Impact of the administration of probiotics on the incidence of ventilator-associated pneumonia: a meta-analysis of randomized controlled trials

Effect of Probiotics on the Incidence of Healthcare-Associated Infections in Mechanically Ventilated Neurocritical Care Patients

BACKGROUND

Healthcare-associated infections (HAIs) are seen in 17% of critically ill patients. Probiotics, live nonpathogenic microorganisms, may aid in reducing the incidence of infection in critically ill patients. We hypothesized that administration of probiotics would be safe and reduce the incidence of HAIs among mechanically ventilated neurocritical care patients.

METHODS

We assembled 2 retrospective cohorts of mechanically ventilated neurocritical care patients. In the preintervention cohort from July 1, 2011, to December 31, 2011, probiotics were not used. In the postintervention group from July 1, 2012, to December 31, 2012, 1 g of a combination of Lactobacillus acidophilus and Lactobacillus helveticus was administered twice daily to all patients who were mechanically ventilated for more than 24 hours.

RESULTS

There were a total of 167 patients included, 80 patients in the preintervention group and 87 patients in the postintervention group. No patients in the preintervention group received probiotics. Eighty-five (98%) patients in the postintervention group received probiotics for a median of 10 days (interquartile range, 4-20 days). There were 14 (18%) HAIs in the preintervention group and 8 (9%) HAIs in the postintervention group (P = .17). Ventilator days, lengths of stay, in-hospital mortality, and discharge disposition were similar between the pre- and postintervention groups. There were no cases of Lactobacillus bacteremia or other adverse events associated with probiotics use.

CONCLUSION

Probiotics are safe to administer in neurocritical care patients; however, this study failed to demonstrate a significant decrease in HAIs or secondary outcomes associated with probiotics.

Hepatitis C status and infectious complications in the surgical intensive care unit: a retrospective analysis of 1,941 consecutive patients

BACKGROUND

Hepatitis C virus (HCV) infection is thought to be associated with immune dysfunction. We hypothesized that HCV status would be associated with increased infectious complications in the surgical intensive care unit (SICU).

METHODS

All patients admitted to our SICU between 2008 and 2012 were included. We evaluated 90-day mortality and infectious complications in the SICU. Multivariate logistic regression was performed to identify predictors of infectious complications and 90-day mortality.

RESULTS

A total of 1,941 patients were included. The HCV-positive group had a higher overall incidence of infectious complications (25% vs 18%), particularly ventilator-associated pneumonia (VAP) and bacteremia. The increased incidences of VAP and bacteremia persisted when cirrhotic patients were excluded. Prolonged intubation (Odds Ratio [OR] = 2.1), abdominal surgery (OR = 1.6), and model for end-stage liver disease ≥ 15 (OR = 1.4) were independent predictors of SICU infectious complications.

CONCLUSIONS

The HCV-positive group had an increased incidence of infectious complications in the SICU, particularly VAP and bacteremia. This effect persisted when cirrhotic patients were excluded.

Gut Microbiome: What We Do and Don't Know

Within the last decade, research regarding the human gut microbiome has exploded. While the gastrointestinal tract was once regarded simply as a digestive organ, new technologies have led the science world to wonder about the impact that the gut microbiota may have on human health and disease. The gut microbiome is now becoming known for its role in metabolism, immune defense, and behavior. From in utero variations to those that rapidly occur post partum, our gut microbiome changes with age, environment, stress, diet, and health status as well as medication exposure. This article reviews what is currently known regarding various influences on the gut microbiome and is meant to encourage the reader to further explore the unknown.

Use of probiotics to prevent ventilator-associated pneumonia: A survey of pharmacists' attitudes

PURPOSE

The primary objective of this survey was to describe pharmacists' attitudes regarding probiotic use in the intensive care unit (ICU); secondary objectives were to evaluate pharmacists' knowledge and use of probiotics for critically ill patients.

METHODS

The survey instrument was rigorously designed and pretested, then distributed in both English and French to Canadian ICU pharmacists. The online survey was open for 5 weeks, and 3 follow-up emails were sent to maximize response rates.

RESULTS

Of 303 eligible surveys, 191 were returned (63.0%). Probiotics were available in the hospitals of 69.8% (113/162) of respondents, and 62.0% (101/163) indicated that they had used probiotics for at least 1 ICU patient in the previous year. Most pharmacists (137/171, 80.1%) said that they would "never" consider recommending probiotics for prevention of ventilator-associated pneumonia in ICU patients, and this response was more common (P = .0074) among pharmacists who were "unsure" about the safety of probiotics in this population when compared to those who felt that they knew how safe probiotics are.

CONCLUSIONS

Most Canadian ICU pharmacists have used probiotics at least once in the ICU in the last year. However, based on uncertain efficacy and safety, most ICU pharmacists would not currently recommend probiotics for the prevention of ventilator-associated pneumonia.

Probiotics: Prevention of Severe Pneumonia and Endotracheal Colonization Trial-PROSPECT: protocol for a feasibility randomized pilot trial

BACKGROUND

Probiotics are defined as live microorganisms that may confer health benefits when ingested. Meta-analysis of probiotic trials suggests a 25 % lower ventilator-associated pneumonia (VAP) and 18 % lower infection rates overall when administered to patients in the intensive care unit (ICU). However, prior trials are small, largely single center, and at high risk of bias. Before a large rigorous trial is launched, testing whether probiotics confer benefit, harm, or have no impact, a pilot trial is needed. The aim of the PROSPECT Pilot Trial is to determine the feasibility of performing a larger trial in mechanically ventilated critically ill patients investigating Lactobacillus rhamnosus GG. A priori, we determined that the feasibility of the larger trial would be based on timely recruitment, high protocol adherence, minimal contamination, and an acceptable VAP rate.

METHODS/DESIGN

Patients ≥18 years old in the ICU who are anticipated to receive mechanical ventilation for ≥72 hours will be included. Patients are excluded if they are at increased risk of probiotic-associated infection, have strict enteral medication contraindications, are pregnant, previously enrolled in a related trial, or are receiving palliative care. Following informed consent, patients are randomized in variable unspecified block sizes in a fixed 1:1 ratio, stratified by ICU, and medical, surgical, or trauma admitting diagnosis. Patients receive 1 × 1010 colony forming units of L. rhamnosus GG (Culturelle, Locin Industries Ltd) or an identical placebo suspended in tap water administered twice daily via nasogastric tube in the ICU. Clinical and research staff, patients, and families are blinded.

