incidence of bacterial colonization (OR 0.59, 95% CI 0.45 to 0.78; p = 0.0001; I² = 34%). Moreover, no statistically significant differences were observed regarding the incidence of diarrhea (OR 0.90, 95% CI 0.65 to 1.25; p = 0.54; I² = 12%) and mortality (OR 0.91, 95% CI 0.80 to 1.05; p = 0.19; I² = 0%) between probiotics group and control group.

Conclusion

Our meta-analysis shows that probiotics are associated with a reduction in VAP, as well as the duration of mechanical ventilation, ICU length of stay, and bacterial colonization, but no significant effects on ICU mortality and occurrence of diarrhea. However, in consideration of the significant heterogeneity and publication bias, our findings need to be further validated.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/, identifier: CRD42020150770.

Human Microbiome and Its Medical Applications

The commensal microbiome is essential for human health and is involved in many processes in the human body, such as the metabolism process and immune system activation. Emerging evidence implies that specific changes in the microbiome participate in the development of various diseases, including diabetes, liver diseases, tumors, and pathogen infections. Thus, intervention on the microbiome is becoming a novel and effective method to treat such diseases. Synthetic biology empowers researchers to create strains with unique and complex functions, making the use of engineered microbes for clinical applications attainable. The aim of this review is to summarize recent advances about the roles of the microbiome in certain diseases and the underlying mechanisms, as well as the use of engineered microbes in the prevention, detection, and treatment of various diseases.

Gut-lung cross talk in COVID-19 pathology and fatality rate

Coronavirus disease 2019 (COVID-19) is the leading pandemic facing the world in 2019/2020; it is caused by a novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, which necessitates clear understanding of the infectious agent. The virus manifests aggressive behavior with severe clinical presentation and high mortality rate, especially among the elderly and patients living with chronic diseases. In the recent years, the role of gut microbiota, in health and disease, has been progressively studied and highlighted. It is through gut microbiota-organ bidirectional pathways, such as gut-brain axis, gut-liver axis, and gut-lung axis, that the role of gut microbiota in prompting lung disease, among other diseases, has been proposed and accepted. It is also known that respiratory viral infections, such as COVID-19, induce alterations in the gut microbiota, which can influence immunity. Based on the fact that gut microbiota diversity is decreased in old age and in patients with certain chronic diseases, which constitute two of the primary fatality groups in COVID-19 infections, it can be assumed that the gut microbiota may play a role in COVID-19 pathology and fatality rate. Improving gut microbiota diversity through personalized nutrition and supplementation with prebiotics/probiotics will mend the immunity of the body and hence could be one of the prophylactic strategies by which the impact of COVID-19 can be minimized in the elderly and immunocompromised patients. In this chapter, the role of dysbiosis in COVID-19 will be clarified and the possibility of using co-supplementation of personalized prebiotics/probiotics with current therapies will be discussed.

The effect of different concentrations of chlorhexidine on microbial colonization: A double-blinded randomized controlled study

AIM

Study aims were to determine the most effective chlorhexidine concentration to be used in reducing microbial colonization in patients under mechanical ventilation and to examine the effect of oral care using different concentrations on the integrity of the oral mucous membranes.

DESIGN

This research was a randomized controlled double-blinded experimental study.

METHOD

The sample of study consisted of the 116 adult patients who remained intubated. Oral care was given to patients 4 times/day as per nurse protocol. Every morning during for 4 days, the intraoral mucosa of all groups of patients was assessed. Microbial colonization samples from oral mucosa were taken in the morning before oral care. A determination of the species of microorganisms in these samples was made.

RESULTS

A statistically significant difference was found with regard to the reproduction of microorganisms between the oral mucosa samples taken from patients using 2% and 1% chlorhexidine solutions (P < 0.001). In the cultures taken from patients on the first and fourth days of intubation, a total of 36 different microorganisms were seen to be reproducing.

CONCLUSION

It was concluded that the most effective oral solution for the prevention of microbial colonization in patients under mechanical ventilation was chlorhexidine 1%.