DISCUSSION

The primary outcomes for this pilot trial are the following: (1) recruitment success, (2) ≥90 % protocol adherence, (3) ≤5 % contamination, and (4) ~10 % VAP rate. Additional clinical outcomes are VAP, other infections, diarrhea (total, antibiotic associated, and Clostridium difficile), ICU and hospital length of stay, and mortality. The morbidity, mortality, and cost of VAP underscore the need for cost-effective prophylactic interventions. The PROSPECT Pilot Trial is the initial step toward rigorously evaluating whether probiotics decrease nosocomial infections, have no effect, or actually cause infections in critically ill patients.

TRIAL REGISTRATION

ClinicalTrials.gov. NCT01782755.

Probiotic prophylaxis to prevent ventilator associated pneumonia (VAP) in children on mechanical ventilation: an open-label randomized controlled trial

PURPOSE

Ventilator associated pneumonia (VAP) is one of the most common nosocomial infections in the pediatric intensive care unit (PICU). It is associated with increased mortality and prolonged hospital stay. Several preventive strategies have been introduced to reduce VAP. One novel intervention is prophylactic administration of probiotics. Studies on the effect of probiotics on VAP in pediatric populations are lacking.

METHODS

This was an open-label randomized controlled trial. A total of 150 children no older than 12 years admitted to the PICU were recruited from November 2011 to July 2013. Children who were likely to require ventilation for more than 48 h were eligible for inclusion in the study. Patients were randomized into two groups after stratification based on age groups. Children in the intervention group received probiotic preparation twice a day beginning from the day of ICU admission till 7 days or discharge from ICU, whichever was earlier. The control group did not receive any placebo. Children were examined daily for evidence of VAP and were followed up till discharge from hospital. Incidence of VAP, duration of hospital stay, and mortality were compared.

RESULTS

Children who received prophylactic probiotics had a lower incidence of VAP compared to the control group (17.1 % in the probiotics group vs 48.6 % in the control group, p < 0.001; 22 per 1,000 ventilated days vs 39 per 1,000 ventilated days, p = 0.02). On multiple logistic regression analysis, use of prophylactic probiotics decreased the incidence of VAP by 77 % and reduced the duration of ICU and hospital stays by an average of 2.1 and 3.3 days, respectively, after adjusting for the other confounders. No complications due to administration of probiotics were observed in the study.

CONCLUSION

Prophylactic probiotics administration resulted in reduction of the incidence of VAP in critically ill children in a setting where baseline VAP rates are high. The intervention was found to be safe.

Strategies to prevent ventilator-associated pneumonia in acute care hospitals: 2014 update

Previously published guidelines are available that provide comprehensive recommendations for detecting and preventing healthcare-associated infections (HAIs). The intent of this document is to highlight practical recommendations in a concise format to assist acute care hospitals in implementing and prioritizing strategies to prevent ventilator-associated pneumonia (VAP) and other ventilator-associated events (VAEs) and to improve outcomes for mechanically ventilated adults, children, and neonates. This document updates “Strategies to Prevent Ventilator-Associated Pneumonia in Acute Care Hospitals,” published in 2008. This expert guidance document is sponsored by the Society for Healthcare Epidemiology of America (SHEA) and is the product of a collaborative effort led by SHEA, the Infectious Diseases Society of America (IDSA), the American Hospital Association (AHA), the Association for Professionals in Infection Control and Epidemiology (APIC), and The Joint Commission, with major contributions from representatives of a number of organizations and societies with content expertise. The list of endorsing and supporting organizations is presented in the introduction to the 2014 updates.

Patient-level interventions to prevent the acquisition of resistant gram-negative bacteria in critically ill patients: a systematic review

The rising incidence of multidrug-resistant Gram-negative bacterial (MDR-GNB) infections acquired in intensive care units has prompted a variety of patient-level infection control efforts. However, it is not known whether these measures are effective in reducing colonisation and infection. The purpose of this systematic review was to assess the efficacy of patient-level interventions for the prevention of colonisation with MDR-GNB and whether these interventions are associated with a reduction in the rate of infection due to MDR-GNB in the intensive care unit. Searches were conducted on PubMed, Cochrane, EMBASE and World of Science databases to identify comparative interventional studies on patient-level interventions implemented in the intensive care unit. Literature published in English, Spanish or French from January 1, 2000, until April 30, 2013, was searched. A total of 631 reports were found and we included and analysed 13 comparative studies that reported outcomes for an intervention compared with a control group. There were ten randomised and three observational interventional trials evaluating seven interventions. Overall, there was a reduction in colonisation (odds ratio [OR] 0.75; 95% confidence interval [CI] 0.66 to 0.85) and infection (OR 0.66; 95% CI 0.59 to 0.75) with MDR-GNB. This trend persisted after restricting pooled analysis to randomised controlled trials (pooled OR 0.66; 95% CI 0.57 to 0.76 and pooled OR 0.62; 95% CI 0.54 to 0.72, respectively). We identified a significant reduction in MDR-GNB colonisation and infection through the use of patient-level interventions. This effect was mostly accounted for by selective digestive decontamination. However, given the limitations of the analysed trials, adequately powered controlled studies are needed to further explore the effects of patient-level interventions on colonisation and infection with MDR-GNB.

Gut microbiome, gut function, and probiotics: Implications for health

New insights from a rapidly developing field of research have ushered in a new era of understanding of the complexity of host-microbe interactions within the human body. The paradigm shift from culturing to metagenomics has provided an insight into the complex diversity of the microbial species that we harbor, revealing the fact that we are in fact more microbes than human cells. The largest consortium of these microbes resides in the gut and is called the gut microbiota. This new science has expanded the ability to document shifts in microbial populations to an unparalleled degree. It is now understood that signals from the microbiota provide trophic, nutritional, metabolic, and protective effects for the development and maintenance of the host digestive, immune, and neuroendocrine system. Evidence linking changes in the gut microbiota to gastrointestinal and extraintestinal disorders like irritable bowel syndrome, inflammatory bowel disease, obesity, diabetes, and celiac disease have begun to emerge recently. Probiotics act through diverse mechanisms positively affecting the composition and/or function of the commensal microbiota and alter host immunological responses. Well-controlled intervention trials, systematic reviews, and meta-analysis provide convincing evidence for the benefit of probiotics in prevention and treatment of gastrointestinal as well as extraintestinal disorders.

Influence of a probiotic Lactobacillus casei strain on the colonisation with potential pathogenic streptococci and Staphylococcus aureus in the nasopharyngeal space of healthy men with a low baseline NK cell activity

The effect of a daily intake of the probiotic strain Lactobacillus casei Shirota (LcS) on the colonisation of pathogens, specifically streptococci and Staphylococcus aureus, in the nose and throat of healthy human volunteers with low natural killer cell activity, was investigated in a randomised and controlled intervention study. The study consisted of a 2-week run-in phase, followed by a 4-week intervention phase. The probiotic treatment group received a fermented milk drink with LcS, while the placebo group received an equally composed milk drink without the probiotic additive. To isolate potential pathogenic streptococci and Staph. aureus, samples from the pharynx, as well as of both middle nasal meati, were taken, once after the run-in phase and once at the end of the intervention phase. Isolated bacteria were identified as either Staph. aureus and α- or β-haemolytic streptococci in a polyphasic taxonomical approach based on phenotypic tests, amplified ribosomal DNA restriction analysis genotyping, and 16S rRNA gene sequencing of representative strains. Salivary secretory immunoglobulin A (SIgA) was used as marker of protective mucosal immunity to evaluate whether LcS treatment influenced SIgA production. No statistically significant effect could be determined for intervention with LcS on the incidence of Staph. aureus in the nasal space, Staph. aureus in the pharyngeal space or for β-haemolytic streptococci and Streptococcus pneumoniae in the pharyngeal space. Thus, the intervention did not influence the nasopharyngeal colonisation with Gram-positive potential pathogens. Production of salivary SIgA as a potential means of microbiota modulation was also not affected.

Probiotics for preventing ventilator-associated pneumonia

BACKGROUND

Ventilator-associated pneumonia (VAP) is common in intensive care units (ICUs). Some evidence indicates that probiotics may reduce the incidence of VAP. Several additional published studies have demonstrated that probiotics are safe and efficacious in preventing VAP in ICUs. We aimed to systematically summarise the results of all available data to generate the best evidence for the prevention of VAP.

OBJECTIVES

To evaluate the effectiveness and safety of probiotics for preventing VAP.

SEARCH METHODS

We searched CENTRAL (2014, Issue 8), MEDLINE (1948 to September week 1, 2014) and EMBASE (2010 to September 2014).

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing probiotics with placebo or another control (excluding RCTs that use probiotics in both study groups) to prevent VAP.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed eligibility and the quality of trials, and extracted data.

MAIN RESULTS

We included eight RCTs, with 1083 participants. All studies compared a form of probiotic (Lactobacillus casei rhamnosus; Lactobacillus plantarum; Synbiotic 2000FORTE; Ergyphilus; combination Bifidobacterium longum + Lactobacillus bulgaricus + Streptococcus thermophilus) versus a control group (placebo; glutamine; fermentable fibre; peptide; chlorhexidine). The analysis of all RCTs showed that the use of probiotics decreased the incidence of VAP (odds ratio (OR) 0.70, 95% confidence interval (CI) 0.52 to 0.95, low quality evidence). However, the aggregated results were uncertain for ICU mortality (OR 0.84, 95% CI 0.58 to 1.22 very low quality evidence), in-hospital mortality (OR 0.78, 95% CI 0.54 to 1.14, very low quality evidence), incidence of diarrhoea (OR 0.72, 95% CI 0.47 to 1.09, very low quality evidence), length of ICU stay (mean difference (MD) -1.60, 95% CI -6.53 to 3.33, very low quality evidence), duration of mechanical ventilation (MD -6.15, 95% CI -18.77 to 6.47, very low quality evidence) and antibiotic use (OR 1.23, 95% CI 0.51 to 2.96, low quality evidence). Antibiotics for VAP were used for a shorter duration (in days) when participants received probiotics in one small study (MD -3.00, 95% CI -6.04 to 0.04). However, the CI of the estimated effect was too wide to exclude no difference with probiotics. There were no reported events of nosocomial probiotic infections in any included study.The overall methodological quality of the included studies, based on our 'Risk of bias' assessments, was moderate with half of the included studies rated as a 'low' risk of bias; however, we rated four included studies as a 'high' risk of bias across one or more of the domains. The study limitations, differences in probiotics administered and participants, and small sample sizes across the included studies mean that the power to detect a trend of overall effect may be limited and chance findings cannot be excluded.To explore the influence of some potential confounding factors in the studies, we conducted an intention-to-treat (ITT) analysis, which did not change the inference of per-protocol analysis. However, our sensitivity analysis did not indicate a significant difference between groups for instances of VAP.

AUTHORS' CONCLUSIONS

Evidence suggests that use of probiotics is associated with a reduction in the incidence of VAP. However, the quality of the evidence is low and the exclusion of the one study that did not provide a robust definition of VAP increased the uncertainty in this finding. The available evidence is not clear regarding a decrease in ICU or hospital mortality with probiotic use. Three trials reported on the incidence of diarrhoea and the pooled results indicate no clear evidence of a difference. The results of this meta-analysis do not provide sufficient evidence to draw conclusions on the efficacy and safety of probiotics for the prevention of VAP in ICU patients.

Lactobacillus rhamnosus GG and Bifidobacterium longum attenuate lung injury and inflammatory response in experimental sepsis

Introduction

Probiotic use to prevent nosocomial gastrointestinal and potentially respiratory tract infections in critical care has shown great promise in recent clinical trials of adult and pediatric patients. Despite well-documented benefits of probiotic use in intestinal disorders, the potential for probiotic treatment to reduce lung injury following infection and shock has not been well explored.

Objective

Evaluate if Lactobacillus rhamnosus GG (LGG) or Bifidobacterium longum (BL) treatment in a weanling mouse model of cecal ligation and puncture (CLP) peritonitis will protect against lung injury.

Methods

3 week-old FVB/N mice were orally gavaged with 200 µl of either LGG, BL or sterile water (vehicle) immediately prior to CLP. Mice were euthanized at 24 h. Lung injury was evaluated via histology and lung neutrophil infiltration was evaluated by myeloperoxidase (MPO) staining. mRNA levels of IL-6, TNF-α, MyD88, TLR-4, TLR-2, NFΚB (p50/p105) and Cox-2 in the lung analyzed via real-time PCR. TNF-α and IL-6 in lung was analyzed via ELISA.

Results

LGG and BL treatment significantly improved lung injury following experimental infection and sepsis and lung neutrophil infiltration was significantly lower than in untreated septic mice. Lung mRNA and protein levels of IL-6 and TNF-α and gene expression of Cox-2 were also significantly reduced in mice receiving LGG or BL treatment. Gene expression of TLR-2, MyD88 and NFΚB (p50/p105) was significantly increased in septic mice compared to shams and decreased in the lung of mice receiving LGG or BL while TLR-4 levels remained unchanged.

Conclusions

Treatment with LGG and BL can reduce lung injury following experimental infection and sepsis and is associated with reduced lung inflammatory cell infiltrate and decreased markers of lung inflammatory response. Probiotic therapy may be a promising intervention to improve clinical lung injury following systemic infection and sepsis.

Tracheostomy after severe ischemic stroke: a population-based study

BACKGROUND

Stroke can result in varying degrees of respiratory failure. Some patients require tracheostomy in order to facilitate weaning from mechanical ventilation, long-term airway protection, or a combination of the two. Little is known about the rate and predictors of this outcome in patients with severe stroke. We aim to determine the rate of tracheostomy after severe ischemic stroke.