Effects of Probiotics in Conditions or Infections Similar to COVID-19 on Health Outcomes: An Evidence Analysis Center Scoping Review

Probiotics have been suggested as a potential intervention for improving outcomes, particularly ventilatory-associated pneumonia, in patients infected with coronavirus disease 2019 (COVID-19). However, with the rapid development of the COVID-19 pandemic, there is little direct evidence available in infected patients. The objective of this scoping review is to examine the availability and nature of literature describing the effect of probiotics in adults with conditions or infections similar to COVID-19 infection on related health outcomes. MEDLINE, Cumulative Index to Nursing & Allied Health Literature, and Cochrane Databases were searched for studies published from 1999 to May 1, 2020, examining the effect of probiotics in conditions applicable to individuals infected with COVID-19, including, but not limited to, other forms of coronavirus, critical illness, and mechanical ventilation. The databases search identified 1925 unique articles, 77 full-text articles were reviewed, and 48 studies were included in this scoping review, including 31 primary studies and 17 systematic reviews. Primary studies examined a range of interventions that varied by probiotic diversity and types, including 8 studies that focused on synbiotics, which include both pre- and probiotics. Several systematic reviews examined the effect of probiotics on ventilator-associated pneumonia and other infections. Although most systematic reviews concluded probiotics may improve these outcomes, most systematic review authors concluded that the evidence was low in quality and high in heterogeneity. In the absence of direct evidence with patients infected with COVID-19, studies in comparable populations are currently the best resource to guide probiotics interventions in conjunction with clinical expertise and multidisciplinary health care planning.

Do probiotics help prevent ventilator-associated pneumonia in critically ill patients? A systematic review with meta-analysis

BACKGROUND

Probiotic treatments might contribute to the prevention of ventilator-associated pneumonia (VAP). Due to its unclear clinical effects, here we intend to assess the preventive effect and safety of probiotics on intensive care unit (ICU) patients.

METHODS

Eligible randomised controlled trials were selected in databases until 30 September 2019. The characteristics of the studies were extracted, including study design, definition of VAP, probiotics intervention, category of included patients, incidence of VAP, mortality, duration of mechanical ventilation (MV) and ICU stay. Heterogeneity was evaluated by Chi-squared and I2 tests.

RESULTS

15 studies involving 2039 patients were identified for analysis. The pooled analysis suggests significant reduction on VAP (risk ratio, 0.68; 95% Cl, 0.60 to 0.77; p<0.00001) in a fixed-effects model. Subgroup analyses performed on the category of clinical and microbiological criteria both support the above conclusion; however, there were no significant differences in duration of MV or length of ICU stay in a random-effects model. Also, no significant differences in total mortality, overall mortality, 28-day mortality or 90-day mortality were found in the fixed-effects model.

CONCLUSIONS

The probiotics helped to prevent VAP without impacting the duration of MV, length of ICU stay or mortality.

Efficacy of Lactiplantibacillus plantarum 299 and 299v against nosocomial oropharyngeal pathogens in vitro and as an oral prophylactic treatment in a randomized, controlled clinical trial

Background

Disturbance in the oropharyngeal microbiota is common in hospitalized patients and contributes to the development of nosocomial pneumonia. Lactiplantibacillus plantarum 299 and 299v (Lp299 and Lp299v) are probiotic bacteria with beneficial effects on the human microbiome.

Aim

To investigate how Lp299 and Lp299v affect the growth of nosocomial oropharyngeal pathogens in vitro and to evaluate the efficacy in vivo when these probiotics are administered prophylactically in hospitalized patients.

Methods

The in vitro effect of Lp299 and Lp299v on nosocomial respiratory tract pathogens was evaluated using two methods, the co‐culture and agar overlay. In the clinical study, patients were randomized to orally receive either probiotics or placebo twice daily during their hospital stay. Oropharyngeal swabs were analyzed at inclusion and every fourth day throughout hospitalization.

Findings

All tested pathogens were completely inhibited by both Lp299 and Lp299v using the agar‐overlay method. In the co‐culture experiment, Lp299 and Lp299v significantly (p < 0.05) reduced the growth of all pathogens except for Enterococcus faecalis co‐incubated with Lp299. In the clinical study, daily oral treatment with Lp299 and Lp299v did not influence the development of disturbed oropharyngeal microbiota or nosocomial infection. Proton pump inhibitors, antibiotics, and steroid treatment were identified as risk factors for developing disturbed oropharyngeal microbiota.

Conclusions

Lp299 and Lp299v inhibited pathogen growth in vitro but did not affect the oropharyngeal microbiota in vivo. The ClinicalTrials.gov Identifier for this study is NCT02303301.