METHODS

Using the Nationwide Inpatient Sample database from 2007 to 2009, patients hospitalized with ischemic stroke were identified based on validated International Classification of Diseases, 9th revision, Clinical Modification codes. Next, patients with stroke were stratified based on whether they were treated with or without decompressive craniectomy, and the rate of tracheostomy for each group was determined. A logistic regression analysis was used to identify predictors of tracheostomy after decompressive craniectomy. Survey weights were used to obtain nationally representative estimates.

RESULTS

In 1,550,000 patients discharged with ischemic stroke nationwide, the rate of tracheostomy was 1.3% (95% confidence interval [CI], 1.2-1.4%), with a 1.3% (95% CI, 1.1-1.4%) rate in patients without decompressive craniectomy and a 33% (95% CI, 26-39%) rate in the surgical treatment group. Logistic regression analysis identified pneumonia as being significantly associated with tracheostomy after decompressive craniectomy (odds ratio, 3.95; 95% CI, 1.95-6.91).

CONCLUSIONS

Tracheostomy is common after decompressive craniectomy and is strongly associated with the development of pneumonia. Given its impact on patient function and potentially modifiable associated factors, tracheostomy may warrant further study as an important patient-centered outcome among patients with stroke.

Screening of Lactobacillus spp. for the prevention of Pseudomonas aeruginosa pulmonary infections

BACKGROUND

Pseudomonas aeruginosa is an opportunistic pathogen that significantly increases morbidity and mortality in nosocomial infections and cystic fibrosis patients. Its pathogenicity especially relies on the production of virulence factors or resistances to many antibiotics. Since multiplication of antibiotic resistance can lead to therapeutic impasses, it becomes necessary to develop new tools for fighting P. aeruginosa infections. The use of probiotics is one of the ways currently being explored. Probiotics are microorganisms that exert a positive effect on the host's health and some of them are known to possess antibacterial activities. Since most of their effects have been shown in the digestive tract, experimental data compatible with the respiratory environment are strongly needed. The main goal of this study was then to test the capacity of lactobacilli to inhibit major virulence factors (elastolytic activity and biofilm formation) associated with P. aeruginosa pathogenicity.

RESULTS

Sixty-seven lactobacilli were isolated from the oral cavities of healthy volunteers. These isolates together with 20 lactobacilli isolated from raw milks, were tested for their capacity to decrease biofilm formation and activity of the elastase produced by P. aeruginosa PAO1. Ten isolates, particularly efficient, were accurately identified using a polyphasic approach (API 50 CHL, mass-spectrometry and 16S/rpoA/pheS genes sequencing) and typed by pulsed-field gel electrophoresis (PFGE). The 8 remaining strains belonging to the L. fermentum (6), L. zeae (1) and L. paracasei (1) species were sensitive to all antibiotics tested with the exception of the intrinsic resistance to vancomycin. The strains were all able to grow in artificial saliva.

CONCLUSION

Eight strains belonging to L. fermentum, L. zeae and L. paracasei species harbouring anti-elastase and anti-biofilm properties are potential probiotics for fighting P. aeruginosa pulmonary infections. However, further studies are needed in order to test their innocuity and their capacity to behave such as an oropharyngeal barrier against Pseudomonas aeruginosa colonisation in vivo.

Prevention of ventilator-associated pneumonia

Invasive mechanical ventilation (IMV) represents a risk factor for the development of ventilator-associated pneumonia (VAP), which develops at least 48h after admission in patients ventilated through tracheostomy or endotracheal intubation. VAP is the most frequent intensive-care-unit (ICU)-acquired infection among patients receiving IMV. It contributes to an increase in hospital mortality, duration of MV and ICU and length of hospital stay. Therefore, it worsens the condition of the critical patient and increases the total cost of hospitalization. The introduction of preventive measures has become imperative, to ensure control and to reduce the incidence of VAP. Preventive measures focus on modifiable risk factors, mediated by non-pharmacological and pharmacological evidence based strategies recommended by guidelines. These measures are intended to reduce the risk associated with endotracheal intubation and to prevent microaspiration of pathogens to the lower airways.

[The influence of symbiotics in multi-organ failure: randomised trial]

BACKGROUND AND OBJECTIVE

To assess whether the administration of symbiotic preparations in patients with multi-organ failure (MOF) diminishes the evolution of the failure, the inflammatory response generated, the colonization pattern and the Intensive Care Unit (ICU) infectious illness.

PATIENTS AND METHOD

Randomized and controlled trial. All patients with MOF were included. Neutropenia and acute pancreatitis patients were excluded. A symbiotic (Simbiotic Drink) was administered via enteral feeding during the first 7 days. Variables of interest were: Sequential Organ Failure Assessment (SOFA) score evolution, systemic concentrations of lactate, fibrinogen and D-dimer; skin and mucosa colonization and infectious disease register.

RESULTS

Eighty-nine patients were included; 46 in the symbiotic group (SG) and 43 in the control group (CG). There were 68.5% males, with a median age of 69 years. There were no significant differences in the patients' fundamental characteristics (medical history, age, reason for admission, severity scores), nor in the length of ICU stay or in mortality. Comparing the SG with the CG, there were lower lactate levels on the second day, more fibrinogen levels on the days 5 and 7, and lower D-dimer levels on the day 7. Eight hundred and ninety-five cultures were performed for colonization assessment, with isolation of 528 microorganisms. No differences in microbiological resistance were found; there were more colonization in the SG by Candida in mucous membranes after the third day; this situation resolved after stopping symbiotic administration. Twenty-two patients suffered an infectious disease in ICU, 14 in SG (42.4%) and 19 in CG (57.6%). Although no differences were found in the microbiological pattern, there was a predominance of Candida spp. over other microorganisms (4 vs. 0 cases).

CONCLUSIONS

The symbiotic preparation Simbiotic Drink, administered in MOF, results in differences to improve the early lactate levels and late fibrinogen/D-dimer levels as well as mucosa colonization by Candida. There were no differences in the ICU evolution.

Bugs or drugs: are probiotics safe for use in the critically ill?

Probiotics are living microorganisms which have demonstrated many benefits in prevention, mitigation, and treatment of various disease states in critically ill populations. These diseases include antibiotic-associated diarrhea, Clostridium difficile diarrhea, ventilator-associated pneumonia, clearance of vancomycin-resistant enterococci from the GI tract, pancreatitis, liver transplant, major abdominal surgery, and trauma. However, their use has been severely limited due to a variety of factors including a general naïveté within the physician community, lack of regulation, and safety concerns. This article focuses on uses for probiotics in prevention and treatment, addresses current concerns regarding their use as well as proposing a protocol for safe use of probiotics in the critically ill patient.

Probiotics for preventing ventilator-associated pneumonia: a systematic review and meta-analysis of high-quality randomized controlled trials

Background

Ventilator-associated pneumonia (VAP) is considered to be a worldwide issue along with the development of supportive ventilation. The preventing strategy is of great importance for its poor prognostic and difficulties in treatment. Probiotics have been advocated as one of the possible preventive measures. We conducted a systematic review and meta-analysis to explore the potential benefits of probiotics.

Methods

The databases, Web of science, PubMed, Ovid and Cochrane lib were searched for randomized controlled trials (RCTs) publications that compared the effectiveness of probiotics with placebo in the prevention of VAP. The incidence of VAP was considered as the primary endpoint, mortality, length of stay in intensive care units (ICUs), etiology of the infections were considered as secondary endpoints.

Results

A total of 844 patients from 5 trials were subjected to meta-analysis. Probiotics did not significantly decrease the incidence of VAP (RR 0.94, 95%CI 0.85-1.04, p=0.22), however, the administration of probiotics reduced the risk of VAP caused by Pseudomonas aeruginosa (P. aeruginosa) (RR 0.30, 95%CI 0.11-0.91, P=0.03). It failed to affect any other endpoints.

Conclusion

Probiotic prophylaxis of ventilator-associated pneumonia remained inconclusive and it failed to improve the prognosis of general mechanically ventilated patients. It was noteworthy that infections caused by P. aeruginosa was reduced by administration of probiotics. In further, it is recommended that advanced studies should exploit transformation in pathogenic microorganisms owing to administration of probiotics as well as the specific population.

Probiotic administration reduces mortality and improves intestinal epithelial homeostasis in experimental sepsis

BACKGROUND

Recent clinical trials indicate that probiotic administration in critical illness has potential to reduce nosocomial infections and improve clinical outcome. However, the mechanism(s) of probiotic-mediated protection against infection and sepsis remain elusive. The authors evaluated the effects of Lactobacillus rhamnosus GG (LGG) and Bifidobacterium longum (BL) on mortality, bacterial translocation, intestinal epithelial homeostasis, and inflammatory response in experimental model of septic peritonitis.

METHODS

Cecal ligation and puncture (n=14 per group) or sham laparotomy (n=8 per group) were performed on 3-week-old FVB/N weanling mice treated concomitantly with LGG, BL, or vehicle (orally gavaged). At 24 h, blood and colonic tissue were collected. In survival studies, mice were given probiotics every 24 h for 7 days (LGG, n=14; BL, n=10; or vehicle, n=13; shams, n=3 per group).

RESULTS

Probiotics significantly improved mortality after sepsis (92 vs. 57% mortality for LGG and 92 vs. 50% mortality for BL; P=0.003). Bacteremia was markedly reduced in septic mice treated with either probiotic compared with vehicle treatment (4.39±0.56 vs. 1.07±1.54; P=0.0001 for LGG; vs. 2.70±1.89; P=0.016 for BL; data are expressed as mean±SD). Sepsis in untreated mice increased colonic apoptosis and reduced colonic proliferation. Probiotics significantly reduced markers of colonic apoptosis and returned colonic proliferation to sham levels. Probiotics led to significant reductions in systemic and colonic inflammatory cytokine expression versus septic animals. Our data suggest that involvement of the protein kinase B pathway (via AKT) and down-regulation of Toll-like receptor 2/Toll-like receptor 4 via MyD88 in the colon may play mechanistic roles in the observed probiotic benefits.

CONCLUSIONS

Our data demonstrate that probiotic administration at initiation of sepsis can improve survival in pediatric experimental sepsis. The mechanism of this protection involves prevention of systemic bacteremia, perhaps via improved intestinal epithelial homeostasis, and attenuation of the local and systemic inflammatory responses.

Immunomodulatory approaches for prevention and treatment of infectious diseases

With increasing pathogen resistance to antibiotics, population ageing, and threat of pandemics there is a strong interest in the development of new approaches for the treatment of infectious diseases. Immunomodulatory therapies are defined as interventions that target the host rather than the pathogen, modulating the immune response with the aim of disease prevention or treatment. Our growing understanding of the immune system continues to offer novel drug targets and approaches for immunomodulatory interventions. In this review we will cover prominent examples of immunomodulatory therapies already in clinical use, as well as the recent advances in the development of new immunomodulators in ongoing clinical trials.

Lack of efficacy of probiotics in preventing ventilator-associated pneumonia probiotics for ventilator-associated pneumonia: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Ventilator-associated pneumonia (VAP) remains a common hazardous complication in patients who are mechanically ventilated and is associated with increased morbidity and mortality.We undertook a systematic review and meta-analysis of randomized controlled trials to evaluate the efficacy and safety of probiotics for the prevention of VAP.

METHODS

The PubMed and EMBASE databases were searched to identify randomized controlled trials comparing probiotics with control for VAP in adult patients undergoing mechanical ventilation.The primary outcome was the incidence of VAP. Secondary outcomes included ICU mortality,hospital mortality, urinary tract infection, catheter-related bloodstream infection, diarrhea, length of ICU stay, length of hospital stay, and duration of mechanical ventilation.

RESULTS

A total of 1,142 patients from seven trials were subjected to meta-analysis. Probiotics did not significantly decrease the incidence of VAP (OR, 0.82; 95% CI, 0.55-1.24; P 5 .35), with low heterogeneity among the studies ( I 2 5 36.5%, P 5 .15). Probiotics also did not appear to significantly alter any of the other meta-analysis end points.

CONCLUSIONS

The limited evidence suggests that probiotics show no beneficial effect in patients who are mechanically ventilated; thus, probiotics should not be recommended for routine clinical application. However, the results of this meta-analysis should be interpreted with caution because of the heterogeneity among study designs. Future studies should focus on the safety of probiotics.

Impact of the administration of probiotics on mortality in critically ill adult patients: a meta-analysis of randomized controlled trials

BACKGROUND

The objective of this study was to systematically review and quantitatively synthesize all randomized controlled trials (RCTs) that have compared important outcomes in critically ill patients who received an administration of probiotics.

METHODS

A systematic literature search of PubMed, Scopus, and the Cochrane Central Register of Controlled Trials was conducted using specific search terms. Eligible studies were RCTs that compared the effect of prebiotics, probiotics, or synbiotics administration with control on ICU and hospital mortality rates in critically ill adult patients. Weighted mean differences (WMDs), pooled ORs, and 95% CIs were calculated using the Mantel-Haenszel fixed- and random-effects models.