Preventive Effect of Probiotics on Ventilator-Associated Pneumonia: A Meta-analysis of 2428 Patients

BACKGROUND

Researchers had contradictory conclusions about the role of probiotics in preventing ventilator-associated pneumonia (VAP), which has led to the controversial use of probiotics in mechanically ventilated patients.

OBJECTIVE

To explore the efficacy and safety of probiotics in preventing VAP.

METHODS

A literature search was conducted in 7 medical databases. Two investigators assessed literature quality independently and collected data. The primary outcome was the incidence of VAP. Secondary outcomes included 16 measures. Sensitivity analysis and subgroup and meta-regression analyses were performed to analyze the source of heterogeneity. P values <0.05 were considered statistically significant, and CIs were set at 95%. A random-effects model was set when I² <50%, otherwise a fixed-effects model was used.

RESULTS

A total of 20 randomized controlled studies with a total of 2428 patients were analyzed. Pooled results showed positive effects of probiotics on the reduction of VAP incidence (risk ratio [RR] = 0.672; P < 0.001; I² = 11.3%), length of ICU stay (WMD = -1.417; P = 0.012; I² = 90.7%), oropharyngeal (RR = 0.866; P = 0.031; I² = 12.4%) and gastric (RR = 0.645; P < 0.001; I² = 30.2%) colonization.

CONCLUSIONS AND RELEVANCE

Probiotics can reduce the incidence of VAP and reduce oropharyngeal and gastric bacterial colonization. The results also suggest that probiotics do not cause adverse effects.

Antiseptic mouthwash, the nitrate-nitrite-nitric oxide pathway, and hospital mortality: a hypothesis generating review

Meta-analyses and several large cohort studies have demonstrated that antiseptic mouthwashes are associated with mortality in hospitalized patients. A clear pathogenic mechanism is lacking, leading to controversy and a reluctance to abandon or limit the use of antiseptic mouthwashes. Here, we generate the hypothesis that a disturbance in nitric oxide homeostasis by antiseptic mouthwashes may be responsible for the observed increase in mortality risk. Nitric oxide is essential in multiple physiological processes, and a reduction in nitric oxide bioavailability is associated with the occurrence or worsening of pathologies, such as atherosclerosis, diabetes, and sepsis. Oral facultative anaerobic bacteria are essential for the enterosalivary nitrate–nitrite–nitric oxide pathway due to their capacity to reduce nitrate to nitrite. Nitrate originates from dietary sources or from the active uptake by salivary glands of circulating nitrate, which is then excreted in the saliva. Because antiseptic mouthwashes eradicate the oral bacterial flora, this nitric oxide-generating pathway is abolished, which may result in nitric oxide-deficient conditions potentially leading to life-threatening complications such as ischaemic heart events or sepsis.

Efficacy of probiotics in the prevention of VAP in critically ill ICU patients: an updated systematic review and meta-analysis of randomized control trials

Introduction

Ventilator-associated pneumonia (VAP) is reported as the second most common nosocomial infection among critically ill patients with the incidence ranging from 2 to 16 episodes per 1000 ventilator days. The use of probiotics has been shown to have a promising effect in many RCTs. Our systematic review and meta-analysis were thus planned to determine the effect of probiotic use in critically ill ventilated adult patients on the incidence of VAP, length of hospital stay, length of ICU stay, duration of mechanical ventilation, the incidence of diarrhea, and the incidence of oropharyngeal colonization and in-hospital mortality.

Methodology

Systematic search of various databases (such as Embase, Cochrane, and Pubmed), published journals, clinical trials, and abstracts of the various major conferences were made to obtain the RCTs which compare probiotics with placebo for VAP prevention. The results were expressed as risk ratios or mean differences. Data synthesis was done using statistical software - Review Manager (RevMan) Version 5.4 (The Cochrane Collaboration, 2020).

Results

Nine studies met our inclusion criterion and were included in the meta-analysis. The incidence of VAP (risk ratio: 0.70, CI 0.56, 0.88; P = 0.002; I² = 37%), duration of mechanical ventilation (mean difference −3.75, CI −6.93, −0.58; P 0.02; I² = 96%), length of ICU stay (mean difference −4.20, CI −6.73, −1.66; P = 0.001; I² = 84%) and in-hospital mortality (OR 0.73, CI 0.54, 0.98; P = 0.04; I² = 0%) in the probiotic group was significantly lower than that in the control group. Probiotic administration was not associated with a statistically significant reduction in length of hospital stay (MD −1.94, CI −7.17, 3.28; P = 0.47; I² = 88%), incidence of oro-pharyngeal colonization (OR 0.59, CI 0.33, 1.04; P = 0.07; I² = 69%), and incidence of diarrhea (OR 0.59, CI 0.34, 1.03; P = 0.06; I² = 38%).