RESULTS

Thirteen trials with 1,439 patients were analyzed. Probiotics did not significantly reduce ICU (OR, 0.85; 95% CI, 0.63-1.15) or hospital (OR, 0.90; 95% CI, 0.65-1.23) mortality. By contrast, probiotics administration reduced the incidence of ICU-acquired pneumonia (OR, 0.58; 95% CI, 0.42-0.79) and was associated with a shorter stay in the ICU (WMD, -1.49 days; 95% CI, -2.12 to -0.87 days). Finally, probiotics use was not associated with a shorter duration of mechanical ventilation (WMD, -0.18 days; 95% CI, -1.72-1.36 days) or a shorter hospital length of stay (WMD, -0.45 days; 95% CI, -1.41-0.52 days).

CONCLUSIONS

The present meta-analysis suggests that the administration of probiotics did not significantly reduce ICU or hospital mortality rates but did reduce the incidence of ICU-acquired pneumonia and ICU length of stay.

Probiotics: a new way to fight bacterial pulmonary infections?

Antibiotics, of which Fleming has identified the first representative, penicillin, in 1928, allowed dramatical improvement of the treatment of patients presenting with infectious diseases. However, once an antibiotic is used, resistance may develop more or less rapidly in some bacteria. It is thus necessary to develop therapeutic alternatives, such as the use of probiotics, defined by the World Health Organization (WHO) as "micro-organisms which, administered live and in adequate amounts, confer a benefit to the health of the host". The scope of these micro-organisms is broad, concerning many areas including that of infectious diseases, especially respiratory infections. We describe the rational use of probiotics in respiratory tract infections and detail the results of various clinical studies describing the use of probiotics in the management of respiratory infections such as nosocomial or community acquired pneumonia, or on specific grounds such as cystic fibrosis. The results are sometimes contradictory, but the therapeutic potential of probiotics seems promising. Implementing research to understand their mechanisms of action is critical to conduct therapeutic tests based on a specific rational for the strains to be used, the dose, as well as the chosen mode and rhythm of administration.

Controversies in the management of the critically ill: the role of probiotics

Probiotics are commercially available, viable, non-pathogenic micro-organisms that, when ingested in sufficient quantities, exert a health benefit to the host derived through modification of the gut flora, local release of antimicrobial factors, maintenance of integrity of the gut barrier, competition for epithelial adherence, prevention of bacterial translocation, and modulation of the local immune response. In critically ill patients, probiotics appear to lead to decreased susceptibility to antibiotic-associated diarrhoea, Clostridium difficile infections, ventilator-associated pneumonia, necrotising enterocolitis, acute severe pancreatitis, sepsis and multiple organ dysfunction syndrome as well as a shortened duration of infections. Current scientific evidence supporting the use of probiotics is not conclusive and is mainly derived from single-centre, not very well designed trials that are limited by many factors including small sample sizes, heterogeneity in the probiotic strains used, effectiveness of the combined strains, optimum dose regimens, frequency and duration of administration, and certainly incomplete knowledge of the mechanism of action of each strain. Probiotics appear to be well tolerated, whilst adverse events are very rare. The most commonly reported adverse events include bacteraemia, fungaemia and sepsis. At present, based on the available evidence and although helpful and relatively safe for certain disease conditions, routine use of probiotics in the critically ill is not recommended.

Reanimación y prevención de las infecciones nosocomiales

Los servicios de reanimación deben organizar de forma minuciosa la prevención de infecciones en sus enfermos, ya que éstos suelen estar inmunodeprimidos, están sometidos a múltiples procedimientos invasivos realizados por un personal sanitario variado, a menudo en situaciones de urgencia y a cualquier hora del día o de la noche. Las principales infecciones que hay que tratar de prevenir son las neumonías bacterianas adquiridas asociadas a ventilación mecánica (NAVM), las infecciones relacionadas con catéteres intravasculares y las infecciones urinarias asociadas al sondeo vesical. La incidencia de estas infecciones ha disminuido en la mayoría de los servicios que realizan un control cifrado, sobre todo gracias a la implantación de programas de mejora de la calidad. Las técnicas de prevención son múltiples y deben aplicarse simultáneamente. Incluyen medidas globales, como las modalidades de prevención de la transmisión cruzada (higiene de las manos, sobre todo) o de uso de antibióticos, concebidas para reducir la presión de selección de bacterias resistentes a éstos, así como medidas específicas relativas a la colocación y uso de cada uno de los dispositivos invasivos. Numerosas técnicas han demostrado su eficacia en estudios de buen nivel metodológico (higiene de las manos, apósitos para catéteres, etc.), mientras que otras siguen siendo objeto de controversias, por lo que las recomendaciones nacionales e internacionales se actualizan regularmente de acuerdo con los nuevos datos científicos. Estas medidas, implantadas de manera razonada en el marco de programas de mejora de la calidad, permiten obtener tasas muy bajas de infecciones relacionadas con el uso de catéteres vasculares y resultados menos satisfactorios con las NAVM, que justifican la necesidad de proseguir la investigación en este campo.

Rianimazione e prevenzione delle infezioni nosocomiali

I servizi di rianimazione devono organizzare la prevenzione delle infezioni nei loro pazienti in modo minuzioso, in quanto i pazienti sono spesso immunodepressi e subiscono gesti invasivi molteplici, realizzati da personale differente, spesso in situazioni di urgenza e a qualsiasi ora del giorno o della notte. Le principali infezioni che bisogna tentare di prevenire sono le polmoniti batteriche acquisite sotto ventilazione meccanica (PAVM), le infezioni su cateteri intravascolari e le infezioni urinarie su catetere vescicale. L’incidenza di queste infezioni è diminuita nella maggior parte dei servizi che ne effettuano un monitoraggio su base numerica, in particolare nel quadro di programmi di miglioramento della qualità. Le tecniche di prevenzione sono molteplici e devono essere applicate simultaneamente. Esse riguardano delle misure globali, come le modalità di prevenzione della trasmissione crociata (igiene delle mani, in particolare) o di utilizzo degli antibiotici nella prospettiva di ridurre la pressione di selezione di batteri resistenti agli antibiotici, così come delle misure specifiche relative al posizionamento e all’utilizzo di ciascuno dei dispositivi invasivi. Numerose tecniche si sono dimostrate efficaci in studi di buon livello metodologico (igiene delle mani, medicazioni dei cateteri, ecc.) mentre altre sono ancora oggetto di controversie, portando a raccomandazioni nazionali e internazionali regolarmente aggiornate in funzione dei nuovi dati scientifici. Queste misure, implementate in modo ragionato nel quadro di programmi di miglioramento della qualità, consentono di ottenere dei tassi molto bassi per quanto riguarda le infezioni dei cateteri vascolari e dei risultati meno buoni per le PAVM, illustrando la necessità di proseguire la ricerca in questo settore.

Probiotics in the critically ill: a systematic review of the randomized trial evidence

OBJECTIVE

Critical illness results in changes to the microbiology of the gastrointestinal tract, leading to a loss of commensal flora and an overgrowth of potentially pathogenic bacteria. Administering certain strains of live bacteria (probiotics) to critically ill patients may restore balance to the microbiota and have positive effects on immune function and gastrointestinal structure and function. The purpose of this systematic review was to evaluate the effect of probiotics in critically ill patients on clinical outcomes.

DESIGN

Systematic review.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We searched computerized databases, reference lists of pertinent articles, and personal files from 1980 to 2011. We included randomized controlled trials enrolling critically ill adults, which evaluated probiotics compared to a placebo and reported clinically important outcomes (infections, mortality, and length of stay). A total of 23 randomized controlled trials met inclusion criteria. Probiotics were associated with reduced infectious complications as documented in 11 trials (risk ratio 0.82; 95% confidence interval 0.69-0.99; p = .03; test for heterogeneity p = .05; I 44%). When data from the seven trials reporting ventilator-associated pneumonia were pooled, ventilator-associated pneumonia rates were also significantly reduced with probiotics (risk ratio 0.75; 95% confidence interval 0.59-0.97; p = .03; test for heterogeneity p = .16; I 35%). Probiotics were associated with a trend toward reduced intensive care unit mortality (risk ratio 0.80; 95% confidence interval 0.59-1.09; p = .16; test for heterogeneity p = .89; I 0%) but did not influence hospital mortality. Probiotics had no effect on intensive care unit or hospital length of stay. Compared to trials of higher methodological quality, greater treatment effects were observed in trials of a lower methodological quality.

CONCLUSIONS

Probiotics appear to reduce infectious complications including ventilator-associated pneumonia and may influence intensive care unit mortality. However, clinical and statistical heterogeneity and imprecise estimates preclude strong clinical recommendations. Further research on probiotics in the critically ill is warranted.

Small studies may overestimate the effect sizes in critical care meta-analyses: a meta-epidemiological study

INTRODUCTION

Small-study effects refer to the fact that trials with limited sample sizes are more likely to report larger beneficial effects than large trials. However, this has never been investigated in critical care medicine. Thus, the present study aimed to examine the presence and extent of small-study effects in critical care medicine.

METHODS

Critical care meta-analyses involving randomized controlled trials and reported mortality as an outcome measure were considered eligible for the study. Component trials were classified as large (≥100 patients per arm) and small (<100 patients per arm) according to their sample sizes. Ratio of odds ratio (ROR) was calculated for each meta-analysis and then RORs were combined using a meta-analytic approach. ROR<1 indicated larger beneficial effect in small trials. Small and large trials were compared in methodological qualities including sequence generating, blinding, allocation concealment, intention to treat and sample size calculation.

RESULTS

A total of 27 critical care meta-analyses involving 317 trials were included. Of them, five meta-analyses showed statistically significant RORs <1, and other meta-analyses did not reach a statistical significance. Overall, the pooled ROR was 0.60 (95% CI: 0.53 to 0.68); the heterogeneity was moderate with an I2 of 50.3% (chi-squared = 52.30; P = 0.002). Large trials showed significantly better reporting quality than small trials in terms of sequence generating, allocation concealment, blinding, intention to treat, sample size calculation and incomplete follow-up data.

CONCLUSIONS

Small trials are more likely to report larger beneficial effects than large trials in critical care medicine, which could be partly explained by the lower methodological quality in small trials. Caution should be practiced in the interpretation of meta-analyses involving small trials.

Sources, isolation, characterisation and evaluation of probiotics

According to the FAO and the WHO, probiotics are 'live microorganisms which, when administered in adequate amounts, confer a health benefit on the host'. The strains most frequently used as probiotics include lactic acid bacteria and bifidobacteria, which are isolated from traditional fermented products and the gut, faeces and breast milk of human subjects. The identification of microorganisms is the first step in the selection of potential probiotics. The present techniques, including genetic fingerprinting, gene sequencing, oligonucleotide probes and specific primer selection, discriminate closely related bacteria with varying degrees of success. Additional molecular methods, such as denaturing gradient gel electrophoresis/temperature gradient gel electrophoresis and fluorescence in situ hybridisation, are employed to identify and characterise probiotics. The ability to examine fully sequenced genomes has accelerated the application of genetic approaches to the elucidation of the functional roles of probiotics. One of the best-demonstrated clinical benefits of probiotics is the prevention and treatment of acute and antibiotic-associated diarrhoea;however, there is mounting evidence for a potential role for probiotics in the treatment of allergies and intestinal, liver and metabolic diseases. There are various mechanisms by which probiotics exert their beneficial effects: regulation of intestinal permeability, normalisation of host intestinal microbiota, improvement of gut immune barrier function, and adjustment between pro- and anti-inflammatory cytokines. The number of studies carried out to test the effects of probiotics in vitro and in animals is enormous. However, the most reliable method of assessing the therapeutic benefits of any probiotic strain is the use of randomised, placebo-controlled trials, which are reviewed in this article [corrected].

Ventilator-associated pneumonia and its prevention

PURPOSE OF REVIEW

Given that ventilator-associated pneumonia (VAP) causes substantial morbidity, mortality and costs, prevention of this infectious process is a major challenge.

RECENT FINDINGS

This study provides an update on the prevention of VAP, focusing on the ability of preventive measures to improve patient outcomes and concentrating wherever possible on the data published within the past 5 years. Particular attention is being paid to the latest approach to facilitate the implementation of those prevention measures known as 'care bundles'.

SUMMARY

Several preventive measures have been shown to reduce the rate of VAP but many less have demonstrated an impact on patient outcomes (noninvasive positive pressure ventilation, sedation and weaning protocols, selective digestive and oral decontamination and endotracheal tube with drainage of subglottic secretions). Patients at risk must be approached with a bundle of preventive measures. Beyond the theoretical frame, a great deal of attention must be given to the factors that might improve adherence to those preventive measures. Future clinical trials testing new strategies in preventing VAP should have patient outcomes (i.e. a reduction in the length under mechanical ventilation, in the duration of stay in healthcare settings or in antibiotic consumption) as primary end-points rather than VAP rates.

Synbiotic therapy reduces the pathological gram-negative rods caused by an increased acetic acid concentration in the gut

BACKGROUND

The mechanisms for the improvement of the gut flora and the intestinal environment by synbiotic therapy are unclear.

AIMS

This study evaluated the changes in the gut flora and the intestinal environment after synbiotic therapy, and tried to clarify the mechanisms by which synbiotic therapy reduces pathological bacteria in the gut.