Discussion

Our meta-analysis shows that probiotic administration has a promising role in lowering the incidence of VAP, the duration of mechanical ventilation, length of ICU stay, and in-hospital mortality.

Study protocol for the safety and efficacy of probiotic therapy on days alive and out of hospital in adult ICU patients: the multicentre, randomised, placebo-controlled Restoration Of gut microflora in Critical Illness Trial (ROCIT)

INTRODUCTION

The effect of early and sustained administration of daily probiotic therapy on patients admitted to the intensive care unit (ICU) remains uncertain.

METHODS AND ANALYSIS

The Restoration Of gut microflora in Critical Illness Trial (ROCIT) study is a multicentre, randomised, placebo-controlled, parallel-group, two-sided superiority trial that will enrol 220 patients in five ICUs. Adult patients who are within 48 hours of admission to an ICU and are expected to require intensive care beyond the next calendar day will be randomised in a 1:1 ratio to receive early and sustained Lactobacillus plantarum 299v probiotic therapy in addition to usual care or placebo in addition to usual care. The primary endpoint is days alive and out of hospital to day 60.

ETHICS AND DISSEMINATION

ROCIT has been approved by the South Metropolitan Health Service Human Research Ethics Committee (ref: RGS00000004) and the St John of God Health Care Human Research Ethics Committee (ref: 1183). The trial results will be submitted for publication in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

Australian and New Zealand Clinical Trials Registry (ANZCTR12617000783325); Pre-results.

Gut microbiota in surgical and critically ill patients

Microbiota-defined as a collection of microbial organisms colonising different parts of the human body-is now recognised as a pivotal element of human health, and explains a large part of the variance in the phenotypic expression of many diseases. A reduction in microbiota diversity, and replacement of normal microbes with non-commensal, pathogenic or more virulent microbes in the gastrointestinal tract-also known as gut dysbiosis-is now considered to play a causal role in the pathogenesis of many acute and chronic diseases. Results from animal and human studies suggest that dysbiosis is linked to cardiovascular and metabolic disease through changes to microbiota-derived metabolites, including trimethylamine-N-oxide and short-chain fatty acids. Dysbiosis can occur within hours of surgery or the onset of critical illness, even without the administration of antibiotics. These pathological changes in microbiota may contribute to important clinical outcomes, including surgical infection, bowel anastomotic leaks, acute kidney injury, respiratory failure and brain injury. As a strategy to reduce dysbiosis, the use of probiotics (live bacterial cultures that confer health benefits) or synbiotics (probiotic in combination with food that encourages the growth of gut commensal bacteria) in surgical and critically ill patients has been increasingly reported to confer important clinical benefits, including a reduction in ventilator-associated pneumonia, bacteraemia and length of hospital stay, in small randomised controlled trials. However, the best strategy to modulate dysbiosis or counteract its potential harms remains uncertain and requires investigation by a well-designed, adequately powered, randomised controlled trial.

Pathophysiological role of respiratory dysbiosis in hospital-acquired pneumonia

Hospital-acquired pneumonia is a major cause of morbidity and mortality. The incidence of hospital-acquired pneumonia remains high globally and treatment can often be ineffective. Here, we review the available data and unanswered questions surrounding hospital-acquired pneumonia, discuss alterations of the respiratory microbiome and of the mucosal immunity in patients admitted to hospital, and explore potential approaches to stratify patients for tailored treatments. The lungs have been considered a sterile organ for decades because microbiological culture techniques had shown negative results. Culture-independent techniques have shown that healthy lungs harbour a diverse and dynamic ecosystem of bacteria, changing our comprehension of respiratory physiopathology. Understanding dysbiosis of the respiratory microbiome and altered mucosal immunity in patients with critical illness holds great promise to develop targeted host-directed immunotherapy to reduce ineffective treatment, to improve patient outcomes, and to tackle the global threat of resistant bacteria that cause these infections.