METHODS

A total of 47 enteral feeding patients with long-term mechanical ventilation support were enrolled in the study. Patients were randomly assigned to synbiotic and control groups, at a two to one ratio. Patients in the synbiotic group were administrated Lactobacillus, Bifidobacterium, and galactooligosaccharides as synbiotics for 8 weeks.

RESULTS

The characteristics of the patients were not significantly different between the control (n = 16) and synbiotic (n = 31) groups. In the synbiotic group, the counts of Bifidobacterium and Lactobacillus in the gut increased significantly to 100 times the initial level following synbiotic treatment. The acetic acid concentration increased (71.1 ± 15.9 vs. 46.8 ± 24.1 μmol/g) and pH decreased in the gut in comparison with the control group. The concentration of acetic acid in the gut increased in proportion to the Bifidobacterium counts. The counts of pathological gram-negative rod decreased significantly to one-tenth of the initial level in inverse proportion to the Bifidobacterium counts. Furthermore, the amount of Pseudomonas aeruginosa in the lower respiratory tract decreased significantly after synbiotic therapy compared to the controls.

CONCLUSION

Synbiotic therapy reduces the pathological Gram-negative rods by increasing the acetic acid concentration in association with an increased counts of Bifidobacterium.

Fighting fire with fire: is it time to use probiotics to manage pathogenic bacterial diseases?

Probiotics, when considered in clinical practice, have traditionally been used for prophylaxis; however, there is growing data suggesting treatment benefits in numerous disease states. In this review, we focus on probiotics as treatment for and prevention of several acute and chronic infectious processes including Helicobacter pylori, Clostridium difficile, necrotizing enterocolitis, ventilator-associated pneumonia, vancomycin-resistant enterococci, and nonalcoholic fatty liver disease. It is inaccurate to generalize findings observed in a single probiotic species to all probiotics. This reasoning is due to the variability of colonizing abilities of native intestinal floras, probiotic or otherwise, secondary to different combinations, doses, and duration of treatments. Given these limitations, multiple animal and human studies have shown anti-inflammatory and selective antimicrobial effects of specific probiotics. Some studies suggest a role for probiotics as supplemental treatment, in combination with antibiotics, for the aforementioned disease processes. It is apparent from this review that the efficacy of probiotics is widely variable and multifaceted. More focused clinical and basic science research is necessary to better understand the treatment potential of various probiotics.

Probiotics in the intensive care unit

Probiotics are living microorganisms that, when ingested in adequate amounts, provide benefits to the host. The benefits include either a shortened duration of infections or decreased susceptibility to pathogens. Proposed mechanisms of beneficial effects include improving gastrointestinal barrier function, modification of the gut flora by inducing host cell antimicrobial peptides and/or local release of probiotic antimicrobial factors, competition for epithelial adherence, and immunomodulation. With increasing intensive care unit (ICU) antibacterial resistance rates and fewer new antibiotics in the research pipeline, focus has been shifted to non-antibiotic approaches for the prevention and treatment of nosocomial infections. Probiotics offer promise to ICU patients for the prevention of antibiotic-associated diarrhea, Clostridium difficile infections, multiple organ dysfunction syndrome, and ventilator-associated pneumonia. Our current understanding of probiotics is confounded by inconsistency in probiotic strains studied, optimal dosages, study durations, and suboptimal sample sizes. Although probiotics are generally safe in the critically ill, adverse event monitoring must be rigorous in these vulnerable patients. Delineation of clinical differences of various effective probiotic strains, their mechanisms of action, and optimal dosing regimens will better establish the role of probiotics in various disorders. However, probiotic research will likely be hindered in the future given a recent ruling by the U.S. Food and Drug Administration.

Probiotic, prebiotic, and synbiotic use in critically ill patients

PURPOSE OF REVIEW

To summarize the existing data regarding the use of probiotics, prebiotics, and synbiotics in select disorders encountered in the intensive care unit setting.

RECENT FINDINGS

Recent systematic reviews and meta-analyses have more rigorously aggregated the fragmented primary data which suffers from multiple limitations.

SUMMARY

Probiotics are living microorganisms which, when ingested in adequate amounts, provide health benefits to the host. The mechanisms of these benefits include improved gastrointestinal barrier function, modification of the gut flora by inducing host cell antimicrobial peptides, releasing probiotic antimicrobial factors, competing for epithelial adherence, and immunomodulation to the advantage of the host. In the intensive care unit, probiotics appear to provide benefits in antibiotic-associated diarrhea, ventilator-associated pneumonia, and necrotizing enterocolitis. With increasing rates of antibiotic resistance among common nosocomial pathogens and fewer new antibiotics in the research pipeline, increasing attention has been placed on nonantibiotic approaches to the prevention and treatment of nosocomial infections. Existing studies of probiotics in critically ill patients are limited by heterogeneity in probiotic strains, dosages, duration of administration, and small sample sizes. Although probiotics are generally well tolerated and adverse events are very rare, the results of the PROPATRIA (Probiotics Prophylaxis in Patients with Predicted Severe Acute Pancreatitis) trial highlight the need for meticulous attention to safety monitoring. Better identification of the ideal characteristics of effective probiotics coupled with improved understanding of mechanisms of action will help to delineate the true beneficial effects of probiotics in various disorders.

Probiotics' effects on the incidence of nosocomial pneumonia in critically ill patients: a systematic review and meta-analysis

Introduction

To evaluate the efficacy of probiotics in preventing nosocomial pneumonia in critically ill patients.

Methods

We searched PubMed, EMBASE, and the Web of Science for relevant studies. Two reviewers extracted data and reviewed the quality of the studies independently. The primary outcome was the incidence of nosocomial pneumonia. Study-level data were pooled using a random-effects model when I² was > 50% or a fixed-effects model when I² was < 50%.

Results

Twelve randomized controlled studies with a total of 1,546 patients were considered. Pooled analysis showed a statistically significant reduction in nosocomial pneumonia rates due to probiotics (odd ratio [OR]= 0.75, 95% CI 0.57 to 0.97, P = 0.03, I² = 46%). However, no statistically significant difference was found between groups regarding in-hospital mortality (OR = 0.93, 95% CI 0.50 to 1.74, P = 0.82, I² = 51%), intensive care unit mortality (OR = 0.84, 95% CI 0.55 to 1.29, P = 0.43, I² = 0%), duration of stay in the hospital (mean difference [MD] in days = -0.13, 95% CI -0.93 to 0.67, P = 0.75, I² = 46%), or duration of stay in the intensive care units (MD = -0.72, 95% CI -1.73 to 0.29, P = 0.16, I² = 68%).

Conclusions

The use of probiotics was associated with a statistically significant reduction in the incidence of nosocomial pneumonia in critically ill patients. However, large, well-designed, randomized, multi-center trials are needed to confirm any effects of probiotics clinical endpoints such as mortality and length of ICU and hospital stay.